I've been digging into the Timmy circuit lately and came across this site (https://manticorefx.wordpress.com/2017/10/26/timmy-versions/) that documents a few of the changes over the years. None of the schematics I've come across show any of the improvements that have been made - they all seem to be of the first iteration. Most things described are easy enough to follow, but one I'm not 100% sure about.
The page references a Paul C. post at MadBean where he wrote:
Quote from: paulc link=http://www.madbeanpedals.com/forum/index.php?topic=23478.msg231150#msg231150
The output stage had it's values changed from the stock 2x 3k3 w/4n7f setup to 2x 10k w/2n2f.
The 2x 3k3 in the output stage is shown in the "Timbre Reamer" schematic at the top of the manticorefx page - this is the schematic that all others seem to be based on. But there's no 4n7 cap in the output stage (or anywhere) in the schematic. If you look at the various gut shots and read the descriptions, the 4n7 cap doesn't show up until "v3" and in later gut shots you see a 2n2 in the same position.
I'm fairly sure that this cap must be between the op-amp output and inverting input, parallel to the first 3k3/10k - to smooth out the top end. I can't see it being in series with the second 3k3/10k to ground since that should cut an extreme amount of bass. Does that make sense? Or could it be somewhere else?
I claim no prior knowledge regarding the Timmy details but based on links you gave, the web pages and the posts I think the idea is this:
- the schematic is for the hand-build one, which defaults to V1
- as you go down the page the changes in each version are elaborated.
So from what I can see the cap at the output stage is not present on V1 and so it is not present on the schematic, which is for V1. However I can clearly see the parts 10k, 3k3, 2n2, 4n7 on the boards as you go down the page.
So I guess the beef is there's no cumulative log of the changes captured on the schematic.
The other changes are:
- treble pot taper change
- 39nF input cap change
- dip switch removed
- 47pf input cap
I don't know about the feedback circuit I've seen on one of the schematics.
I built it using the tagboard layout. I always thought it was accurate, but these update... we whould track it again! :o Or maybe update the schematic reading all the information we can read in that page GGBB linked us.
QuoteI built it using the tagboard layout. I always thought it was accurate, but these update... we whould track it again! :o Or maybe update the schematic reading all the information we can read in that page GGBB linked us.
I read over the manticorefx site and many of the posts around on the internet. The manticorefx site covers pretty much everything except the year the changes occurred and perhaps the colors of the boxes.
Paul Cochrane has been very open about the changes he has made over the years.
Most people on the internet call the earlier model without the toggle switch V1, regardless if it was the PCB version or the veroboard version. I think it's better to stick with that or call the vero V1a and pcb V1b.
One thing I can add is V2 (Manticorefx V3) has the toggle switch.
The toggle switch is 3 positions:
Up = Assymetrical ; don't know which polarity is 2 diodes and which is one.
Middle = Symmetrical Low Compression; 4 diodes, two up/ two down
Down = Symmetrical Most Compressed; 2 diodes, one up/one down
V1 has a no toggle switch and it has dip switches inside switch the diodes. This configuration has two assymetrical modes, which probably sound identical. I don't know which way the assymetrical diodes go on V2.
Also the version of the schematic on the web with the toggle switch is the V1 circuit where someone has added a feedback path (like Fulltone). This is a DIY circuit and the switch does not do the same job as the switch on the Timmy V2.
From what I can see V1a, V1b and V2 were available in the purple/blue color. After that they boxes changes color. I don't know if the color corresponds to the circuit changes.
Quote from: GGBB on December 07, 2018, 12:24:31 AM
I'm fairly sure that this cap must be between the op-amp output and inverting input, parallel to the first 3k3/10k - to smooth out the top end. I can't see it being in series with the second 3k3/10k to ground since that should cut an extreme amount of bass. Does that make sense? Or could it be somewhere else?
There is a possibility for 4nF cap to be in place of 10nF cap (C7) 'cause that's the closer value
existing cap on output stage..(although it makes no obvious sense to alter C7 value when altering feedback/gain resistors values..)
(can't recall neither the origin of the bellow schematic nor its version.. :icon_redface:)
(https://i.imgur.com/4jR2wzr.png)
QuoteThere is a possibility for 4nF cap to be in place of 10nF cap (C7) 'cause that's the closer value existing cap on output stage..(although it makes no obvious sense to alter C7 value when altering feedback/gain resistors values..)
(can't recall neither the origin of the bellow schematic nor its version..
