Finally I've depotted my faulty NTMB onboard bass preamp. All parts were identified by their labelling and/or measuring with my DMM. Could some one please have a look whether the schemo makes sense. Interestingly Vref is NOT exactly V/2, whats the use of this?
I also did a simulation in LTSpice and all pots do what they are supposed to do. I will post images of the simulation later on.
Thanks for your help in advance.
Markus
(http://img.photobucket.com/albums/v21/markusw/NTMBschem.jpg)
Fantastic! How big of a circuit board did the thing take up?
Glad to hear that someone has a use for it!
Actually it uses two small PCBs. See also http://diystompboxes.com/sboxforum/viewtopic.php?t=30484&highlight= for a pic of the unit before depotting it.
One PCB measures 41x23mm, it carries the opamp, virtual gnd circuit, input, output and the bass control parts. Treble and mid control parts are on the second PCB that is 23x29mm.
Both PCBs were shielded by a brass foil, at least it looked like brass. The layout was rather dense with some jumper wires crossing several components, though not really tidy. But who cares, it was a nice sounding unit before it got faulty.
I am right now doing the layout for my clone. Since my Carvin has a large and nicely copper shielded cavity I do not stick to the Bartolini layout. Furthermore, I want to use PCB mounted pots, so I'm restricted anyway.
Good luck,
Markus
Great marcus :)) !!!
Thanks :) :D :D
Nice job. I had the same question about an asymmetric voltage divider in the power supply re: my Soundtank FZ5 Sixties Fuzz. Still curious about the answer. Edit: Ah, just saw the other thread--never mind.
BTW, does that Bartolini require special (lo-Z?) pups?
Ben
Ben, bartolini are like other pickups, az you see for volume there is used 250k pot. You can use bartolini pickups without this NTMB, and you can use ntmb with any other single pickup.
Nikolay,
Am I missing something? You may be right about the pickups, but the vol pot I see in the schematic is 25k and comes after active circuitry, so it does not interface with the pickups at all. Or do you mean that 250k is the recommended pot value for using the pickups passively?
Ben
Quote from: Ben NOr do you mean that 250k is the recommended pot value for using the pickups passively?
Ben
Yes ;)
What do those B2Grey, B2Viol, B2Orange and others refer to ? Are they wires from the Bartolini active pickup ? If yes, how to adapt the schematic with a pickup wich has only 2 wires ?
QuoteWhat do those B2Grey, B2Viol, B2Orange and others refer to ? Are they wires from the Bartolini active pickup ? If yes, how to adapt the schematic with a pickup wich has only 2 wires ?
They just connect the two PCBs/blocks of the NTMB. If you look at the NTMB wiring diagram, you can find them too. I just added it for internal reference.
Regarding the blend pot: its a double MN tapered pot (250k). I suppose it could also be used for just mixing two passive pickups without the subsequent NTMB. For the exact wiring of the blend pot please refer to the NTMB wiring diagram (can be downloaded from the Bartolini hp). Two active pickups probably might overload the NTMB (depending on the setting of the trimpot).
Regards,
Markus
I just updated the schematics. Now the blend pot is included too.
Good luck with your clones :wink:
Markus
Thanks man.
Hi. I almost finished building the clone. I just wanted to know where the grey wire should go (as it has a start, but no ending). As you said it connected the two PCB to each other, but a loose wire?
Second, is it possible in this NTMB to add a second 9V battery to get more headroom (don't know what model I just cloned).
Thanks!
QuoteI just wanted to know where the grey wire should go (as it has a start, but no ending). As you said it connected the two PCB to each other, but a loose wire?
Sorry, I did'nt describe it properly. There are three wires (grey, orange and violet) that connect the mid and treble control PCB with the main PCB (basically the caps and resistors as well as the coils for the mid and treble control are connected via these three wires to the second opamp on the main PCB) I just added the labels for internal reference. So all connections are shown in the schematics. Maybe it's better if I delete the labels.
It's the 9V version. However, if the caps (esp. the tants) you're using are rated a high enough volatage, I suppose you can connect two batteries to it. The opamps should'nt have any problems with 18V.
Good luck with your clone. BTW, where did you get the MN taper blend pot?
Markus
OK, thanks! Will go on. The guitar store on the corner here supplied them, but I had too much pots already going so I decided to get total control and added two individual volume pots (small ones, stock). Now I have 6 knobs on my jazz bass...... and a switch
QuoteNow I have 6 knobs on my jazz bass...... and a switch
:shock:
What controls do you have?? Two volumes, bass, mid, treb, ....:?:
Markus
6 knobs:
- volume neck
- volume bridge
- bass
- treble
- mid
- end volume
and a 3 way switch to add 3 bands of mid control
the end volume knob is a push / pull pot switching passive / active.
