A TS with bandaxall tonestack, a germanium transistor wired as a clipping diode and a high fidelity op amp. Schematic is avaiable HERE.
A TS with bandaxall tonestack, a germanium transistor wired as a clipping diode and a high fidelity op amp. Schematic is avaiable HERE.
Thank you!
ReplyDeleteYep, really looking forward to giving this one a try!
ReplyDeleteHa! Just saw this come up on FSB the other day so ordered parts to give it a crack!
ReplyDeletehttps://www.freestompboxes.org/viewtopic.php?f=7&t=31031&p=283700&hilit=sidecar#p283700
There's a couple of differences between the schematics not sure if this was an earlier version, but you can verify the parts in the gutshots.
2x 120UF instead of 220UF
BC549C instead of BC549
B5K instead of B25K (Treble pot)
I’ve ordered an OPA2134 which is mentioned to be a good sub for the LM4562.
Thanks for the headsup!
DeleteFound another schematic that matches your findings with 5kB Treble pot and 120uF power filter caps.
https://forum.pedalpcb.com/threads/hudson-sidecar.4920/#post-40856
Layout is updated.
My friend just brought some pedals to me to check out and the Sidecar is one of them. Lemme know if you need any close-ups.
Deletehttps://i.imgur.com/J4Xxy1A.jpg
https://i.imgur.com/siPaaxY.jpg
https://i.imgur.com/ojIXc15.jpg
Thanks, man. It confirms the schematic as far as I can see.
DeleteSo whats the other pedals?. Something that needs to be traced?
Interesting pics there. Where’s the germanium component? Just looks like two silicon diodes and an LED. I used to have one of the early vero versions and it was a Ge diode, SI and LED. At the time I thought there was a big transistor in there, but having learnt a bit since then I know it was actually a metal can opamp (LME 49720HA).
Deletehttps://i.imgur.com/B7LbBJe.jpg
Yeah, I don't see one anywhere. There's only 1 transistor on this board. Here's a couple close-ups for the diodes. Looks like the board is labeled 270, which would be the 1N270 so that makes sense for the "Germanium Clipping" but these meter out at .585 and .580 which is too high.
Deletehttps://i.imgur.com/ZkzkNeB.jpg
https://i.imgur.com/BYXocQc.jpg
Here's the IC, it's an LME49720 like yours, just not the metal can version.
https://i.imgur.com/Db7c6Bn.jpg
@fuzzhead
DeleteThe other pedals are an OCD V1.7, Hardwire Digitech Supernatural Reverb, and a Plasma Pedal. Man, that Plasma pedal is so cool.
What do these capacitors do in the circuit?
ReplyDelete120µF is quite unusual, would 100µF or 220µF make a big change?
These caps is for power filter and voltage reference filter. Both 100uf and 220uF will work just fine.
DeleteThank you for such a confirmation (and for the layout!)
DeleteThis might be a daft question, but why would a 120 be chosen over the other two? What benefit is there either way? Just curious.
DeleteCheers
Ben
No idea...there is no real benefit.
DeleteMaybe the builder have a large stock of these caps?
If you really want 120uFs there but don't have any on hand, you can use 100uFs with paralled 22uFs.
& he has a lot of 22n,330n,33n to use it in pairs =)
DeleteTag it!! Works great!
ReplyDeleteThanks Ben! I'll tag it.
DeleteThats cool, I helped with the layout of that original you linked too. I took a million pictures of my original and had someone else do the layout. Yours is much nicer and compact.
ReplyDeletesounds pretty interesting due to the baxandall EQ.
ReplyDeleteHad it on the breadboard and swapped the germ diode for fun. A silicon Tesla KF517A (around 40 hFe) sounded exactly the same to my ear as e.g. AC125 or MP21w (also around 40 hFe).
Anyways - cool pedal, great job :-)
forgot to mention that i swapped ICs too
Deletesettled with a Tl072 but i am sure u can use any dual opamp
there has to be some mojo flavour in drive pedals nowadays i guess :-P
I stacked two tl072s and used tje E B junction of a germanium transistor with hfe of 43. Also used a 2n3904 and 220uf in place of the 120uf.
ReplyDeleteBuilt this tonight. Sounds good so far. Only subs were 220uf in place on 120uf and a OPA2134 for the IC. Used a germanium transistor with around 60 hfe for Q2. Tried out different diodes for D1. D9E sounds pretty good but the volume drop is too dramatic. 2N2222A low 200s hfe sound pretty good for Q1 as well.
ReplyDeleteForgot to mention another substitute I found helpful. I did not have a 1mA pot, so I tried a 1mB. Hit max too early. Tried a 100kA and 250kA. Found the 250kA pot to work well.
DeleteIs it not the tone stack out of a Neve Sidecar console? Hence the name? Is the baxandall the same as the neve?
ReplyDeleteI've seen a few gut shots with what were obviously Ge diodes. This one looked like a transistor but may also have been a diode. The modern one uses Schottkey "equivalents" to 1n270 (so there isn't really an atom of germanium in the things). I think with so many variations, the bottom line is you can probably use whatever you want, and there isn't a single, canonical magic diode the way there is with a Klon.
ReplyDeleteI've made it! I Used LF 383. TL 072 working too. 4558 doesnot working, because there is need bias from 1/2 to 3 leg of chip.470-560kom.
ReplyDeleteI used in clipping Ge diode+si +led, & i made mode instead led i used 2n7000 +ge diod(like OCD clipping). So what i have to say, this pedal VERY similar to my Buffalo Fx TD-X! Like two twins! Anyway, I like it!
https://effectslayouts.blogspot.com/search?q=buffalo
DeleteI finished building it today, using 2N404 and LM4562 : it works very well, and sounds great!