Your schematic is the early V1 schematic.
The V2 (manticorefx V3) circuit adds a feedback capacitor across the output and -ve input of the opamp to give it a bit of roll-off. Later on he changed the 3k3 to 10k and reduce the feedback cap to 2n2. (PC said it doesn't change anything but the scaling of the parts does shift the pole/zero frequencies).
The 10nF treble cap remains in all cases.
I don't want to draw a new schematic now, but I can show this schematic because it has some useful indications:
(https://1.bp.blogspot.com/-qmzOMobAhcw/VjeM8_IXohI/AAAAAAAAB3I/tCCq1zhZQC4/s1600/JANRAY%2BANALYSIS%2BCoda%2BEffects.gif)
So, the two 3.3k resistors in the last stage are now 10k, and if those indications are true increasing these resistor we should increase and decrease at the same time the volume, getting kind of the same volume?
And the new cap, 4.7nF early and 2.2nF now, goes in parallel with R6 (in the schematic I linked above).
Is it alright?
QuoteI can show this schematic because it has some useful indications:
FYI, that schematic is OK for the general circuit shape but it has a *heap* of values which don't agree with the real thing. The schematic antonis posted is much closer. If you take antonis's schematic and put a 4n7 cap across the resistor R9. Then put a switch on the diodes you would be getting pretty close.
QuoteSo, the two 3.3k resistors in the last stage are now 10k, and if those indications are true increasing these resistor we should increase and decrease at the same time the volume, getting kind of the same volume?
And the new cap, 4.7nF early and 2.2nF now, goes in parallel with R6 (in the schematic I linked above).
Is it alright?
That's pretty much it. The cap would be C8 in your schematic. All units which had the 3k3+3k3+4n7 to 10k+10k+2n2 change also changed the treble resistor from 1k5 to 1k0 (R7 in antonis's schematic, R5 in yours). The 10k version has a little more roll-off at the opamp so Paul C shifted the treble cut-off frequency up so it sounded the same overall.
The only reason I'm interested in sorting this out is I've had all the different schematics sitting on my computer for several years. I was pretty sure many were not the real thing.
I'd stick with the schematic antonis posted and update that. Then use the manticorefx site to guide you to whatever version you want. There's all the stuff about pot taper changes and adding resistors across pots. It's all on that site.
If you want to be precise, there some minor differences in the schematics that need sorting out:
- On the later versions are the up and down diodes are cross-linked? like in antonis's schematic.
- On any of the versions, does the outer lug of the bass and treble control connected to the wiper.
- Which way the bass and treble controls pots work: As far as I can tell, for the V1 circuit, when the bass and treble controls are rotated clockwise the bass is *cut* and the treble is *cut*. So from this perspective the bass pot on antonis's schematic is reversed (and the JAN RAY one you posted). I have another schematic which has it going the "correct" way. I don't know if this has been changed on the later versions.
- I'm pretty sure V1 units used audio taper pots for both Bass and Treble.
- The V1 units have a slightly different control layout arrangement: the Gain control is top left and the Bass control is top right. On the later units these get swapped and the toggle switch is added in the centre.
EDIT: Here's the link about the pot tapers, but I have a feeling the linear Treble pot taper is for a later model:
https://www.diystompboxes.com/smfforum/index.php?topic=119910.0
Yes, see here,
"The only change that's really happened to the pedals is the taper of the treble control which you noticed in one. It was changed from a 50ka pot to a 50kb around July 2012. It was right after the 1st run of surf greens when I changed it in all the pedals. With the old audio pot the critical area was bunched up between about 11 o'clock and 3 o'clock with not much going on with the last couple of settings on each end. The newer taper spreads it out more making it start to roll off quicker, and slow down when it gets darker - not as touchy as before."
https://www.thegearpage.net/board/index.php?threads/timmy-version-question.1444785/
Thanks.
Yes, I posted the schematic just to have some indications about the parts.
I didn't noticed that extra 150pF!
And just to make the topic even clearer I can say that I built this:
https://3.bp.blogspot.com/-imI0JcQ_gSI/VAmT8yw-f3I/AAAAAAAAImM/MqxVruF6nCo/s1600/Paul%2BCochrane%2BTimmy%2BRev%2B2.png
Definitely the Treble and Bass pot work better if they are audio tape. Indeed, I ordered for a mistake two linear, but I could use just the first 30% about. And both the pots work like a "filter": you got max bass and max treble with the pots at minimum.