Quotethe end volume knob is a push / pull pot switching passive / active.
how do you switch the NTMB active/passive?
OK, it is not that great; it is a bypass switch so I let the signal from my pickups or through my clone NTMB or directly to the output (I have no treble / bass control than).
There is a wiring guide on the Bartollini website.
I did'nt want to drill a 6th hole for a mid select switch. Also I could'nt find a concentric dual pot for a continous mid sweep like some of the EMGs have. Therefore, I added a 6-fold micro switch to my layout to switch several mid caps. I my original NTMB there was a 100nF mid cap. By pulling the pot it was switched out of the circuit. However, I never used this setting since it took away to much bass IMHO.
I'm keen to see/hear your clone.
Markus
HA, me too.....
dual concentric pots were hard to find, and way to expensive. So I was forced to use individual pots.... I've now narrowed it down to 5 pots (found a blend pot very cheap).
(and I like to have total control)
One last question: are the values of the inductors that high? (150 milli Henry?). I have a lot of problems getting them here......
QuoteOne last question: are the values of the inductors that high? (150 milli Henry?). I have a lot of problems getting them here......
I did'nt measure them but they were labelled 154J, so they should be 150 mH. I also could'nt get 150mH coils. Therefore, I replace them with three 100 mH.
Markus
Ah OK, I did the same.
I could not get hold of the IC so I swapped it with a OPA2134 IC I had laying around (few samples). Now waiting for the last part and I am ready to turn it on (and off of course).
I was thinking too to check how it sounds with Burr Brown opamp. Unfortunately, they seem to draw much more current from the battery than the MC33178. Anyway, it will be interesting to hear if they sound different.
QuoteNow waiting for the last part and I am ready to turn it on (and off of course).
Right now, I'm etching the PCBs for my modded version. Basically, it has two input buffers that get blended by a fake log/antilog pot. Since I intend to put it into my Carvin bass that has a large, shielded cavity and I wanted to reduce the number of cables I'm using PCB mounted pots.
Markus
Nice... PCB..... No, I am using a breadboard; only things I have right here. The IC will come somewhere next week (free samples!!) and my new control plate will come soon I hope.
We'll see!
QuoteNice... PCB....
I like to use them because once the layout is done on the PC, things usually work. Especially since the only equipment I use for making foto PCBs is a writing desk lamp, some transparencies and a inkjet/laser printer....and a little trial and error :wink:
Markus
Have fun. Let me know how it works out!
Thanks for passing this along Marcus!!!!!!!!!!
Hello...
I was looking for the MC33178 ic ... and I found at TI that the TLE2142 is a direct replacement for that motorola ic.
But I know almost nothing about that TLE family. Could we use them as replacement for tls and stuff like tl072 ?
Thanks for your help
Gabriel
Gabriel,
The TLE2142 op amp has a bipolar input stage which is fairly quiet for a bipolar op amp 10nv/hz, and has a low 1/f corner of only 10 hz.
As long as your source impedances are low, you can use it lots of places and get good performance.
It's not a good sub for a TL072 in circuits with higher source impedances because even though the '072 has higher voltage noise, it has much lower current noise which makes it a nice low noise op amp at higher source impedances (>8k or so).
FWIW
Thanks MR COFFEE
I know not much about ICs and stuff. I was trying to know what a bipolar input stage is, or what a jfer or fet input stage is, but I can't find any info about it.
So, I have a bass with 2 asb5 from seymour duncan basslines, wich are active pickups, but I don't know if their output is high or low impedance ....
and this schematic is for passive pickups with hi impedance , but it says MC33.... (forgot the name of the IC) ... and the TLE2142 is a direct replacement in the TI list.
I would appreciate if you could help me with this too.
Thanks for you attention and patience.
Gabriel
I dont´t know whether the input stages are important for this circuit. One feature that makes the MC33178 attractive is the low supply current that is roughly 1/10 of a NE5532 or OPA2134. Therefore, your battery should last much longer.
Please correct me if I am wrong.
Markus
I added a stereo plug on the output and added a 9v supply line in the first pedal my signal runs through, so no battery is needed. I used a XLR cable (three lines) and stereo plugs.
QuoteI added a stereo plug on the output and added a 9v supply line in the first pedal my signal runs through, so no battery is needed. I used a XLR cable (three lines) and stereo plugs.
I was thinking too to try this approach. So the first pedal could also simply be a power supply box with either 9V or maybe even 18V and just a stereo input plug and a mono output plug. I suppose it just has to be a good regulated ps without any ripple. Othrwise there would be hum.
