hi guys , finally finished up my cab sim project.
i present ''ASTROSIM''
very happy with it, now i can just plug in a few pedals
and record/play without an amp, and silently too... 8)
special thanks to samhay for his input, and putting up with me annoying him a lot ha ha...cheers man. ;)
anyway...
includes line out, headphones out, and XLR out.....
Modern/Vintage switch.
and 3 tone/boost options.
at the end of the vid i added
a demo recording of double tracked guitar, with no post EQ at all...so you get an 'honest' idea of it..
with bass and drums...endure or enjoy... 8)
(https://i.postimg.cc/wTtwWRmn/astroschemo.png)
cheers rob. ... 8) 8) 8)
So, when you say, "USE NE5532 ONLY," what do you really mean by that? :icon_confused: :icon_wink:
It means don't mess with the spaceman: he's got you on long-range scanners. :icon_twisted:
Quote from: EBK on February 01, 2019, 02:24:24 PM
So, when you say, "USE NE5532 ONLY," what do you really mean by that? :icon_confused: :icon_wink:
The NE5532 works best because its driving abilities.bit is perfect for the DI and headphone out (although in my experience, a bit quiet at 9v)
It also is very low noise compared to a jfet opamp.
I assume you can use a tl072 for the filtering stage (very clever, astro!) But I don't know if the low input impedance of the ne5532 (300k) is used for something.
I want it!
holy shit mate, that sounds @#$%ing incredible!
pulled the trigger on a pcb, SOLD!!!!!
that said,, all the devices in the video sound incredible, along with your tone and playing.
right on rob!
thanks man!
Cheers guys, yeah the ne5532 behaves a lot better than the 072 for phones etc...
Hi Jimi, cheers man, all wrapped up, will send it off to you in the morning, if I don't get snowed in ha ha..
Thanks man . 8) 8) 8)
i may just replace my stage amp with it and go direct into the pa, man, that sounds killer bro.
well done!
where's a sausage when ya need one?
;)
Quote from: pinkjimiphoton on February 01, 2019, 07:06:23 PM
where's a sausage when ya need one?
(http://loop48.com/bump/wp-content/uploads/2012/06/sausage-on-a-fork.jpg)
Quote from: pinkjimiphoton on February 01, 2019, 06:10:22 PM
pulled the trigger on a pcb, SOLD!!!!!
I am also feeling the tug of the tractor beam... :icon_eek:
Sounds fantastic man, much kudos! Looks killer too!
i've been dicking around with an "everything in a box" for a while... a chinese chipamp, with delay, belton, a couple channels.. this thing would be perfect right between the channels and the amp. all in one 1590dd... 90 watts, runs off a computer supply.
but even better, is with this, screw the amp, i can just go di. i love it! was building a sansamp for that, but, hey, robs just plain sounds better!!
of course his pedals may have something to do with it too... that skinwalker is TITE!
' that skinwalker is TITE!'
yeah man, its very quiet too....nice for chunky stop start stuff.. 8)
i love a fet dirt.... :icon_twisted:
pcb on its way man... 8)
Good work, Rob....GREAT tone there! I'm impressed!
next time i order, gonna get the skinwalker and black triangle od, and probably the chasm too... i sold the one i built, the guy LOVES it and uses it as his main verb in his studio.
the three boards for 25 pounds is a great deal, just a little too broke to boogie right now.
but yeah.. i don't usually care for high gain stuff, but man, like i said, that sounds TITE!!!!! well done bro!
the astrosim really is the icing... and it tastes good!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
:)
Sound great! Super playing too!
Yeah sounds great.
Quote.nice for chunky stop start stuff..
Is that why you let more lows through?
Is "unnamed" 3 position switch all off in the centre?
(You could use a TL072 for the *sim part* but I you might need to add about 470 to 680 ohms between the output of the opamp and the feedback network (R12 and C10); C12 and HIGH pot still connect to the opamp output.)
I couldn't resist and simulated the cabsim section.
It's a delicate balance between the twin tees but i have some observations..
The gain at the high peak is 24dB...looks like it's too much. Are you intending to clip the highs? The following "passive" twin tee will reduce the harshness..
The middle active twin tee doesn't do much..looks like a mid boost, but with the values shown it gets buried by the treble boost..with some tweaks i got it to boost 2khz and make it resemble a celestion v30. But you have to change everything because it alters the balance..
Really nice simple concept!
QuoteThe gain at the high peak is 24dB...looks like it's too much. Are you intending to clip the highs? The following "passive" twin tee will reduce the harshness..
Without the peak, the high-end is a bit like the BlackStar HT5. The low-end also has some similarity with the BlackStar HT5. The ASTROSIM has more lows. The circuits themselves are quite different.
That "dual sallen key" filter on the HT5....never seen that before...
So many ways to peel a cat!!!
QuoteThat "dual sallen key" filter on the HT5....never seen that before...
So many ways to peel a cat!!!
It pops up now and then. IIRC it's in the Eden bass amps.
Works best when the HPF and LPF cut-off frequencies are far apart.
I think I'm going to try building this sometime in the nearish future (inserting it high into my queue). I found in my stash one NE5532 and two NE5534 chips (single op amp package, but with supposedly better noise performance -- I haven't looked at the datasheets). Any suggestions as to which parts of the circuit I should use the NE5534s, assuming I would ever be brave enough to disregard Rob's explicit admonishment, "NE5532 ONLY"? :icon_wink:
Cooked to perfection.
I dunno if C1 is drawn the wrong side of R2 in the scheme? Otherwise, the protection diode is half blocking C1 from helping.
Chips other than the NE5532 could work, but they can be more expensive and rarer, especially in the uk.
