New circuit, anyone feel like breadboarding today?

[JimRayden]

I was playing around with the fetzer valve and two germanium diodes today, and came up with this lil' beast. It sounded real sweet to my ears, so I put it on the paper.

I need someone to test it out with other gear and compare it to other stompboxes, as I don't have too many. I compared it to my TS7 and liked mine more because of increased presence. That's propably just more highs and lows on my circuit. Despite that, mine sounds quite middy and was real responsive to my playing. I need someone to "clean up" my schemo, remove the unnecessary parts (as I've built it by ear) and compare it to other stompboxes out there. (A low-pass tone control in the end would be a great idea, it needs some taming in the high freq. area)

http://ftp.taaviaudio.com/homes/JimRayden/distschem.jpg

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Jimbo

[aron]

It looks like it would sound and feel good. It would have a squishy tone due to the diodes being between the two stages. A simple cap to ground might be all it needs at the end to smooth it out a little.

[JimRayden]

It looks like it would sound and feel good. It would have a squishy tone due to the diodes being between the two stages. A simple cap to ground might be all it needs at the end to smooth it out a little.

Thanks, Aron. Breadboards ROCK! Mmkay, anyone have a few spare minutes to breadboard this thing and give it a face-to-face meeting with other stompboxes?

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Jimbo

[vanhansen]

Looks interesting.  I may have to try it out.  I need to make some room on my breadboard though.  It's got 3 projects on it right now. 

[JimRayden]

That's more like it. Come on people, help fellow forumer out. 

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Jimbo

[Transmogrifox]

It definitely looks promising.  I don't think I'll get around to breadboarding it until Thursday, but I do have a batch of 2N5458 FETs that are getting anxious for their first circuit.  It shouldn't take me more than 10 min. to breadboard. If I really like it, I'll post clips.

[MartyMart]

Jim, I'll put one together today ! looks good to me, I may use 10k trimmers for the Drains
just to get 4.5v bang on, rather than the 8k2/9k  approximations
A 1n to 3n3 cap after the diodes will probably pull down some high "hash"
It could use an input cap, which I put on my Fetzer, otherwise I was getting
some "hash/shit" when adjusting the gtr vol pot.
A 22n to 47n should do it.

Marty.

[lovekraft0]

Is this right?


I had trouble reading your schemo - old eyes, I guess.

[MartyMart]

Is this right?


I had trouble reading your schemo - old eyes, I guess.

That's how I read it ( 42 year old eyes )
My changes are :
1M at input and a 47n cap before 33k to Q1 (ROG higher gain mod )
5n coupling cap to a 22n
1k5 off Q1 could be a 2k - 5k pot for a gain control, with the 4u7 off
wiper to ground.
Nearly done, just pot/jacks to go !!

Marty.

[MartyMart]

Done and sounding quite sweet !
Not getting much "crunch" unless I boost before it or use a humbucker
gtr.
I reduced the 22n coupling cap to 6n8 as that was too "thick" sounding
kept the cap and swopped resistors at the front and a 1n to ground
before the output pot.
I think its worth having a gain pot off Q1, for a clean/drive option and
some control.
I have a small problem around Q1 causing level drops occasionaly, so
I'll re-wire that section, probably because I used a piece of scrap
stripboard and its all a little "cramped" !!
Marty.

[JimRayden]

As to the high gain mod with 1M/33k instead of the 68k/1M, I tried it before making the schemo, I didn't like it too much.

I was also considering an input cap but I started to rush drawing it and uploading.

I agree everyone there should be a gain control but I hate pots in my breadboards, they barely fit and are a hassle to set up. There will be a gain pot as you described, Marty, and there would also be a switch between the diodes and signal line. When the switch is on, it connects the diodes to ground and selects the "diode drive" mode. When the switch is off, it disconnects the diodes and as the signal will get stronger, also starts driving the second transistor harder. That'll be a kind of a "transistor drive" mode. I gotta try it out when I get home.

I reduced the 22n coupling cap to 6n8 as that was too "thick" sounding

If you mean the cap between the stages, it actually was 5uF before, you must've misread it.

EDIT: Oh, and yes, your schemo is correct, Marty. If you find time, introduce some of your other pedals to my lil' friend. Give it a rough test ride, I want to make it a good as possible. I'm gonna get to drive it on full volume tomorrow, so I can compare it to my Tubescreamer and even to the tube preamp of my own design.

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Jimbo

[MartyMart]

If you mean the cap between the stages, it actually was 5uF before, you must've misread it.

EDIT: Oh, and yes, your schemo is correct, Marty. If you find time, introduce some of your other pedals to my lil' friend. Give it a rough test ride, I want to make it a good as possible. I'm gonna get to drive it on full volume tomorrow, so I can compare it to my Tubescreamer and even to the tube preamp of my own design.
Jimbo

Sorry Jim I've confused things, I saw that it was a 5n cap, tried a 22n and found it sounded too thick !
Went down to a 6n8 and I'm happy with that value
It sounds great driven with a "Sparkle boost" but I could use some more "grit" from it.
The gain pot will do it !
EDIT:
Problem fixed, I had the two trim pots wired together at the drains, screwing the voltage some !!

Marty.

[JimRayden]

Sorry for the typo too, I ment 5nF.