Hmm, may be I will upgrade to this version once my NTMB clone is working.
BTW, Bernadduur how's yours working?
Cheers,
Markus
Right now it is working like a charm. I need to experiment a bit with it because I get too fast too much gain and overdrive the amp a bit (also because I do not have a good bass amp (will change soon)). I made the trimpot accessible on the control plate (screwdriver) so I could change that when I play through different amp (I organise jamsessions and therefor play a lot through different amps). Here are some pics:
pic 1 (http://www.student.kun.nl/r.kerkhof/1/1.jpg)
pic 2 (http://www.student.kun.nl/r.kerkhof/1/2.jpg)
pic 3 (http://www.student.kun.nl/r.kerkhof/1/3.jpg)
pic 4 (http://www.student.kun.nl/r.kerkhof/1/4.jpg)
pic 5 (http://www.student.kun.nl/r.kerkhof/1/5.jpg)
pic 6 (http://www.student.kun.nl/r.kerkhof/1/6.jpg)
pic 7 (http://www.student.kun.nl/r.kerkhof/1/7.jpg)
pic 8 (http://www.student.kun.nl/r.kerkhof/1/8.jpg)
pic 9 (http://www.student.kun.nl/r.kerkhof/1/9.jpg)
pic 10 (http://www.student.kun.nl/r.kerkhof/1/10.jpg)
pic 11 (http://www.student.kun.nl/r.kerkhof/1/11.jpg)
pic 12 (http://www.student.kun.nl/r.kerkhof/1/12.jpg)
QuoteRight now it is working like a charm. I need to experiment a bit with it because I get too fast too much gain and overdrive the amp a bit (also because I do not have a good bass amp (will change soon)). I made the trimpot accessible on the control plate (screwdriver) so I could change that when I play through different amp
Great to hear that it works. Nice pics! Congrats!! :D So obviously my tracing work produced something useful. One Q: with the switches do you change only midrange caps or also other tone control caps? Do you prefer any other setting over the stock version?
One comment regarding the trimpot. IIRC it was set to about 50% on my original unit which gives you about 2-fold gain at all tone-controls flat.
I already got some pots that fit into my bass but I'm still waiting for some other parts (the austrian mail is terribly slow :( ). Since I now know that it's working I am even more keen to rebuild mine (I had a few bugs in my layout).
Markus
I found a schematic on the Bartolini site for a midrange switch with 3 stages that shifts between 3 different mid settings. It is really useful. Other switches are active / passive and series / parallel for the two pickups.
Hey Bernardduur,
Did you use the original schematic or the modded one ?
As i told markusw before, next week I will try to build only the eq stag and maybe skip the gain one .. so I guess I won't face this gain problem ... and if I need it, maybe I can do what you did, use the gain stage, since I have a volume/blend stack pot, and room for an othe one, who would be gain ...
I'd like to know 2 things ... could I mix the 2 pickups signal and use a single opamp ?
I cant find tantalum caps, would the sound get too different if I use eletrolitic ones ?
Hmm, I have no modded ones. I just use the schematic as on the first page here and added some "extra" features by searching the Bartolini site where they offered some (three position switch, etc.).
You could mix the 2 pickups signals; when I am correctly every time you use 2 or more pickups you mix some pickup signal. A stacked pot would be decent, but I could not find any dual concentric pots (or they costed me an arm and a leg) so this was the only way possible.
Second, the unit would sound different with using elco's instead of tantalum caps because the elco's have a bigger leakage and would affect the sound; I would not know how much and how it would sound. I just got the tantalum for very cheap so I used them.
QuoteAs i told markusw before, next week I will try to build only the eq stag and maybe skip the gain one .. so I guess I won't face this gain problem ...
I was just browing through the other thread. Actually I'm quite sure that it really does not matter whether your pus are active or passive. If you build the orginal version with the gain stage included (which is just a few caps and resistors more, and the second half of the opamp is used too) you can simply turn the trim pot down until youre unity gain. Or even easier, ommit the trim pot as well as the three resistors in the feedback loop of IC1 and connect "neg in" with "out". You then can connect your active pus to the input of the original schematics via your blend pot. If you keep the trimpot you're a bit more flexible if you once decide to use passive pus.
I just believe that blending the two pus with a single linear pot will give you a different blending feel than with a MN taper or a log/antilog and probably you won't be able to have 100% pu1 or 100% pu2 signal. But I really may be wrong with this.
Regarding the tantals, maybe you can get the via mail order. In Europe Conrad, RS comp,...... carry them.
Markus
The blend is very different than with a MN pot; for best blending use two pots or a MN pot.
Hey ... here in my city (Salvador , in Brazil) ... it's impossible to find a polarizes 820n cap .... some people laugthed at me today .... and the inductors too ... kind of impossible ...