We've seen some more modern high-performance audio driver op-amps don't like resistor bias dividers. You could try LM833 or RC4580 etc if you want. I've seen the 4580 used in commercial products either for phones and balanced drive.
a 5534 is just a single OA version of the 5532. if ya like one, you'll like the other.
ca3140 ez is a cool chip i been playing with that may work well in single OA situations, it will work on stupid low voltages and can go half a volt below the rail without farting. cool chip, check it out!
QuoteQuote
The gain at the high peak is 24dB...looks like it's too much. Are you intending to clip the highs? The following "passive" twin tee will reduce the harshness..
Without the peak, the high-end is a bit like the BlackStar HT5. The low-end also has some similarity with the BlackStar HT5. The ASTROSIM has more lows. The circuits themselves are quite different.
I might need to retract that. I think something screwed up on one of my spreadsheets.
There is a response like the ASTROSIM without the HF peak but it might not be the BlackStar HT5.
Be warned - Apache Office has some nasty bugs when you copy sheets containing graphs.
If you select the graph then right click on a graph and see the option "Data Ranges" in the pop-up menu it's probably OK. If you see "Chart Data Table" it can easily screw-up (or is screwed-up). You cannot trust what you see, especially if you have edited something.
I guess you could use a RC4559 as well.
Err.. speaking of openoffice? Do you know if the bug you talk about is also in libreoffice?
Sounds fabulous Rob, as always. I'll have to throw it on the list 8)
QuoteErr.. speaking of openoffice? Do you know if the bug you talk about is also in libreoffice?
I haven't checked the Libre OpenOffice on my Ubuntu OS machine, which is also a later version.
I used Apache because I had problems with the Optimizer plug in and also Thai languages on other versions in the past. On both Libre and Apache, if you use plug-ins and other languages different things break on each version, sometimes crashing OpenOffice.
I noticed I get the "Chart Data Table" when I import from MS Office as well. Once you get the "Chart Data Table" case you are guaranteed something bad will happen down the track. It gets in a funny state and you can never get it back to the "Data Ranges" normal case.
I did do some searches and there were some issues in this area. Sometimes it was reported in a slightly obscure way.
I'll power-up my Ubuntu machine tonight and let you know.
Maybe I just don't know enough about cab simulators, but I'm confused about a couple things here:
Is the output jack connected to the Line Out on the schematic? What exactly does the stomp switch do in this circuit?
Quote from: EBK on February 06, 2019, 03:23:32 PM
Maybe I just don't know enough about cab simulators, but I'm confused about a couple things here:
Is the output jack connected to the Line Out on the schematic? What exactly does the stomp switch do in this circuit?
I'm building it without the switch, with the line out hardwired to the output jack. I think deadastronaut built this one with line out being an "effect out" and the switch bypassing the cab simulator to the output jack, but still keeping the signal going thru the cab simulator for the headphones and xlr outputs.
Quote from: Marcos - Munky on February 06, 2019, 05:11:58 PM
I think deadastronaut built this one with line out being an "effect out" and the switch bypassing the cab simulator to the output jack, but still keeping the signal going thru the cab simulator for the headphones and xlr outputs.
That's how I interpreted it as well. Headphones and XLR out are always on, line out is footswitchable.
^ yup..
basically a home recording box...does me. 8)
So, I built it (board and offboard wirings only, not boxed yet) and did a quick test. I'm getting sound out of the line out. Didn't tested the XLR out with a real cable, but I'm getting sound out of it with an audio probe.
My issue is on the headphone out. I'm not getting any sound out of it. I've checked the parts values, and everything seems to be ok. Using an audio probe I've tracked the signal to pin 5 of the 5532, but I'm not getting any sound on pins 6 (don't know if it's supposed to be audio signal there) and 7. Here's my voltages:
pin 5: 5.132 V
pin 6: 5.884 V
pin 7: 8.25 V
pin 8: 8.93 V
That pin 7 voltage looks suspicious, should it really be that high?
Any clues?
I'm thinking of building a cab sim. I like the XLR out and the extra controls on this pedal but from what I've heard i think the condor still sounds better so I'm leaning in that direction. What do you guys reckon? Condor vs Astrosim?
Quote from: Killthepopular on February 16, 2019, 01:32:34 PM
What do you guys reckon? Condor vs Astrosim?
Your ears are your ears. If the Condor sounds better to you, then build the Condor. If the Astro sounds better to you, build the Astro. Pretty simple decision, just trust your ears 8)
Quote from: vigilante397 on February 16, 2019, 07:30:40 PM
Quote from: Killthepopular on February 16, 2019, 01:32:34 PM
What do you guys reckon? Condor vs Astrosim?
Your ears are your ears. If the Condor sounds better to you, then build the Condor. If the Astro sounds better to you, build the Astro. Pretty simple decision, just trust your ears 8)
But, of course, you'll have to build both to know which one sounds better to you, so--Catch 22. :icon_mrgreen:
And when you've built both, there will be another. Feed the addiction ;)
I haven't build the condor or the astrosim..but i can bet that the astrosim will be much better. The condor is just one cabinet emulated. The astrosim has a similar approach as my multicabsim. You can tweak it to sound just like you want
Is this xlr out interface compatible with phantom power supply ? (i.e. it's not going to be damaged in case PS is activated mixer side)
It's not set up to use phantom power. And those output caps should mean there's no incoming DC to upset the opamps. I bet Paul knows the right answer!
Any suggestions on where one would implant a belton reverb module into this circuit? Not sure if it's something that should come pre-cab sim or perhaps it could be injected somewhere for best performance.