ReplyDeleteHello - for some reason I simply can’t get this circuit to work. When turned on, I can hear it very very faintly wanting to work.. but that’s it.. knobs work as far as I can tell.. I’ve triple checked everything and can’t find any issue. When I press my finger beneath q1, the diodes and 33n caps the sound reappears closer to how it ought to sound. Then goes away when I remove my finger.. the harder I press the more volume/signal there is.. I’ve resoldered without success..
ReplyDeleteI’ve made some substations that have been ‘ok’d’ in the thread:
- didn’t have 120uf so just used 100uf.
- didn’t have the listed IC so used tl072
The above shouldn’t be an issue according to the build thread. However, I did notice most others substituted the 120u for 220u.
Here are some readings:
Q1 bc549c
E: 3.5
B: 3.9
C: 8.9
Q2 Ge trans
C: 4.48
B: 4.48
E: 4.48
Tl072
1: 4.49
2: 4.49
3: 4.49
4: 0
5: 4.49
6: 4.49
7: 4.49
8: 8.95
Most voltages looks good. I guess it is time to dig out the audio probe to locate where the signal stops.
DeleteOk, please don't get insulted, but did you run your jumpers along the metal trace side? Because it crossed my mind that it looks like every row touching one of the jumpers is showing the same voltage.
DeleteProbed around a bit last night.. noticed that the 10k resistor beside the 510k resistor and the 10k resistor below 150n aren’t producing any sound at all from either prong. .. ideas?
ReplyDeleteThe 510k/10k/10k resistors is part of the voltage reference network. Not a part of the audio signal, really.
DeleteDo you get any signal from the emitter of Q1? Pin 3 of the op amp?
This comment has been removed by the author.
DeleteHey.. thanks for your feedback! I’ve just gone over the whole layout (except for the diodes and electrolytic caps) and put a tick (signal) or x (no signal) on the image attacked to the link below. I could actually access the two 330n caps as well as the 150n cap.
ReplyDeletehttps://imgur.com/a/atNf84E
Audio probe results on the schematic:
ReplyDeletehttps://imgur.com/a/JSdK52q
Hmmm. your signal probe results looks very odd. You got signal at both inputs of the op amp and none at the both outputs. You must have a solder bridge or misplaced component since the signal seems to jump from from pin 2 to pin 5. looks like it is bypassing the clipping stage and possibly the the tonestack.
DeleteAnd no signal at pin 7 which connects to the output cap...
As I said, you must a have a short somewhere. Start checking for bridges and check your cuts. Start at pin 1 ,2, 6 and 7.
Again, thanks heaps for your input. I’ve gone over the whole board a cleaned up every row .. no dice.. I think I’m just about to pack it in and perhaps start over w another layout over at FSB .. I can’t imagine finding the solution here! Haha
DeleteI don't understand the germanium transistors layout... Should it be the other way around?
ReplyDeleteI thought B and E made it a diode... In this layout it's using C and B, E is going to nothing.
Collector and Base make a diode, and Base and Emitter make a diode, it just goes a different direction depending on PNP vs NPN. Personally, I get really annoyed when people bill a pedal that uses Germanium diodes as 'germanium' just because that is a popular buzzword. Germanium transistors functioning as transistors are one of the few 'mojo' classic components that truly does sound different (although even then, a well chosen cap between base and collector can make a silicon transistor very closely approximate germanium). A germanium diode isn't all that special, and if you find a silicon diode with a similar forward voltage, it will sound the same.
ReplyDeleteAhh wicked. I had wondered tbh if putting a 1N60P schottky in its place would give a similar result anyway, or even a D9B as I have a few, save using up my last OC71.
DeleteAs long as you have the polarity correct, it will work. The forward voltage will change the level of distortion, so different diodes will produce more or less. And the higher the distortion, the lower the volume. Unlike a transistor or tube that boosts the signal until it crashes into the power rails, a diode actually shaves off the signal to approximate the overdriven sound.
DeleteThis comment has been removed by the author.
DeleteR i know that, was just saying it may not be make much difference using the readily available pennies part in lieu of the new old stock.
ReplyDeleteI'll likely build it and send it to breadboard to test a few different choices for the Ge diode (probably try against a second LED, a
1n60p and a D9B and pick my fav) . I do have a question you could probably answer...
Think I'm going to add a charge pump like a broadcast then it can have a voltage switch. The sidecar does support 24v with a min of 50mA so a Lt1054 pump should do the trick. However, LM4562s not easy to get here at the moment (just ebay pickings which I wouldn't trust). Was going to use either a TL072 or OPA2134 but I think they can only do up to 18V?
Well.... I built it. All working. Found a LM4562 in the end, built to spec above inc 220u capacitors.
ReplyDeleteI also added the charge pump section from the broadcast on a seperate board so it swap between 9/24v, and two switches to swap out tge germanium for another LED and lower value cap instead of the 470n (tames low end into the diodes case it's being to bassy).
Pics and gut shots below
https://www.facebook.com/1825353937693346/posts/3193254687569924/
This comment has been removed by the author.
ReplyDeleteI finished this! is my third build, it works but it sound like and old fuzz with a lot of distortion and a weird fizzy tail like a second parallel distortion, all controls are working.
ReplyDeleteI used:
BC549C (320hfe)
MP16B (90hfe)
TL072
1N4148
1N5817
3m red led
(All with sockets)
Any suggestions? I'm a newbie on this but I know that fixing this kind a problems is a good way to learn. Thanks in advance.
This comment has been removed by the author.
DeleteThis comment has been removed by the author.
ReplyDeleteThis comment has been removed by the author.
Delete