Would you guys recomend any other mid section from an other pre amp ???
Thanks ...
Gabriel
ps: if I can not find em ... could I just skip that mid section and use treble and bass ?
Come on guys ... I have all the other parts but if I can't build this without the stuff for the mid control I will send them back ... =)
give a hand here
Sorry for the delay. I`ve used two MKS film caps in parallel : 0.33µF and 68nF which gives approx. 398nF.
The two 820 nF caps in series give 410 nF, so it's close enough. I doubt one will hear the difference especially since the tolerance is between 10 and 20%. If you want to be more exact, measure some caps and use the ones that give you 410n.
Good luck,
Markus
PS: BTW I also replaced the two 22µ tantals with the 2700 resistor between them as well as the 10µ output cap with a 10µ Wima MKS.
Ah, I had some laying around so I had no trouble in finding those hard to find caps. Luckily you can "cheat" a bit by putting things in series or parallel as I should have advised.
The biggest problem here is to find the inductors .... almost impossible :( ...
I will try to build this thing without the mid section .... and see what happens ....
thanks for everything
Gabriel
Use three 100 mH inductors or 6 50 mH or so. I had some problems but it took some looking around here.....
Second, the mid section in my unit is very important; with this setting I can easily overload my amp or get a nice rock-bassy sound. I don't know, I use that knob the most (bass and treble are most set in one position).
I also had to use 3 100mH coils. I don't think it makes a difference.
BTW, Gabriel you've got PM.
Bernardduur, two Q: IIRC you've used the OPA2134. Did you use the 25.5k R in the voltage divider or did you use two 30k? What Vref do you get?
Markus
25.6k (made it with some other resistors). I don't know the Vref I got.... I once measured it and found it was quite low but all works fine so I don't mind. Will measure it later this day.
QuoteI once measured it and found it was quite low but all works fine so I don't mind.
Although I built a modified version with two separated input buffers and therefore used two opamps I had similar results:
25.5k
a: with two NE5532, V+=8.48V Vref=3.22V
b: with two MC33178 V+=8.55V Vref=4.08V
2x 30k
a: 2x NE5532 V+ 8.48V Vref=3,51V
b: 2x MC33178 V+ 8.60 V Vref=4,47
Would be interesting to see what you get with a MC33178.
Please correct me if I'm wrong, but all this makes me believe that the 25.5k is not for lowering Vref, but probably to adjust it to V+/2. :?: :?: :?:
Any explanations because I really don't understand this?
Markus
I measured it and these are the outcome:
- 8.96 volt as V+;
- 4.07 volt as Vref.
Enjoy these measurements.
And I don't know why it is used; I don't mind also because it functions :D
BTW, did you use 2 IC's??? Was a dual IC not usuable?
QuoteI measured it and these are the outcome:
- 8.96 volt as V+;
- 4.07 volt as Vref.
Enjoy these measurements.
And I don't know why it is used; I don't mind also because it functions
Thanks for your measurments. I really enjoyed them :wink:
Of course, the most important thing is that it works, but it does'nt hurt to know whats going on, does it?
QuoteBTW, did you use 2 IC's??? Was a dual IC not usuable?
Modfever. On the Bartolini hp I saw that they also have variants with two separated buffers.....therefore I needed another IC. Frankly, I don't know whether the two-buffer version changed the sound. I just know that it works, and that like with my original unit it's pretty easy to find a sound I like.
Markus
Ah, OK. I understand. Could the measurement also different because of the fact I use a 9V obtained from a PSU, not a battery?
http://diystompboxes.com/sboxforum/viewtopic.php?t=33107
Quotehttp://diystompboxes.com/sboxforum/viewtopic.php?t=33107
I know :oops:
Sorry, but I did'nt understand it. Although I basically can imagine what you meant I'm unable to say whether this might be the case for this circuit or not.
When you look at the schemo is it possible to check whether the positive half of the phantom gnd draws more current than the negative half? I'd be more than happy for an explanation for dummies (if it's not too complicated). Thanks a lot in advance.
QuoteCould the measurement also different because of the fact I use a 9V obtained from a PSU, not a battery?
No idea :?:
BTW here is my modded schemo:
Markus
(http://img.photobucket.com/albums/v21/markusw/NTMBmodf5.jpg)
Nice one. Two individual gain parts for both pickups and then mix the sound of it. I like it. Wish I had more space in my control cavity.
No, I am happy with the unit I have right now :D
Quote from: BernardduurNice one. Two individual gain parts for both pickups and then mix the sound of it. I like it. Wish I had more space in my control cavity.