I've got parts on the way to tinker a bit. I wanted to see about including reverb without making a big deal about it. Just one extra knob - using the schematic they host on their website.
@bluebunny
maybe those caps end up reversed biased by a PS voltage? may be I'm wrong.
You could use NP electros? I've seen them used in a few balanced drivers.
That would be a good solution.
Quote from: Kevin Mitchell on February 19, 2019, 10:23:50 AM
Any suggestions on where one would implant a belton reverb module into this circuit? Not sure if it's something that should come pre-cab sim or perhaps it could be injected somewhere for best performance.
I've got parts on the way to tinker a bit. I wanted to see about including reverb without making a big deal about it. Just one extra knob - using the schematic they host on their website.
Would be a nice thing to add.. You could make it switchable easy enough pre/post. A tight slap reverb can do wonders. A compressor can also be a nice addition.
Phantom injection: look at the polarity of the output caps.
Quote from: Kevin Mitchell on February 19, 2019, 10:23:50 AM
Any suggestions on where one would implant a belton reverb module into this circuit? Not sure if it's something that should come pre-cab sim or perhaps it could be injected somewhere for best performance.
I've got parts on the way to tinker a bit. I wanted to see about including reverb without making a big deal about it. Just one extra knob - using the schematic they host on their website.
I would suggest you put a reverb beforehand.
Alternatively, splice it in at the point where C22, C16 and C15 meet.
Quote from: PRR on February 19, 2019, 07:17:13 PM
Phantom injection: look at the polarity of the output caps.
Indeed. Phantom power wasn't in the design brief.
However, it wouldn't hurt to make C20 and C21 NP with a max voltage > 48V as this is the only mod needed to make this tolerant of phantom power into the XLR outputs.
If you want the option to power it via phantom power into the XLR outputs then that would be a bit more work and would probably preclude the headphone output.
What would phantom power do to the XLR signal? I've been trying to look into it and get as far as powering condenser microphones.
My audio interface has the option but never thought much of it with the setup I have. Perhaps I had tried and it didn't do much for me. I remember I ran it with a dynamic mic and also line level guitar signal. Nothing beneficial happened really.
Phantom power on the XLR out will apply ~48V to the output side of the output caps (C20 and C21). If these are polarised capacitors as most 10u are, this will be a reverse volatage which typically leads to quite spectacular failure of the capactor.
Three options.
1. Don't apply phantom voltage to the XLR output.
2. Use non-polarised capacitors that have a voltage rating significantly greater than your phantom voltage (63V is probably ok, but 100V would be my choice).
3. Socket the capacitors and call it a feature. Fireworks mode.
Sorry my lack of understanding the use of phantom power had clouded my thoughts.
So phantom power is being brought up in terms of circuit protection of the cab sim from the 48volts. It doesn't do anything for the signal - is only used for condenser mics and would damage the circuit without precaution.
I think I've got it now. Glad I didn't blow anything up when I had the "what does this button do" moment :-[
Thanks
Exactly. This unit does not use Phantom. However your low-pay helper WILL "touch that button" and send Phantom TO it, just before a critical moment. BI-polar 63+V caps are wise on nearly anything with XLR outs.
Any particular reason to not have a volume control for the headphones? Someone is going to have headphones on before powering up, not realizing some volume is way too high and have a bad time. It's usually good practice to turn a piece of equipment on and turn the volume all the way down before putting headphones on.
Quote from: samhay on February 20, 2019, 09:58:38 AM
call it a feature. Fireworks mode.
;D
yeah i had no need for phantom power....
the original schemo did have a headphones vol control,
but i paired it back, and left it as a preset...
Quote from: PRR on February 20, 2019, 03:46:17 PM..
However your low-pay helper WILL "touch that button" and send Phantom TO it, just before a critical moment. BI-polar 63+V caps are wise on nearly anything with XLR outs.
...
Before digital consoles (mix-boards), "analog era" live sound guys were much more sloppy and not always sober of course. I had phantom sent to both my bass and my amp on several occasions (even on hi-profile events).
Zeners on output can help too.
couple of questions re mods?
incorporating a headphone level? replace r22 with a pot or r31? or something different?
also having an aux in and level? which could connect an external audio source into the headphone out? ie able to play along with a song etc?
I am toying with marrying the Astrosim to a modded mixer/output section from the JamMix (http://guitar-fx-layouts.42897.x6.nabble.com/JamMix-Headphones-Practice-Play-Along-Amp-td26681.html) for external audio source input and stereo headphone outs. And maybe stick Nathan's submini FB-2 clone (board on the way; tube here & waiting) in front as a preamp. I think this would be a lot more suitable (not to mention better sounding) than the old Behringer V-amp 2 I have been using for silent practice. (This would nicely address your wish, @njkmonty.)
My order finger is getting itchy...
Wow, this sounds really nice!
FYI I did some experiments with the headphone driver. It seems the optimum for the NE5532 is a single output resistor of 47 ohms (instead of your two resistors R25/R26). This will get you about 8mW into a 16 ohm load (i.e. 4mW per ear phone) with distortion below 0.05% until clipping. Don't use less than 47 ohms as this seems to provoke instability.
merlins mustache!!
so you mean replace both r25 and 26 with 47 r?
or replace both r25 and r26 with 47r and connect both left and right outputs together?
(https://i.postimg.cc/wTtwWRmn/astroschemo.png)
Quote from: njkmonty on April 04, 2019, 05:13:35 AM
or replace both r25 and r26 with 47r and connect both left and right outputs together?
Yes just one resistor, both outputs tied together.