I have to look better the page you linked.
Then I built even the Jan Ray:
https://4.bp.blogspot.com/-Kl8c9Ob6p3g/U-vrtT1wGFI/AAAAAAAAIdI/JUibz5iBxD8/s1600/Vemuram%2BJan%2BRay%2BRev3.png
The layout wasn't exactly this, but Bass e Treble pots work commonly, indeed, they are connected differently from the Timmy layout.
QuoteAnd just to make the topic even clearer I can say that I built this:
https://3.bp.blogspot.com/-imI0JcQ_gSI/VAmT8yw-f3I/AAAAAAAAImM/MqxVruF6nCo/s1600/Paul%2BCochrane%2BTimmy%2BRev%2B2.png
Definitely the Treble and Bass pot work better if they are audio tape. Indeed, I ordered for a mistake two linear, but I could use just the first 30% about. And both the pots work like a "filter": you got max bass and max treble with the pots at minimum.
As is, it's kind of a V1 with the DIP switch replaced by the toggle. So it would need the 4n7 cap across the right-most 3k3 to make it like the earlier V2's; the first ones with the toggle switch.
As mentioned before, in later versions PaulC replaced the audio treble pot with a linear. Linear treble pots are for units since July 2012. From what I can see he hasn't added any parallel resistors on the linear Treble. There's an extra resistor on the PCB for the LED, which I believe is for the LED, and the value changes a lot. Some of the later PCBs have yet another resistor, located near the LED resistor, which was part of the 25KA +18k resistor Volume pot change; used since around 2015.
FWIW, I prefer log pots (backwards operating) or reverse log pots on those circuits. If the frequency range is small then you can get away with linears.
Thanks Rob for all the details and everyone for participating. Based on this and the trail of Paul C's posts noted in the manticorefx page, here's an updated schematic I'm labeling "2014" since that's the date of Paul C's post about the volume control change. If anyone spots an error please let me know.
(https://i.postimg.cc/f3WYV0p9/Timmy2014-Schematic-Rev-A.png) (https://postimg.cc/f3WYV0p9)
EDIT: Drawing revised with corrections noted by Rob
I have a layout for etching if anyone is interested (not yet verified).
Awesome. Thanks!
QuoteI'm labeling "2014" since that's the date of Paul C's post about the volume control change. If anyone spots an error please let me know.
What I've discovered is the manticorefx site bundles the cap changes because PaulC posted them together but in production they didn't occur together. The 39nF cap change occurred earlier. The 47pF cap change is more difficult to narrow down.
This is my best efforts at the dates:
- Linear treble pots are for units since July 2012
- LM1458N Mid(to Late) 2012 to Late 2014. After that Reverts back to RC4559D
- 39n cap change in Aug 2016 PaulC says "That was done years ago"
There's units with PCBs that have no holes for the RF cap but have 39nF and 1k treble.
There's also units with 47n and PCBs with holes for RF cap but there is no cap loaded.
I suspect the 39n vs 47n might have joggled about for a while.
- RF cap probably a bit after the 39n.
Anyway I fixed a few bugs:
(https://i.postimg.cc/Xr22FF0w/Timmy2014-Schematic-V10-GGBB-fixed.png) (https://postimg.cc/Xr22FF0w)
EDIT: On this I can add.
I haven't seen a unit with the 18k volume resistor that doesn't have the RF cap.
Provisions for the RF cap were on boards without the 18k resistor.
So if your schematic covers the 18k resistor we don't have to worry about when the
RF cap was implemented because it came before or at the same time.
The 25kA + 18k volume change was maybe mid 2013.
BTW the dude in my pic is the real Tim (according to PaulC).
Nice jobs, guys! ;)
All this update is for what? To roll off some treble or what else?
I didn't get if there's a reason to change a bit the volume stage. Just to get a better tape?
The tagboard layout show the 4559 as IC, but I didn't try it because I used immediately the 1458 just because some guys said that it sounds really good.
What difference could make the 1458 vs 4559?
Just for comparing, Jan Ray sounded to me with smoother treble (indeed, it has C4, looking at the new schematic, but I guess it could be even a question of the setting, and I want to remember that the Timmy has more gain than the Jan Ray because the Gain pot 1M instead 500k on the Jan Ray, even without count the "two diodes mode", of course).
But now I don't have the Jan Ray for an accurate test, because it was for a friend. Anyway it should be
Quotell this update is for what? To roll off some treble or what else?