No, I am happy with the unit I have right now :D
Actually I don't think it makes a huge difference with the two buffers, especially since the pickups I'm using are the same type. As I said..modding fever. Anyway, I happy too with it. IMHO the most important part is the tone control. According to my Spice simulations the EQ bands are rather broad. This might explain why it's so easy for me to get the tone I like. Please correct me if this is rubbish.
From the pics you've posted however I think there should be enough space in the cavity of your bass to allow the addition of a second opamp and the few other parts, just in case you get the modding fever :wink:
BTW, as soon as my digicam has new batteries I will post pics of my version, but basically it looks the same as on the pic in this thread http://diystompboxes.com/sboxforum/viewtopic.php?t=33729&start=0&postdays=0&postorder=asc&highlight=ntmb
Markus
like I mentioned in the other thread weeks ago,
I think there is an unequal current draw on both "halfs",
and that`s probably the reason for the unequal divider:
so in the end, Vbias will finally be half Vsupply.
Quote from: puretubelike I mentioned in the other thread weeks ago,
I think there is an unequal current draw on both "halfs",
and that`s probably the reason for the unequal divider:
so in the end, Vbias will finally be half Vsupply.
Thanks a lot!! Is it obvious (at least for someone with more knowledge than me) from the schemo, that there is an unequal current draw? Sorry for the dumb questions. :oops:
Markus
Nice pic. You used the same inductors as I did.
Quote from: BernardduurYou used the same inductors as I did.
Yup, I noticed :) Could'nt find any 150mH.
Markus
Mouser has 150mH inductors available.
Does anyone feel like sharing their PCB layouts for this?
I just did a layout for my modded version. See pic in http://diystompboxes.com/sboxforum/viewtopic.php?t=33729&highlight=ntmb It was done for my Carvin bass.
As you can see it has several micro dip switches I justed added because there is plenty of space in the cavity (and of course for checking the influence of different cap sizes mainly in the tone control section). Also, the distance between the pots is tailored for my Carvin.
In summary, I doubt that it will be of any use for you. Bernardduur did the original version on vero. Maybe ask him for a layout. He also did not use any PCB mounted pots. Therefore, it's a lot more flexible than my layout. What bass do you want to put it in?
If you nevertheless want my layout just drop me a pm.
Markus
Well, I WAS looking for a more generalized layout... My bass is most likely not one you've ever seen, or heard of, for that matter.
I guess I was just being lazy, anyway. It's not a terribly complex circuit, I should be able to make my own layout without too much trouble.
What bass are you playing then? Now I am curious.
Sorry, didn't mean to be enigmatic :)
It's an Alfredo Bugari Stonehenge. I Added an EMG-40P active to it, sounds great.
Can i use NE55323s in this circuit?
Wow, I never heard about that bass.
And yes, you could use a NE5523 but I would not know how it would sound as my OPA IC must sound different than the stock IC's.
Quote from: ejbassesCan i use NE55323s in this circuit?
When I first fired up my modded NTMB I put in 2 NE5532, to avoid killing my MC33178 just in case some was wrong. I had several NE5532s laying around and just two MC33178. Also the MC33178 are more expensive here in Austria. It worked the same with the NE5532s. Soundwise it should be at least equal to the MC33178.
Two comments regarding the NE5532:
1) it will draw much more current from the battery than the MC33178 (roughly 8-10 times). So your battery will be empty much faster, unless you go with a "phantom power" cable like Bernardduur did.
2) Vref most likely will be lower if you use a NE5532. So you might want to put in a 50k trim pot instead of the 25.6k resistor in the voltage divider. This would allow you to trim Vref to V/2 (depending on the opamp you're using).
Good luck,
Markus
You own a Stonehenge??!? As in Castelfidardo? That's truly an axe to be reckoned with!! :D
Wow, someone else has heard of it :)
I picked it up at a music shop in town for $350 US. Got lucky.
Markus,
What would happen if my Vref is a little bit lower? When you used NE5532 did you change anything in the biasing? Current consumption wouldnt be much of a problem to me because i plan in using it as a stompbox.
Quote from: ejbassesMarkus,
What would happen if my Vref is a little bit lower? When you used NE5532 did you change anything in the biasing? Current consumption wouldnt be much of a problem to me because i plan in using it as a stompbox.
You simply have a little less headroom. Most likely you won't hear any difference unless you set the gain trimpot rather high and your pickups have high output (e.g. active pus). The Vref trimpot would it make just a bit easier to test different opamps while having Vref set to V/2 (which usually means most headroom). If you put it in a stompbox the NE5532 for sure is fine.
Markus
In the schematic, I see that C5 and C6 are polarized, but they're really tiny, and according to the note, they should be ceramic. Was the polarization just an error?