Or I suppose you could just replace the two resistors with 100R each, with much the same result.
or use each halves of the ic ? or no real benefit
Quote from: njkmonty on April 04, 2019, 05:25:18 AM
or use each halves of the ic ? or no real benefit
Well, you'll get more power if you use one half of the IC for each ear...
so ill try both on breadboard , so just duplicate both when using both halves of chip
Quote from: merlinb on April 04, 2019, 05:03:37 AM
FYI I did some experiments with the headphone driver. It seems the optimum for the NE5532 is a single output resistor of 47 ohms (instead of your two resistors R25/R26). This will get you about 8mW into a 16 ohm load (i.e. 4mW per ear phone) with distortion below 0.05% until clipping. Don't use less than 47 ohms as this seems to provoke instability.
That's interesting. I guess that headphones are built with sufficient tolerances such that you will get a fairly balanced output. Do you get noticably better peformance than with 2 100R resitors?
I still didn't got the headphone out on my build working. I'll give a try on the 47r, maybe I get lucky ;D
after playing around with tda2822 chips and different other values and chips, i ended up with the following which i
stuck onto the end section of my cab sim.
surprisingly the simple Ne5532 sounded great by my ears so i gave up on the more component intensive alternative designs!
i tried up to 100k volume pot but found the 1kb gave me a better range and more control
(https://i.postimg.cc/3wNR4p2B/Screen-Hunter-17-Apr-06-09-52.gif)
Finally getting around to this, using Rob's board. Is this supposed to take board mounted 9mm pots, or offboard? Or, forget "supposed to"--did anyone build this and do it one way or t'other?
Also, I'm guessing the vintage/modern switch could be a SPST switching a 51k in parallel with the 100k, if that's what you have handy.
Hi Ben, no, it uses offboard 16mm....
Uses 3 way on on on
And a spdt 2 way...
Thanks, Rob, I guessed as much on the pots and ordered :). As for the switch, I think I was unclear: what I meant was that you can accomplish the same thing as the On-On (should you wish to) by wiring the 100k across the switch (i.e. always in-circuit) and just switch a 51k on/off with a SPST in parallel with it, since 100k || 51k = ~34k, and you have a 33k there as the Modern setting.
Quote from: Ben N on July 01, 2019, 07:35:48 AMyou can accomplish the same thing as the On-On (should you wish to) by wiring the 100k across the switch (i.e. always in-circuit) and just switch a 51k on/off with a SPST in parallel with it, since 100k || 51k = ~34k, and you have a 33k there as the Modern setting.
Sounds about right to me ;D
-KM
This is the best sounding all analog speaker simulation I have heard. It beats the "emulated" output on my Blackstar HT20 MkII, Peavey Classic 20MH and Sansamp. It's better than some convolution / IR based cab sims I have seen.
It must have taken you ages to tune. Do you have a sweep of the frequency response? There's a lot going on in the feedback loop of that op-amp :)
Hi everyone,
I built this astro sim with only a headphone output and I tacked an aux mixer onto the front end so that I could play along with my music. However, it does not work. When I plug in my headphones I can hear a hum (like when there's a cable with a free end plugged into an amp) and I can hear when I tap on the input jack, but I cannot hear any guitar signal from the headphone output. Audio probing shows the guitar signal to end at pin 2 of IC1. I also hear a *very* loud high pitched buzz when I probe Pin 2 of the Air potentiometer.
Here is the schematic I'm using:
(https://i.postimg.cc/5Xf3qJp3/Headphone-Amp-Schematic.png) (https://postimg.cc/5Xf3qJp3)
My voltages: (taken without a guitar, aux, or headphones plugged in)
IC 1
Pin 1 - 8.17
Pin 2 - 3.9
Pin 3 - 4.35
Pin 4 - 0
Pin 5 - 4.351
Pin 6 - 4.354
Pin 7 - 4.41
Pin 8 - 8.73
IC 2
Pin 1 - 8.25
Pin 2 - 0.20
Pin 3 - 0.33
Pin 4 - 0
Pin 5 - 4.283
Pin 6 - 4.34
Pin 7 - 4.29
Pin 8 - 8.73
Images of the board:
(https://i.postimg.cc/v4SVgwKD/dp1d-EVEEQs68-Rxa-DLAOYMQ.jpg) (https://postimg.cc/v4SVgwKD)
(https://i.postimg.cc/mczF76xj/k-O76i0e-NQSqd-Uvwao-UCf-KA.jpg) (https://postimg.cc/mczF76xj)
(https://i.postimg.cc/5jwLPGXk/l-Rn-Uf-C3-PRKu-OTnqrig-Yj-Uw.jpg) (https://postimg.cc/5jwLPGXk)
Am I making some noob mistake in the mixer stage? I'm not 100% sure if simply tacking it on was a good move.
> Here is the schematic I'm using:
IC1A has _no_ feedback. It gives infinite gain and no DC centering.
Go back and look at mixer circuits, find the difference.
Spot on PRR, thank you! Man, I can't believe I made such a dumb mistake.
I fixed it by soldering a 100k resistor from pin 1 to pin 2 on the bottom of the board. Now the circuit works like a charm.
It sounds really good! I really like the vintage/modern switch.
Cool, yeah the vintage mod is nice for bluesy and tight metal stuff... 8)
I use mine all the time now... 8)
forgot to post these....here is a slimmed down version on the same pcb.
just no phones, or xlr.