I didn't get if there's a reason to change a bit the volume stage. Just to get a better tape?
I'm pretty sure the added cap is to take the edge off the nasty buzzy stuff around 5kHz and above.
PaulC did explain the reason for the volume mod. He wanted it to have unity gain when the Volume pot was at 12 O clock; not sure where the other controls are set.
QuoteWhat difference could make the 1458 vs 4559?
Changing the opamps changes the high-end character. It's very much a personal choice. You could put just about anything in there and try it, NE5532, TL072, ...
Someone was saying PaulC wasn't happy with the consistency of the sound of the 1458's. I don't know if that's true but I would not be surprised if some of the opamps these days sound different to the established "textbook" sound. I haven't bought one for ages. I have a lot of old stuff that has the "textbook" sound for each type.
Quote from: Rob Strand on December 08, 2018, 05:05:55 AM
PaulC did explain the reason for the volume mod. He wanted it to have unity gain when the Volume pot was at 12 O clock; not sure where the other controls are set.
I read it just now in a page you linked before.
Thanks Rob! ;)
Quote from: Rob Strand on December 08, 2018, 05:05:55 AM
Changing the opamps changes the high-end character. It's very much a personal choice. You could put just about anything in there and try it, NE5532, TL072, ...
About the IC I'll try some different next time! Maybe trying to replicate the newer version. :D
Quote from: Rob Strand on December 08, 2018, 12:00:45 AM
- flipped D1
Oops! :icon_redface: Good catch.
Thanks - my drawing (https://postimg.cc/f3WYV0p9) has been updated as well.
QuoteThanks - my drawing has been updated as well.
Good stuff, thanks! That should pin down what it really is.
FYI: While I was digging around I noticed from about mid 2018 there's units marked with '9-18Vdc' instead of '9Vdc' and also the Bass/Treble pots are being wired for clockwise = boost (which will probably require a reverse audio pot for bass). That's why I put July 2018 on my corrections.
Pin 3 of the gain pot is probably used (as shown in the schematic). I found,
PaulC Nov 2007: "The gain pot is wired in from both outside legs - the wiper is not connected in the normal way."
I found this interesting post by PaulC from 2007:
After elaborating much of the circuit in words. In the exact same thread he posted this in regards to someone posting the schematic.
" I'd rather it wasn't posted, but since i can't stop that I'd like it known it's not based on the reamer - it's based on the TIM which is 10 years old. These pedals are about half of the income my family has, and while you guys wont try to produce it for profit there are those that will. One guy already did last year , and had it up on ebay saying "looking for a Tim? Buy this - it's better". At least those guys should buy one from me to figure out instead of getting the info for free on the net. Is the right of the DIY guy to know more important than the finances of my family? "
In this 2018 thread where a schematic was posted he did not voice his objection and added more info
https://www.diystompboxes.com/smfforum/index.php?topic=119910.0
Should we remove the links or not?
About opamp types:
https://www.diystompboxes.com/smfforum/index.php?topic=108876.msg995229#msg995229
Note Mark Hammer, Reply #9 on: October 23, 2014 :
"A fellow in town, on another forum, brought his Timmy (actual, not a clone) over, and we experimented with different chips. he had read somewhere that the circuit liked the 1458. We tried about a half dozen different types - CA3240 (possibly 3260), TL072, OP275, 4558, LM833, NE5532, and MC1458 - and the 1458 took it, hands down, largely because it rounded off the tone a bit, complementing the bright sound the pedal normally had. I certainly wasn't expecting it to make a difference, but it did.
So why does the Timmy like a 1458 but the TS9 likes a 4558? The Timmy tone control is a high-cut only, and not the cut-and-boost type the TS has. It also has a higher clipping threshold. So I'm guessing the limitations of the 1458 compensate for the extra headroom, and also supplement the high-cut."
QuoteNote Mark Hammer, Reply #9 on: October 23, 2014 :
I tend to agree with Mark. The thing to notice about the Timmy is it has gain after the low-pass filter and the gain stage (x2) has no low-pass filter following that last stage. So if that stage clips you will be hearing the opamp. Things like the tube screamer and Xotic AC/RC have unit gain with only the tone-control giving opportunity for post low-pass filter gain. The BB is a little different as does have a post low-pass filter gain stage, however it's tied to the dual pot so it's only comes in at higher Volume settings.
After looking at Timmy with a clearer head, the low-pass filter added to the last stage on later versions doesn't filter the last stage if it clips so the opamp sound still gets through.