Also, the "off" resistance of the push/pull... Don't see anything like that in Bartolini's wiring diagrams. Also, the value of the gain trimpot is 5k in the Bart docs. Is this just an older revision of the preamp?
Sorry I was not clear enough. C5 and C6 are tantals too (they are nearly µF :D). I replaced them with two film caps in parallel (0.33µ + 0.068µ). Honestly, I don't know whether my unit is older than the diagram on the Bart hp (I bought it in 2001), I just know that the trimpot in my unit was 10k (as indicated in the schemo), and there were two 47k resistors soldered to the push/pull switch (I suppose to prevent popping).
Ok, I read C5 and C6 as 820p instead of 820n... Don't know why :)
Anyways, I'm working on my own PCB layout of this thing (hence all the "brilliant" questions) and I've run into a few more questions:
Is the signal routing terribly crucial? That is, should I take pains to keep the input and output lines physically distant? I know it's not a distortion unit, but there IS some gain in this, so I thought I'd ask.
What about using an MC33078 for the opamp (seems the best equivalent that Mouser has)? I haven't checked the datasheet about the whole asymmetric v-ref thingie yet, but if it's different, I could just compensate by making the v-ref v/2 (or whatever is called for), right?
What about substituting silver-mica caps for the ceramics? Judging by the capacitor comparison table in "The Art of Electronics", this would be a good thing, right?
Lastly, has anyone else done a single-board layout they'd like to share? :)
I'm also toying with the idea of making a surface-mount board. We'll see how far I get :)
I don't think that the signal routing is terribly crucial because the gain is not that high. However, if you can manage to keep input and output physically separated it wont hurt.
Regarding the MC33078, it has about the same power consumption as a NE5532 or OPA2134. So there wouln'nt be any benefit in this respect. IMHO the MC33178 was primarily used in the original Bart unit because of it's low power consumption (your battery simply lasts 8-10 times longer compared to a NE5532 or OPA2134). If I'd put it in a stompbox I'd go with a OPA2134 or NE5532 (btw I'm really curious if you can hear any difference once your build is done) and adjust Vref with a 50k trimm pot.
Silver-mica for sure is fine, I've used Wima FKP and MKS films.
Question: What do I gain or loose when I put the preamp in a pedal sized box instead of my bass; right now I have purchased a second bass (different setup / tuning / etc.) but to build the unit again as I can share them by adding the preamp to a box. Ant thoughts on this?
this would be worth a new thread: active guitar/bass... (pros & cons)*
you loose the ability to drive long cables to your rig,
and you loose some high frequency content;
you could load your pickups with some "tonesucking"...
you gain the easier battery replacement/powersupply;
and you gain the advantage of more universatility
to plug your axe wherever you want it...
(there may be different/additional opinions, though)
[EDIT]: * NEW THREAD HERE: :) (http://diystompboxes.com/sboxforum/viewtopic.php?t=34520)
Ah, thanks for the linking. I thought it would be a bit too much attention getting from my place (I am humble)....
Does anyone know why:
Resistors
R10 through R12
and Capacitors
C9 through C13, and C18
are not on the orignal schematic (the unmodded one). Or Am I missing something?
Thanks,
Adam
Quote from: bassist4God770Does anyone know why:
Resistors
R10 through R12
and Capacitors
C9 through C13, and C18
are not on the orignal schematic (the unmodded one). Or Am I missing something?
Thanks,
Adam
When I did the schemo it took some time (and some corrections/deletions) until it was correct, and I simply did'nt renumber the parts. So nothing is missing.
Markus
Thank you very much man. I was thinking that was what happened. Anyways i'm off to order my parts for it. I'm sure you will be hearing from me again. lol.
Thanks,
Adam
What diode did you guys use? I'm not so sure on all the substitues and stuff.
I used a 1N4002 diode for the powersection.
Will these inductors work for this preamp?
http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=269540
Just wondering seeing as how you guys were using different ones.
Thanks,
Adam
Quote from: bassist4God770Will these inductors work for this preamp?
http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=269540
Just wondering seeing as how you guys were using different ones.
Thanks,
Adam
What I can see from the data sheet, they look exactly like the two on my original unit. I just could'nt find any 150mH, so I went with 3 100mH Toko inductors. They are magnetically shielded, which I assumed should'nt hurt.
Markus
Cool.
As far as I know there are only 2 resistor values that I can't find. I just want to double check and make sure these are right.
From the Unmodded circuit( R2 = 25.6K ohms and R15 = 6590) are these the correct values for this circuit? If so did you guys find resistors at those values are did you chain some together?
Thanks,
Adam
Quote from: bassist4God770Cool.