(https://i.postimg.cc/sxRG2VV9/20200302-083240.jpg)
(https://i.postimg.cc/tRhVMV5r/20200302-083850.jpg)
(https://i.postimg.cc/brHDDKrX/20200302-083928.jpg)
Love the artwork, slick work as always Rob 8)
cheers man, my mate wanted a small desktop version just so he can plug direct into his mixer
as he has no amp the poor bugger lol. :icon_mrgreen:....but he has pedals. ;)... 8)
no etch, just toner transfer... ::)
Quote from: deadastronaut on February 01, 2019, 02:01:15 PM
hi guys , finally finished up my cab sim project.
i present ''ASTROSIM''
very happy with it, now i can just plug in a few pedals
and record/play without an amp, and silently too... 8)
special thanks to samhay for his input, and putting up with me annoying him a lot ha ha...cheers man. ;)
anyway...
includes line out, headphones out, and XLR out.....
Modern/Vintage switch.
and 3 tone/boost options.
at the end of the vid i added
a demo recording of double tracked guitar, with no post EQ at all...so you get an 'honest' idea of it..
with bass and drums...endure or enjoy... 8)
(https://i.postimg.cc/wTtwWRmn/astroschemo.png)
cheers rob. ... 8) 8) 8)
Hi Rob. can i plug the guitar directly to this cab sim and use the headphone out? Or do i need some type of power amp? I was planning on building a cabinet simulator and a headphone amp together in a simple 1590bb box but if this has the two sections inside im going with this one! It sounds spectacular!
Hi yes you can do that, no probs....
Leave off the xlr parts, and you can squeeze it into a 1590bb with a small phone socket.
I'm actually using it with no XLR as the cab sim and headphone out for some onboard guitar electronics. I've got a surface mount PCB designed that has a Zendrive into an EP-101 preamp into the Astrosim. Still need to breadboard it to make sure I like the sound (mostly concerned about the choice of the zendrive). It will be going in a travel guitar I have designed where there is a separate jack out for headphones and one for an amp. Should make it an all-in-one travel solution.
Alright, so I got my board all populated. I have good signal all the way to pins 5/6 of the NE5532. However, pin 7 is very crackly and something is clearly wrong. Audio probing on pins 5/6 sounds fine, voltages look to be about what is expected for the topology. Is it possible to damage one opamp in a dual opamp package? I don't have any spare 5532's at the moment, so my choice is to see if there is something else wrong or to swap it out. This is a SMD board, so I can't just pop the chip out of a socket, it's a little more hassle than that. Any thoughts on a replacement for this application?
Brief update: I swapped out the NE5532 for a TLC2262 (only other SMD dual opamp I had on hand) and I have the same problem where the pin 7 output is really quiet, buzzy, and nasty. Not too sure what is going on here, but I put the 5532 back as it doesn't seem to be the issue. I disconnected the resistors to the output, same result. I checked the capacitance from pin 7 to the 470R resistors at output and they read 100 uF, as expected. I also checked the components in the feedback loop and they seem fine. Here are my voltages:
Source: 8.5
pin 1: 3.8
2: 3.75
3: 3.75
4: 0
5: 2.34
6: 2.9
7: 1.27
8: 8.5
I am using the schematic from the initial post, excluding the XLR out but using the headphone out. Any thoughts on what might be the issue? That pin 7 voltage seems fishy, but I don't know what could be causing it. I have checked for solder bridges and loose joints and everything appears in order, but clearly something is wrong...
I think I found the issue. I wanted some form of headphone volume control, so I put a trimmer in place of the 6k8 on the pin 5 input. Turns out I wired it like a traditional volume pot and not a variable resistor, which messed with the bias, which would explain the nasty, fizzy, buzzy sound. I still need to try one more thing and make sure that it works end to end, but I think I solved the issue there. I'll report back.
OK, confirmed the miswired trimmer was the issue. Makes sense, since it was bleeding off lots of VREF bias to ground through the trimmer. It now works and sounds great! I have it wired with a zen drive and EP101 preamp onboard my little travel guitar, and it sounds great! I might be clipping when really digging in a little bit, which is probably a resistor selection issue with the EP101, since it is a fixed level. Still, I'm digging it!
cool glad you got it sorted man. easy mistake to make with vol trim...
i use mine all the time pretty much now... 8)
8)
Quote from: merlinb on April 04, 2019, 05:24:28 AM
Quote from: njkmonty on April 04, 2019, 05:13:35 AM
or replace both r25 and r26 with 47r and connect both left and right outputs together?
Yes just one resistor, both outputs tied together.
Or I suppose you could just replace the two resistors with 100R each, with much the same result.
Hey Merlin, hope you see this! If one were to use the 47R resistor, does that mean there is only a single output cap that is effectively 200 uF? I'm looking at ways of simplifying my layout and if I could ditch one of those caps and one output resistor, it would save me quite a bit of space.
Quote from: Ripthorn on May 28, 2020, 12:50:47 PM
OK, confirmed the miswired trimmer was the issue. Makes sense, since it was bleeding off lots of VREF bias to ground through the trimmer. It now works and sounds great! I have it wired with a zen drive and EP101 preamp onboard my little travel guitar, and it sounds great! I might be clipping when really digging in a little bit, which is probably a resistor selection issue with the EP101, since it is a fixed level. Still, I'm digging it!
So you wired you're volume pot with one leg to ground whilst the signal is floating around Vbias, have you ever considered to connect that volume pot leg to Vbias instead ;)
Quote from: niektb on May 29, 2020, 02:24:09 AM
Quote from: Ripthorn on May 28, 2020, 12:50:47 PM
OK, confirmed the miswired trimmer was the issue. Makes sense, since it was bleeding off lots of VREF bias to ground through the trimmer. It now works and sounds great! I have it wired with a zen drive and EP101 preamp onboard my little travel guitar, and it sounds great! I might be clipping when really digging in a little bit, which is probably a resistor selection issue with the EP101, since it is a fixed level. Still, I'm digging it!