Some other well known "Transparent" pedals are the Clark Gainster (used opamp JRC072B) and Menatone Red Snapper (used opamp JRC4558D). These have a second gain stage but they put the low pass filter *on* the second opamp. So it's the same thing that second opamp has an opportunity to clip. The thing to note is these use different opamps. At the end of the day people tend to trim the high-end on the amp to compensate for the differences. When you do AB testing with the same amp settings the units with less low-pass filtering, or brighter opamps will always sound harsher.
Re the schematic and my previous comments:
- The units with the 18k resistor (which is what the schematic applies to)
always seem to use the RF cap and always use JRC4559D opamps.
- It's a bit fuzzy but from July 2013 the 18k might have been solder to the pot
- Then later on, say Jan 2014, the PCB was changed to incorporate the 18k.
- By July 2013 I'm pretty sure the LM1458N was removed from production.
The LM1458N was only used units without the traditional purple color.
So apart from a fuzzy region around July 2013 the V2 schematic never had LM1458N's
I've put together a Timmy *V2* "This is your life" document.
(It's attached to the post but you have to be logged in to get it.)
It's the best I can do with the info I have.
I don't think I will add to it. I'm sure it has some errors.
Use the manticorefx effects site link for pics. However I'm pretty sure it doesn't cover all the cases.
The version numbers in the doc are mine. It's the only way I could keep track of them.
(https://i.postimg.cc/TLRnsPY6/Tim-the-Enchanter-Monty-Python-The-Holy-Grail.jpg) (https://postimg.cc/TLRnsPY6)
Thanks! I love these kind of work. ;)
Quote from: Rob Strand on December 10, 2018, 11:27:16 PM
Re the schematic and my previous comments:
- The units with the 18k resistor (which is what the schematic applies to)
always seem to use the RF cap and always use JRC4559D opamps.
- It's a bit fuzzy but from July 2013 the 18k might have been solder to the pot
- Then later on, say Jan 2014, the PCB was changed to incorporate the 18k.
- By July 2013 I'm pretty sure the LM1458N was removed from production.
The LM1458N was only used units without the traditional purple color.
So apart from a fuzzy region around July 2013 the V2 schematic never had LM1458N's
I've put together a Timmy *V2* "This is your life" document.
(It's attached to the post but you have to be logged in to get it.)
It's the best I can do with the info I have.
I don't think I will add to it. I'm sure it has some errors.
Use the manticorefx effects site link for pics. However I'm pretty sure it doesn't cover all the cases.
The version number in the doc are mine. It's the only way I could keep track of them.
(https://i.postimg.cc/TLRnsPY6/Tim-the-Enchanter-Monty-Python-The-Holy-Grail.jpg) (https://postimg.cc/TLRnsPY6)
Lol. There are some who call me... Tim.
QuoteLol. There are some who call me... Tim.
Indeed.
"What manner of man are you, that can summon fire without flint or tinder?"
PaulC said that's where he got the name for the Tim pedal, which later evolved into the Timmy pedal.
QuoteThanks! I love these kind of work.
It takes a lot of time. I promised myself I'd stop doing that type of stuff :icon_rolleyes:
I'm comparing the veroboard layout in tagboard guitar fx web site
(http://3.bp.blogspot.com/-imI0JcQ_gSI/VAmT8yw-f3I/AAAAAAAAImM/MqxVruF6nCo/s1600/Paul%2BCochrane%2BTimmy%2BRev%2B2.png)
with the schematic you guys drawn because I want to update it.
First of all the easier mod to update.
- Replace the 1.5k with a 1k.
- Replace the two 3.3k resistors to the right side with two 10k
- Replace the 47nF cap with a 39nF
- Add the 2.2nF
We can do it, even if the position is a bit unhandy. This cap has to be in parallel with pin 6 and pin 7 of the IC.
We have to use two holes, one under the 1uF cap (the bigger, near the 47uF cap) on the same stripe of the pin 6, and the other hole is to the right of the 1uF between it and the 3.3k resisitor, on the same stripe of the pin 7.
Now a thing I need some help.
- Add C4, the 47pf cap in the new schematic.
I still didn't understand what happens in these cases. It's hard for me explain this and I tried to write it a lot of time, but to be brief... How much important has the position of the 47pF? Can I put it simply in parallel between the pin 3 (the signal) and the pin 4 (the ground) of the IC without take care if it's before or after the C3, R3 and R4?