As far as I know there are only 2 resistor values that I can't find. I just want to double check and make sure these are right.
From the Unmodded circuit( R2 = 25.6K ohms and R15 = 6590) are these the correct values for this circuit? If so did you guys find resistors at those values are did you chain some together?
Thanks,
Adam
You could replace R2 by a trimpot (50k) and adjust it until Vref = V/2. Using a trimpot instead of R2 might be an advantage especially if you intend to use an opamp different from MC33178 (see the previous posts). Regarding R15, I don't think that the exact value is terribly important. Changing the value will just slightly alter the available gain range of the input stage. So something in the range from 6000 to 7000 should be OK.
Good luck,
Markus
Ok that is what i was thinking Markus. I've placed my order through Mouser and Small Bear. Hopefully I will be able to get started on it next week.
Also, wondering if you could help point me in the gerneral direction on how to make a layout for this circuit. I have FreePCB, but i'm not real sure on how to do this. Thanks for your help once again.
Thanks,
Adam
I made the exact values by using multiple resistors (max of 2) and all could be made this way. Don't know if it sounds any different though.
Hello.
What if I used 2 individual volume pots, one for each pickup, how could I "plug" em in the preamp ? can I just solder them 2 or do I need to create 2 individual buffers ?
> What if I used 2 individual volume pots
Take the output of your two volume pot configuration, then connect that to the junction point of C14 (100n) and R13 (1500k). You can remove pots U5 and U6 on schematic. You could possibly experiment by removing R13 for a tad more highs - this is entirely up to your taste.
Thanks!
I did not know if I could just solder the 2 cables together and then put the signal right to the board!
Thats the problem that computer scientists face when trying to figure out how to play with electronics hehehe :D
Thanks for the tip!
Gabriel
Hello all!
I´m glad to say that I finally built this unit!
I have a bass with 2 emg 45j pickups and an emg bqt system ... and it sounds great for solo stuff, clean and clear .... but it lacks punch, and could sound fatter, with more presence and warmth ...
This unit gives me that sound .... even in flat mode (it doesnt sound flat) you can get a lot more punch and presence .... comparing to the sound without the ntmb ... and I´m not only tlaking about volume.
But there are some things that I do think are not working properly:
The bass pot is a linear 50k pot? Because I´m using it and I can see it boosting or cutting only in the first and last 15% of the pot, and no effect or almost no effect in the 70% in the middle.
The other pots have this problem too put not "strong" as in the bass pot. I can notice for example that the treble pot gives me some difference but in the 15% end for boost I get a very very cristal sound .... and I can notice is going away like an on/off thing when I turn the pot backwards ..
When I play with the eq section I get a BIG volume difference, what gives me the impression that each eq band is kind of "big" and when I boost or cut I boost or cut a lot of frequencies (I hope you can understand it). Is that the way it works ?
I did a prototype, because the pcb is still rustic .... so I soldered the mid section with c7 (100n) just for testing .... is that mid the hi mid ? because I get an impression that when I boost mid to the max I get a lot of treble too! Man, I dont klnow if thats because Im used to emg .... but my actual pre (emg) only boosts and cuts a small range of frequencies ... and I dont get those problems.... so I´d like to know if without the 100n c7 cap I would get a bassy mid.
Thanks for your attention and help,
Gabriel
Hi Gabriel,
congrats for your build :)
All three tone control pots are 50k lin.
QuoteThe bass pot is a linear 50k pot? Because I´m using it and I can see it boosting or cutting only in the first and last 15% of the pot, and no effect or almost no effect in the 70% in the middle.
The other pots have this problem too put not "strong" as in the bass pot. I can notice for example that the treble pot gives me some difference but in the 15% end for boost I get a very very cristal sound .... and I can notice is going away like an on/off thing when I turn the pot backwards ..
Your impression is correct: all three pots have less influence on tone when they are close to 50%. The more you turn them away from 50% the stronger their effect gets, although I do not have the impression, that they have no effect when they are close to 50%, it's just more subtle.
QuoteWhen I play with the eq section I get a BIG volume difference, what gives me the impression that each eq band is kind of "big" and when I boost or cut I boost or cut a lot of frequencies (I hope you can understand it). Is that the way it works ?
Yup. The NTMB has pretty broad bands. Thats why it's easy to get the sound you want (at least this is my explanation).
Quoteso I soldered the mid section with c7 (100n) just for testing .... is that mid the hi mid ?
Thats around 1000 Hz.
Quotebecause I get an impression that when I boost mid to the max I get a lot of treble too!
1000 Hz plus a quite broad band also gives you some highs when turning up the mid pot.
One Q:Â the two 820 nF caps in the mid section are present in your circuit?