So you wired you're volume pot with one leg to ground whilst the signal is floating around Vbias, have you ever considered to connect that volume pot leg to Vbias instead ;)
That's a great idea! I've never really done a lot with opamps, mostly discreet transistors and tubes, so the while biasing thing is something I'm still learning.
Hey all, hate to be a pedant here but the build docs state a dpdt On - Off - On but earlier in this thread Rob mentions it needs to be On - On - On. Will either work, or which is it?
Ive never had to use On - On - On and from a quick search they don't seem to be quite as widely available so hopefully the former.
Also, while I'm here R9 is 220R I take it rather than 220k?
Not meaning to nitpick, just trying to avoid running into problems
Cheers!
on off on will be fine man.........
yep 220r...
vintage modern is a 2 way toggle..
the other is 3 way....
Cheers man, good stuff!
Just a few parts to order then. And those xlr sockets I could swear I have somewhere to find.
Quote from: deadastronaut on March 12, 2020, 03:31:12 AM
Leave off the xlr parts, and you can squeeze it into a 1590bb with a small phone socket.
Ah crap. My 1590BB just arrived and I was planning on squeezing this thing in
with XLR. And headphones. And a 9v battery. And a belt clip. I was also toying with the idea of throwing in a Muff Fuzz or something similar :icon_lol:
I'm not sure what I was thinking! Time for a rethink. I'm tempted to just go back to sleep in the hope the enclosure looks bigger when I wake up again.
:icon_mrgreen:
Make the 1590b version....
Quote from: deadastronaut on March 11, 2020, 09:47:28 AM
forgot to post these....here is a slimmed down version on the same pcb.
just no phones, or xlr.
(https://i.postimg.cc/sxRG2VV9/20200302-083240.jpg)
(https://i.postimg.cc/tRhVMV5r/20200302-083850.jpg)
(https://i.postimg.cc/brHDDKrX/20200302-083928.jpg)
That's reassuring. I feel a bit better about it now and think I can squeeze it all in.
Now I just need to work up the courage to either venture into the loft in search of some old cat5 for donor wire or just grow some balls and attempt to wire up 2 pots, 4 switches, xlr and headphones using my big spool of black awg22. I'm a bit fearful of the prospect of having to troubleshooting a birds nest of wire that's all the same colour.
If nobody hears from me by Friday, uhm... Wait a little longer.
Cheers Rob this thing is excellent.
Currently using it as a headphone amp attached to my guitar strap with a switchable meathead and bass fuzz up front. Not the best choice of preamp but I just wanted to see how much I could cram into the one enclosure and see how usable it would be. I'll probably switch out the bass fuzz for something else further down the line but for now I'm having a lot of fun. Might be a late night.
I just ordered a board, been meaning to put this one together for a while now! Sounds very promising. I currently use an old Digitech pedal to interface with the PC for recording, may go line-in with my pedals as Sim sounds like it can do the job nicely!
iain...nice one..
mike, pcb is on its way to you... ;)
ive been using mine all the time on my bench into my mixer, haven't turned my amp on at all for the last few months...been recording a lot through it with guitar and bass...and electro acoustic
double tracking guitars is awesome...no noise or hiss, and very little post EQ too...
so am well happy...especially with the vintage/modern switch..very handy for metal or overdrives...
8)
Hey guys, I just finished building an Astrosim revision 2 board with the XLR and Headphone output. I'm having a little trouble with the tone on/off/on switch when using the headphone amp and the XLR out. The normal guitar level output works as expected when flipping the switch and sounds great, but the only way I get output on the headphone and XLR output is when the switch is in the off position. If it's not, I get a really awful screeching and buzzing sound with no output. I tried playing with various schemes of grounding the outputs to eachother or the case, but there's not a lot of change. When I plug the guitar line out into something with the headphone out connected it still buzzes on both, but once I disconnect the headphones the buzzing goes away on the guitar line out. Any thoughts on where I should start looking? It almost sounds like it's ground looping somewhere but I'm not too sure where to look. Thanks for any help :)
One thing I discovered as I tinkered with it some more, the problem clears up if I max out the high tone control pot, but once you raise the resistance up just a tad it comes back. It's the correct B5K Pot and seems to be in spec.
HI man, thats weird, as the tone control is only switching in and out a couple of caps and should have no effect on any of the outputs like that....hmmmm...
did you do the XLR 'bridge' mod as in the the bottom of the pdf?.
I've added and removed the bridge a couple of times, there's not really any change in the circuit at the moment thought I'm sure I'll want it in once I get past this problem. I noticed someone earlier in the thread mentioning that they were leaking VB through a pot, so I pulled out my multimeter to check and sure enough when the tone caps switch is in the off position, I can manipulate the pot's and the VB stays consistent, but when I put one in the circuit VB varies as I manipulate the pot. What's the correct wiring for the pot's? Maybe I'm just getting it wrong or something? I'm currently just wired Square pad to the 1st lug, middle to middle, and furthest left to the 3rd lug on all 3 of them.
pots should be , when looking at the back of the pot.. (not the shaft side)
3 2 1 (1 being the square pad. )
same as looking at the top of pcb...
3 2 1 (square pad)
'' but when I put one in the circuit '' ?
Yeah, that's how mine are wired, so I guess that's good then. I mean't one of the tone caps on the on/off/on switch. When I use the switch to put either cap in the circuit the VB starts changing. When it's plugged in through the normal guitar jack only the VB is consistent through all the switch positions, but I do get a little noise when the high pot is wide open, as soon as I plug in the phones the noise comes back on both the headphone out and the guitar line out. I haven't tried the XLR in a little while, but the behavior was the same as the headphone jack earlier.
strange, i use mine all the time i have it on my bench right now, i have just tested with line out, and headphones simultaneously at the same time and switched the tones,
no problem.......i cant see how just switching caps would cause screeching.......hmmmm....
my headphone socket is a plastic socket...not that it should matter...hmmmmm....just thinking aloud...