Because there's a place, two holes, between the two wires Drive 3 and Input. Could it ok?
Then there's some difference in the power filter. The schematic has a protection diode (D1) on the ground, while the veroboard layout has the diode and a 100R resistor along the 9v. I think we have enough room to make some changes. Anyway, I don't know how much it could make some difference in the sound.
I have a doubt about the number of the clipping diodes. Why in the layout there are seven diodes and in the schematic there are five? Did I miss something?
QuoteFirst of all the easier mod to update.
... 1uF between it and the 3.3k resisitor, on the same stripe of the pin 7.
All that looks OK to me.
QuoteCan I put it simply in parallel between the pin 3 (the signal) and the pin 4 (the ground) of the IC without take care if it's before or after the C3, R3 and R4?
...
Could it ok?
Across pin 3 and pin 4 is correct. It matches the new schematic. (It also matches what I can see on the pics of the actual PCB.)
QuoteThen there's some difference in the power filter. The schematic has a protection diode (D1) on the ground, while the veroboard layout has the diode and a 100R resistor along the 9v. I think we have enough room to make some changes. Anyway, I don't know how much it could make some difference in the sound.
You did well to find those small details. The protection on that layout does not match Timmy V1.0 or Timmy V2.0. Both Timmy V1.0 and Timmy V2.0 do not use the 100R and the diode is not in series with the power. The actual circuit connects the diode in a completely different way. You need to connect it across pin 4 and pin 8, as shown in the new schematic.
As for the difference in sound it will be small. If you leave the layout as shown it will be like running the real Timmy circuit with a slightly flat battery. I am in two minds about updating the layout. I read that PaulC changed the 3.3k's to 10k's in order to gain a small amount of extra headroom from the opamp. With the layout as shown it is actually throwing away headroom because of the voltage drop of the diode and the 100R resistor. So if you just want something that sounds very close leave the layout as is. However if you want a true clone which goes along with PaulC's intentions then you should change it.
Quote
I have a doubt about the number of the clipping diodes. Why in the layout there are seven diodes and in the schematic there are five? Did I miss something?
The original Timmy 1.0 had six clipping diodes and a 2-way dip-switch. That Timmy V1.0 layout is missing the diodes and the dip switch. For Timmy V2.0 the circuit uses 5 diodes and a toggle switch. The toggle switch is mounted on the front of the enclosure. To make the layout a full Timmy V2.0 you will need to add the extra diode and also add some connections for the toggle switch. The added parts are D6 and S1 on the schematic.
Thanks to you for the help, Rob! ;)
I'd say, to adjust the power section as the original Timmy, we can remove the 100R, take off for an instant D8 polarity protection diode, move the 9v just under the Vol 3 wire. The D8 can goes in parallel with the 47uF cap between the 9v and the ground, following the schametic. Maybe we could handle a bit the surface spacing, but in the end it will be ok, I think.
About the clipping, in this page https://www.diystompboxes.com/smfforum/index.php?topic=108272.msg986355#msg986355 I found this:
(http://i80.photobucket.com/albums/j190/Leeroyfunk/Timmyclippers_zpse85358ed.png)
This explain me how the Timmy V1 with the internal switch worked: you can let disconnected the diodes, or you can add one diode (or the other one) or you can add both those two diodes. For a three way mode.
The external switch makes the same thing in a different way. You can exclude the extra diodes, or you can add one diode or you can add two diodes. And in this case we have one more diode, but the clipping modes are exactly the same.
But there's still something I can't get with the new connections of the diodes in the newer schematic.
I update the nocentelli sketch:
(https://i.imgur.com/RymwEPA.png)
No, I can't follow the signal through these connections and these diodes. ???
QuoteBut there's still something I can't get with the new connections of the diodes in the newer schematic.
The first schematic is close to Timmy V1 but it isn't 100% correct. The 4 diodes should have a connection between the top 2 diodes and the bottom 2 diodes. I remember reading that PaulC said "it makes a difference".
The second schematic is close to Timmy V2 but it isn't 100% correct. It creates a circuit which functions like Timmy V2 but does so by starting with Timmy V1 then changes the dip-sw to a toggle switch.
The third schematic is how the Timmy V2 is wired on the PCB. Timmy V2 only as 5 diodes so it cannot use the method of the second circuit which has 7 diodes. (Timmy V1 has 6 clipping diodes.)