Forgot before: have a look at the Bartolini page. There you can find a table "mid freq cap (c7) versus center freq". To get the mids more bassy try with a 220nF or even a 470nF cap for c7. Without the c7 cap it might be too bassy. Just start experimenting until you find your optimum. Thats the fun, is'nt it??
Regards,
Markus
I just new to this forum and just created NTMB clone... just wondering if someone can guide me how to make mid-sweep??? Simply pararel the cap with mid-sweep pot ??
I've done the clone, use it with my squier P-J bass. I replaced P bridge pup with musicman style pup.
I've found that the clone cuts some treble (high) frequency. If i bypass the clone, the sound more bright (a lot of high freq).
Response of the 3 control pot are the same with Gabriel just mentioned, the mid pot also affect with the high freq.
Is this normal ??? I'm not using the output (25K) pot, just conect directly to amp.
Quote from: kriwil on April 30, 2006, 10:05:36 PM
I've found that the clone cuts some treble (high) frequency. If i bypass the clone, the sound more bright (a lot of high freq).
Response of the 3 control pot are the same with Gabriel just mentioned, the mid pot also affect with the high freq.
Is this normal ??? I'm not using the output (25K) pot, just conect directly to amp.
I did not observe the treble loss, sorry. Also I don't have any idea why it should occur. Frequency response is linear over a wide range.
Pot response is as mentioned.
Markus
acctually, i'm not to sure for the treble loss... Is this the way it does or not... I've tried do the simulation using LTSpice freeware, somehow, there is no pot available in the library... I cannot do the simulation... :(
Could u sent me the file for LTSpice to do the simulation?? or, may be you can post the result graph for simulation with original schematic.
He Kriwil, just to answer your PM;
I also had no issues with any treble loss. I really liked the circuit and used it a lot back in the days I still had it........
Quote from: kriwil on May 01, 2006, 06:53:21 AM
acctually, i'm not to sure for the treble loss... Is this the way it does or not... I've tried do the simulation using LTSpice freeware, somehow, there is no pot available in the library... I cannot do the simulation... :(
Could u sent me the file for LTSpice to do the simulation?? or, may be you can post the result graph for simulation with original schematic.
I'm in a bit of a hurry right now, but you can download pot model files and a lot of other useful stuff (e.g. a Vactrol model) at the LTSPice yahoo news group. You can find it easily with googling. There is also an explantion on how to use these pot models.
If you can't find it I will send you the LTSpice file later, but I can assure you the EQ response is flat (smaller than 1dB) from 20Hz to 10kHz.
Regards,
Markus
Quote from: Bernardduur on May 01, 2006, 07:12:09 AM
He Kriwil, just to answer your PM;
I also had no issues with any treble loss. I really liked the circuit and used it a lot back in the days I still had it........
I believe you are using the original schematic as well. Then something wrong with my clone... I need to check again.
something wrong with the treble section.
I have check my clone, i tried to bypass the eq section. I connect directly from first op amp output (C15). The sound somehow different with the original sound (passive mode).
Will trace the pcb route again... may be something is not routed properly.
I just found that i put the wrong value of 68p cap. Now, the clone works perfectly. The sound is awesome......
Thanks markus and bernardur....
Quote from: kriwil on May 02, 2006, 10:55:04 PM
I just found that i put the wrong value of 68p cap. Now, the clone works perfectly. The sound is awesome......
Thanks markus and bernardur....
Cool :icon_cool:
Markus
Nice!
wow thank you guys! ;)
Where can I buy the inductors? ???
smallbear only 1h, 220mh and 470mh
have a nice day!
please someone can help me :icon_cry:
RS Components? Mouser? eBay?
At Conrad Electronics they have a diy inductor kit (core and winding wire) maybe that's an option. You need 3x100mH right? If you wind yourself you can make it a tapped inductor. I do wonder about the physical size of the core being offered at Conrad, maybe it's too large to fit in an instrument.
thanks ;)
hhttp://ar.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=1911226
Is this inductor for NTMB?
leandro.
Your link doesn't work, so there is no way to tell ;)
µicro not milly :icon_wink: (http://ar.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=1911226): µicro:small/milly:big!
Hello everyone.
I was wondering if I could use 3X fastron inductors with 100 mh ?
here's the data sheet:
(http://img268.imageshack.us/img268/7200/bartoliniinductory.th.jpg) (http://img268.imageshack.us/i/bartoliniinductory.jpg/)
150 micro H, or 150 mili H?...
I have found 150 micro, but in the electronics shops here nothing more than 2,7 milli H
Hi, Does anyone have the layout of this project Bartolini NTMB?
thankyou.