So is mine, I'm using an amphenol cliff style jack for all of the 1/4" I/O. It's especially strange because you would think if it was working on one output the remaining outputs would either not work at all or work normally at that point.
Have you got any pics.....just curious.
Many eyes on it might spot something.....
Sure, here's a photo. Nevermind the cap that I just melted a little with my soldering iron last night as I was remelting my off board connections to make sure they were solid, seems to be holding up but I'll likely swap it out when I can get another. Nothing really changed after that happened. Today I bypassed the XLR out by removing the XLR volume pot to try and limit the problem down and everything is working great except when I get to the very end of the high pot, it starts to trip out. I'm thinking I'll try a different pot of the same value, maybe this one is just crap? I have one on hand that's probably too big to fit in the pedal physically, but is the right value.
(https://i.postimg.cc/XGYDDZCQ/20200825-180511.jpg) (https://postimg.cc/XGYDDZCQ)
Did some more messing with it tonight. Tried another 5k pot in the high tone stack and nothing changed. I tried it with a quieter amp than my Marshall clone, and found that there is a bit of noise on the guitar output too when the high tone is wide open, but it's less pronounced than the headphone out. If I raise the resistance in the high pot above 6 or so ohms, the noise goes away, the pedal is dead quiet, and everything works great on both outputs. It's almost like flipping a switch and there's a big squeal if I go lower than that, and then at 0 ohms the squeal goes away but it's all hiss and and a super distorted version of the guitar tone. I'm almost thinking I should add a 10ohm resistor to the pot so that it never drops low enough to cause the squeal, but that seems like I'm just covering for something else wrong with my build somewhere. The XLR pot is still out of the circuit to keep it simpler till I get this part dialed in. Maybe theres a resistor somewhere that's too far out of spec?
Hi Drumm, you'll get it working...umm, pic of the other side of the board if you can? Wondering how you melted that cap when the serious stuff happens on the other side ;)
I built this and it was fine (Great project in fact! Lots of fun to use), but at first I had a build error. When probing, I got a squeal at one of the lugs of the "air" pot IIRC. The cure was to notice I'd left out a load resistor (R20 probably). These things are typically mistakes we make in assembly, just a matter of finding them!
Quote from: drumminkiger on August 26, 2020, 03:22:59 AM.......I raise the resistance in the high pot above 6 or so ohms, the noise goes away, the pedal is dead quiet, and everything works great on both outputs. It's almost like flipping a switch and there's a big squeal if I go lower than that, and then at 0 ohms the squeal goes away but it's all hiss and and a super distorted.......
It squeals. When C11 C13 are direct connected to IC1_A, it squeals radio waves. You don't hear that but it messes-up the opamp's audio performance, hiss and distortion.
The abrupt shift depends on pot quality, a pot with large end-resistance may not get it into trouble. Yes, 47-100 Ohms series to the pot seems wise.
But it seems it also squeals audio. That is often layout, long wires and sneak-back from output to input.
I'll grab a shot of the backside when pull it apart again. Lol, this is one of my first stomp boxes, but I've built lots of balanced audio circuits like mic pre's and compressors so if there's something wrong with it I know it's something I goobered up and need to hunt down :) This thing sounds awesome aside from this issue though, it is indeed a great project, and I enjoy it much more than plugging into an audio interface and a laptop to get a cabinet simulation.
If it's sneak back from output to input, could it be my foot switch wiring? Or perhaps my use of insulated cliff style jacks when maybe I should be using something like a switchcraft 11 jack so it's grounding to the chassis at the input and output by default? I've tried grounding them with alligator clips for testing and didn't find a lot of change, but I'd be happy to be wrong. I've also grounded the input and output jacks to the board, in the photo's Rob hasn't connected the input to ground it looks like on his initial post, but mine sounded like a ground lift when it wasn't grounded so I added it. Maybe my leads for the pot's are too long? I've tried to keep them at a practical length to accommodate getting them installed in the box with the board not mounted yet but not any longer than necessary. Thanks for you input guys, I really appreciate it.
Here's mine:
(http://www.bouron.org.uk/marc/sim040.jpg) (http://www.bouron.org.uk/marc/sim041.jpg) (http://www.bouron.org.uk/marc/sim042.jpg)
Added a ground lift switch and a second 3.5mm headphone socket.
Quote from: bluebunny on September 20, 2020, 08:59:53 AM
Here's mine:
(http://www.bouron.org.uk/marc/sim040.jpg)
It can be hard to make those knobs look good on a build, but they absolutely work there. Looks great 8)
Thanks Nathan, I thought the same. I've bought a bunch of smaller knobs for Eurorack builds, but the majority use 9mm pots and mine all have smooth 1/4" shafts - these tiny knobs tend to be T18 splined.
8)
looks great marc.... like the added hp socket , handy , and ground lift too....neato. 8).
Thanks mate - it's a neat little project. Keep 'em coming! :icon_cool:
I have found myself playing more with headphones recently and at the same time I have got a pretty powerful computer I can use for experimenting with recording. As I could need a cab sim for this, I searched for an AstroSim vero layout as this is my preferred medium. To my big surprise no one seems to have made one. A couple of weeks ago I had a cross country train ride (only 3 hours, Denmark is a very small country), and spent the time trying to make one.