IMHO, the second schematic and third schematic will sound virtually identical. For the 2 diode mode (compressed), the clipping action of the second circuit comes from the lower 2 diodes and the upper 4 diodes do not conduct. For the third circuit the clipping action comes from the right 2 diodes and the left 2 diodes are out of circuit.
[EDIT: Maybe one thing that might be confusing. When the two diodes are switch in on the second circuit they limit the voltage to +/-0.6V. This prevents the top four diodes from conducting. The four diodes don't conduct until the voltage reaches +/-1.2V but the two diodes stops it getting there. So it is like the four diodes are switched out.]
Thanks again, man!
The last thing you added was told to me some years ago by duck_arse. I never really really get it. Maybe this time I got it.
Anyway, while I was staring the third schematic it was like a little lamp that turned on in my mind, and I guess I finally got something! ;D But not completely.
I'm very sorry if I insist, but there's really something that confuse me in the cross of connection in the third schematic, and maybe in the notes on the schematic drawn early by you:
"Clipping Switch S1:
1-2: Asymmetrical 1|2 diodes
Off (center): Symmetrical 2|2 diodes
2-3: Symmetrical 1/1 diodes"
The thing I don't get is how exactly the signal pass through the all the diodes in this three modes.
When S1 connects 2 to 3 I get that D2 and D5 are bypassed because the switch has create a parallel connection. So we have D3 and D4 in parallel, D2, D5 and D6 are out, so just two diodes. I used to write this like so: 1||1, and maybe we are ok.
When S1 connects 2 to nothing we still have D6 out, but we have four diodes where series and parallel confuse me. That vertical link between the four diodes is driving me crazy. What is happening? We really have two pair of diodes in parallel? Like this 2||2?
When S1 connects 2 to 1, of course, happens the same thing when S1 connects 2 to nothing plus D6. But how we can get 1||2? I mean one less diode?
If there's somebody with a lot of patience that can help me, please.
Thanks to all!
Quote1|2
Don't get stuck on the "|" or "||" it's only a short hand of writing down the configuration in *"words"*. In the end the circuit diagram represents how it is connected.
QuoteD2, D5 and D6 are out, so just two diodes.
That's correct.
QuoteWhen S1 connects 2 to nothing we still have D6 out, but we have four diodes where series and parallel confuse me. That vertical link between the four diodes is driving me crazy. What is happening? We really have two pair of diodes in parallel? Like this 2||2?
When you have the extra link it's more like 1||1 in series with another 1||1. When you take the link out it's 2||2. The simple way to think about it is the diodes can only conduct in the positive direction so if current flows left to right D2 & D3 conduct and D4 & D5 are off. When current flows from right to left D4 & D5 conduct and D2 & D3 are off. If you think this way you should see that the circuits do the same thing with the link in or the link out. You might ask what's the difference, why bother? PaulC said it makes a difference to him. If the diodes are all the same I'm not sure I can explain *why*.
QuoteWhen S1 connects 2 to 1, of course, happens the same thing when S1 connects 2 to nothing plus D6. But how we can get 1||2? I mean one less diode?
If you understand the note at the end of my last post about 0.6V and 1.2V you should get this. So in one direction you have D4 and D5 clipping just like the case with four diodes. However when the current is reversed. D6 which is 0.6V is connected in parallel with D2 + D3 which is 1.2V so D6 makes D2+D3 look like they are out of circuit. So it's like 4 diode case in one direction and the 2 diode case in the other direction.
Rob beat me to it, but reading another explanation might help.
Quote from: Elijah-Baley on December 15, 2018, 05:11:46 PM
When S1 connects 2 to nothing we still have D6 out, but we have four diodes where series and parallel confuse me. That vertical link between the four diodes is driving me crazy. What is happening? We really have two pair of diodes in parallel? Like this 2||2?
Current can only flow in a diode's forward direction (assuming the voltage is lower than the diode's reverse breakdown voltage). Trace current flow and see how many paths you can make through diodes between pins 1 and 2 (paths that end up back where they started don't count). There are only two paths - one in either direction. From pin 1 through D4 and D5 to pin 2, and from pin 2 through D2 and D3 to pin1. The center connection of all four diodes is distracting but it actually does nothing, other than enable the clever clipping switch arrangement.
Quote from: Elijah-Baley on December 15, 2018, 05:11:46 PM
When S1 connects 2 to 1, of course, happens the same thing when S1 connects 2 to nothing plus D6. But how we can get 1||2? I mean one less diode?