I just got home and the more I play it, the more I like it. when I A/B it with my Tubescreamer... I don't know if my TS is f**ked up but it sounds like a clean guitar sound with some fizz in the background and with alot of sustain. In conclusion, I love the ound of mine and I'm getting rid of the TS. Now I'll go and test it with Marty's suggestions (input cap, smoothing cap) to find out if it could sound any sweeter.

Damn I can't get rid of the feeling that there is that wierd overtone going on... maybe it's a mid hump or something... I don't know but it sure sounds good.

PS: Maybe it's just the honeymoon period and I should wait a few weeks and do another review on the circuit.

EDIT: Just tried the mods. I didn't hear any difference with the input cap, so I just left it there. I also tried the smoothing cap next to the diodes but I like it better without.

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Jimbo

[vanhansen]

PS: Maybe it's just the honeymoon period and I should wait a few weeks and do another review on the circuit.

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Jimbo

I know what you mean.  I've been on the honeymoon with my Marsha Valve (v1.1) and still am on the honeymoon.  It just works incredibly well with my Marshall.

[JimRayden]

Hmm, it needs more sustain on the highs... I think I'll try another stage in the front of the circuit boosting highs, then mess with the caps to dial in the same tone.

EDIT: Tried the stage in front but it just ruins it. Actually I'm happy with the highs as they are. I like dynamic playing anyway. And I can't put the guitar down. I'll make sure to record some tomorrow.

EDIT2: Oh, and sorry for comparing it to the TS. It's a pedal with a whole different character but I have nothing else to compare it to. I just found out that I'm not a TS-type player afterall.

EDIT3: Added a one knob low pass tone control. On its brightest setting, it still sucks the cool overtone outta the circuit. I think I'm gonna have to go with a switch between dark and bright mode.

Good night.

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Jimbo

[MartyMart]

Jim, that's funny, what you said about the "TS" circuit, the DIY version that I build sounds great
with both my amps and my little SS practise amp, but my "real" TS-9, which is modded back
to 808 & tone caps/etc sounds very "wierd" !
I dont know that there's a problem with it, but somehow those valve amps dont respond to
it too well.
It sounds "choked" and a bit "woolie"  !
Perhaps I should give it a check over, could be that the buffer isnt working right, and it seems
to have less "gain" than I remember ....
Sounds like it needs thinning out a bit too.
Marty.

[JimRayden]

Jim, that's funny, what you said about the "TS" circuit, the DIY version that I build sounds great
with both my amps and my little SS practise amp, but my "real" TS-9, which is modded back
to 808 & tone caps/etc sounds very "wierd" !
I dont know that there's a problem with it, but somehow those valve amps dont respond to
it too well.
It sounds "choked" and a bit "woolie"  !
Perhaps I should give it a check over, could be that the buffer isnt working right, and it seems
to have less "gain" than I remember ....
Sounds like it needs thinning out a bit too.
Marty.

Actually my TS is the TS7, the one with a crappy footswitch and a gain boost switch. I wasn't saying there would be anything wrong with it, I just like my new circuit more.

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Jimbo

[Transmogrifox]

I gave it a try.  It's hard to know how it compares to yours since I had to make some pretty singificant changes to properly bias 2N5457's. 

I ended up with a 4k7 in the source of the first stage with about 7.3k in the drain--used the same 4.7u bypass cap in the source.

The second stage had around 2.5k in the source, and a 10k parallel something I picked up off the floor.  It has a nice high end response.

Anyway, I got the thing working and biased correctly.  It sounded very nice.  It had a good dynamic feel...of course, I was unable to determine how much of that was my amp and how much was the circuit.  It made a great booster on the amp either way and I was milking out some very good sounds that I could feel through the strings.  That's what I liked.  My guitar didn't feel like what an electric guitar feels like when you just pick it up not plugged into anything.  It felt like the sound coming out of it my amp.  How else do you describe it?  You guys know what I'm talking about or you wouldn't be building stompboxes.  Commercial pedals would do all you needed.

Nice work, Jim Rayden.  I can see why it keeps you playing for hours.

[JimRayden]

Yea, actually I noticed I suddenly have a new amp too.

Oh, and are you guys sure you're using Ge diodes? I guess that's where the magic comes from.

Hmm, to think of it... do we really need the second transistor stage? I mean, do the diodes attentuate it enough to keep the second stage from overdriving or is the sound like a mesh between diode and transistor OD? I'm guessing the second one.

In a few hours I'll be witnessing the circuit in its full beauty... at band rehearsal. I'm hoping to get some recorded too.

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Jimbo

[JimRayden]

Okay, that was great! My amp is a VERY crappy old 1x12" Vermona, the cleans are horrible, poingy and such, not to talk about the buzzy fuzz channel. The minute I switched my baby on and turned that thing up loud... guess who's got a $2 Marshall!!! Although, I must give some credit to the Greenback I have in there (Oh yes, and the honeymoon period). I'll try to box it up tomorrow and go to a friends house to try it with other guitars and amps.

I also have some sound clips on tape, I need to figure out a way to get them into computer. I seem to have lost a cable connecting my computer and stereo.

I'm also expecting more people to breadboard it, comment on it and also suggest improvements on the circuit.

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Jimbo