It is my biggest vero layout to date, but it was pretty easy. I omitted the XLR out, mostly to keep the complexity down, but also because I do not have any equipment with XLR's. As an afterthought I also made a separate XLR out board.
The layout is not verified, but I have checked the nodes a few times, and it looks OK.
Here they are, freshly uploaded to the gallery. Let me know if you find something.
(https://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=53899&g2_serialNumber=2)
(https://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=53902&g2_serialNumber=2)
https://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=53899&g2_serialNumber=2
https://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=53902&g2_serialNumber=2
Quote from: cab42 on December 08, 2020, 05:26:15 PM
(https://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=53899&g2_serialNumber=2)
(https://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=53902&g2_serialNumber=2)
https://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=53899&g2_serialNumber=2
https://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=53902&g2_serialNumber=2
Hey what is R12 here?
Also what pot types are on the main board? Linear or log?
Quote from: VoivoD on November 02, 2021, 01:14:54 PM
Hey what is R12 here?
Also what pot types are on the main board? Linear or log?
The pots on the main board are both linear. The B is for linear. A is for audio or log. But check the schematic to be sure. The same goes for R12.
I'm pretty sure its 100 ohms but check the schematic to be sure. Just checked, its 100k.
BTW: The layout is not verified yet. I have a partly finished board on my table, that I hope to do something about in the near future.
If you start building, I will advice you to check the layout against the schematic first. I did check the nodes, but I might have missed something.
Well, assumptions are the mother of all screw ups. I just checked my own build, and I have put in a 100 ohm for R12, probably assuming that the null prefix meant that there was none.
Never trust a layout on the internet, appearently not even your own. :P
Thanks Voivo, you saved me for a lot of debugging time.
I breadboarded the circuit and wow...congratulation Deadastronaut on a brilliant design. It sounds excellent (even better than my amp+loadbox+Ir). I wish I had even a tenth of your knowledge and understanding of circuitry so I have a couple of questions that probably will demonstrate all my ignorance on the topic.
1) Can C4 C23 be substituted by a single 150n capacitor ? Same for C11 C13 (15n), if yes would it make much of a difference?
2) Is it possible to do mono in - stereo out (as in 2 mono out) ?
3) what about stereo in(2 mono in)- stereo out(2 mono out)
The reason for point 2 is that this way I could try and feed 2 different types of DI/preamp simultaneously before hitting the converters.
The reason for point 3 is for using a stereo reverb pedal before the Astrocab rather than after
I do apologies if these are silly questions so feel free to ignore them if they are
Once again ...great design
no such thing as silly questions here... ;)
hi, yes the caps substitutes will be fine...
to do stereo you may as well build 2 astro cab sims...(maybe in one unit)
then you have the best of all options your after.... 8)
cheers man, rob. 8) 8) 8)
Thank you Rob, much appreciated...and thank you also for the welcoming (that was my first post on the forum)
Last week I finally finished my vero build, and it actually works! However, I need to spend some more quality time with it before I will call it 100% verified.
I had some issues, but they were all related to sloppy soldering and a bad switch (and a trace cut in a wrong spot, but we don't talk about that).
One thing puzzles me. I have just above 9V on the V+ on the board, but my Vref as well as pin 1-3 and 5-7 on the IC is around 5.5V. I would have expected them to be around 4.5V. I have checked the resistors on the voltage divider, and they look fine. Is that a problem?
But it seems to work as expected. It sounds great through headphones, either on its own or together with a sub mini tube preamp. I haven't tried the line out yet.
During the debugging I checked the layout at least 10 times and I am pretty confident that it is correct.
I did one thing different in the build compared to the layout. Instead of making the double link under the IC, I ran the jumper directly from P8 to C8, moved R5 one column to the right, and placed a jumper from P2 to L2.
I will probably try to incorporate a volume control for the headphones and an aux input. There are some suggestions in the previous pages for that.
Now I need a big box! Maybe even with room for a tube preamp.
Oh by the way guys i had some 1590b small sized pcbs made
Of just the cab sim part...no phones/xlr , handy for an easy cab sim build..
Verified. 8)
https://deadastronaut.wixsite.com/effects/astrosimcabsimulator
Where is R14 and R15 on the schematic?
The unknown knows... :D
At the modern, vintage switch.. ;)
Quote from: VoivoD on December 24, 2021, 02:58:14 AM
Where is R14 and R15 on the schematic?
Run a wire from B1 on the vero to the middle lug of the V/M-switch. Solder R14 to one of the outer pins and R15 to the other and solder the other ends of the resistors together. Connect this junction to lug 1 on the air pot. Something like this:
(https://i.postimg.cc/F18fVf5J/vmswitch.png) (https://postimg.cc/F18fVf5J)
Hope that helps.
Abandoned since I will do everything digital. Sorry for not replying to pm, but it asks me too many questions and could get past them with correct answers.
Hi, I recently bought two of these PCBs via Musikding. Both PBCs are labeled as 2018 V2, although all the documentation I have seen is previous to this version. Also, both PCBs are missing all the tags/names for all the cabling (so no 9v, ground markings, etc). Should I take any special considerations or i can just go with the old documentation and assume all the connections are the same?
Thankss
Quote from: Marcseo on December 22, 2023, 02:55:53 AMHi, I recently bought two of these PCBs via Musikding. Both PBCs are labeled as 2018 V2, although all the documentation I have seen is previous to this version. Also, both PCBs are missing all the tags/names for all the cabling (so no 9v, ground markings, etc). Should I take any special considerations or i can just go with the old documentation and assume all the connections are the same?
Thankss
use the document pdf for labelling. and they will be fine.
rob.