It is not "nothing plus D6." D6 is in parallel with the D2-D3 series, but because a single diode has half the forward voltage of two diodes, current flows through D6 only. (I think this is a simplification - it may actually be more complicated but the net result for soft clipping is the equivalent of one diode in operation.) The D4-D5 series still operates in the other direction.
Great! It's more clear, now! ;)
So, with the corrections of the Timmy's schematic I'm wondering what about the Jan Ray, too. Everybody consider it how a clone of the Timmy with some mods. And the clipping section? The Jan Ray has the four diodes, but without that link. Who knows if it is really like that or this mistake of the missing link has been transferred to it.
QuoteSo, with the corrections of the Timmy's schematic I'm wondering what about the Jan Ray, too.
Before I started this thread I had many circuits and layouts of "Timmy". All different! I had no idea what was real, what was bad tracings, what was a DIY version. A big mess! It's a relatively simple circuit so how can things get so out of hand! It happens *all the time* many simple circuits suffer the same problem.
The main problem is people put up schematics that they know aren't 100% but they make it out like it *is* the real thing. Once that happens the error propagates all over the place. When I don't know something I try to write it on the schematic. At least then someone only has to check *that* small part. Some people don't have the skill to trace the whole circuit but if they only have to check a small section they can usually do it.
Wrong pot tapers, or no pot tapers happens is another one. If DIYers don't like the pot taper they change it on the schematic to what they have used but they don't add any notes.
Just look at the Klon. There were *many* different schematics on the Web and one guy set out to finally get it right. It took a couple of attempts (which is normal) but he finally got there.
QuoteEverybody consider it how a clone of the Timmy with some mods. And the clipping section? The Jan Ray has the four diodes, but without that link. Who knows if it is really like that or this mistake of the missing link has been transferred to it.
If you look at the Jan Ray it has many circuit differences, yep, including the diodes. So it's not really a Timmy.
When I researched the Timmy I found a post from PaulC saying if you are going to put up a schematic of Timmy, call it Timmy! don't call it something else. He even corrected people's incorrect schematics and helped with missing values. I remember him saying that the 4 diodes have the connection between them!!! and "it makes a difference".
FYI, IMHO even Timmy V1 circuit isn't quite correct:
- IC's have wrong (or no) pin numbers
- Bass and treble pots don't connect pin 3
- Pretty sure the dip-sw connects to the opamp output, not the opamp input.
- When you look at the Timmy V1 PCB or Vero layouts there's a 3k3 resistor missing.
I think the 3k3 is wired to the back of the Gain pot.
- There's not enough wires to connect all the pots so I think at the opamp output
there's only one wire and the Gain and Treble pots are connected with together off the PCB
then one wire runs back to the PCB.
So many details that are possibly wrong and the circuit only has one IC!
EDIT: Never mind - momentary lapse of sanity. :icon_eek:
Hi, guys!
I'm still working with the new layout of Timmy. I was a bit busy. There just a thing I have to say.
Looking at the layout, posted above: https://www.diystompboxes.com/smfforum/index.php?topic=121481.msg1142928#msg1142928 I noticed that the diodes, after all we talked about the connections, etc., they are connected in the correct way, like the last update schematic. If it is so I will not move anything, except the clipping switch that we need to update, and it is a bit hard to got it clean as possible. Probably we should have a flying diode, we'll see.
I'm still waiting for the final layout 8)
You're right. I made and forgot it! ::)
Anyway, I just modified the old layout you can find on tagboard web site. Tha main difference are in some value.
Input cap: from 47nF to 39nF
Resistor cap: from 1.5k to 1k
Feedback resistors in the second stage: the two 3.3k are now 10k
Add a 47p from input to ground, you can find a place on the left of the board
Volume pot: from 10k log to a 25k log with a 18k between lug 2 and 3.
And the some minor changing in the power supply. The new schematic shows not a diode in line to the 9v, but one across the ground. A 1N4001 will be fine.
Now, looking my layout again, I'm not sure is really ok, I just some doubt about the clipping mode. I remember I had some doubt in the past. I'll look at it, again.
Thank you!
I think I'll try to build the "new" Timmy and these values.
Yes, you had some doubts about clipping - if you find out something, please drop some info :)
cheers!
Quote from: Elijah-Baley on December 19, 2018, 12:57:06 PM
....... Probably we should have a flying diode, we'll see.
all flights cancelled, all diodes grounded.