Rookie question: Re-voicing Fuchs ODS

[Strumbringer]

Hi Guys, first post and just joined the forum after reading/lurking for sometime. I'm definitely in the rookie category, when it comes to amp building and amp tech work, having only built one 18 watt 1974x amp from a kit.

My question is this: I have a Fuchs ODS Classic and after borrowing a few D-style clones from a friend to test drive (Bludotone, Amplified Nation, and Louis), I noted they all had a great midrange honk with the mid boost engaged, which isn't present in my Fuchs when its mid boost is on. I was thinking that changing cap values in the mid boost (there are two in the Fuchs: C5 and C8, which I believe are .001 and. 002 uf. There's a push/pull to select which cap you'd like when the mid boost is engaged).

The Bludotone Ojai (102 clone, I believe) sounded dead-on to what I'd be looking for, with the mid boost engaged. It had that honk and vocal vowel thing.

Is it a fools errand to believe that I could swap some caps and get in the ballpark of the Ojai? I'm sure there's more to it than just cap values, but what do I know. That's why I'm hoping to ask you all.

[martin manning]

Maybe Andy will have some recommendations ;^)

[Strumbringer]

Maybe Andy will have some recommendations ;^)

Yeah, both Andy and Rich are pretty helpful. That’s how I know the locations and values of the mid boost two caps. I’d be really interested to know if it’s even possible to move my amp in the direction of sounding like the Ojai/102.

[Stevem]

And you played all these amps thru the same speaker(s)?

[Strumbringer]

And you played all these amps thru the same speaker(s)?

Indeed I did. I had all at my house for about a week, two Bludotones (Ojai and 80s Classic), Amplified Nation ODR, Louis Cobra, and my Fuchs ODS. All played through my 2x12. I did a lot of A/B and recorded clips for my analysis.

[WhopperPlate]

And you played all these amps thru the same speaker(s)?

Indeed I did. I had all at my house for about a week, two Bludotones (Ojai and 80s Classic), Amplified Nation ODR, Louis Cobra, and my Fuchs ODS. All played through my 2x12. I did a lot of A/B and recorded clips for my analysis.

all of those circuits essentially significantly different from each other, at least more so than just a different mid boost cap value.

Beyond that , if they are all doing the dumble mid boost thing than I don’t think any of those amps have a different value there , besides the Fuchs with the optional .001uf. .002uf is generally standard fare.

I would investigate the differences between the rest of the circuits. Now that I recollect , the Cobra is basically 183, which is pretty different than the rest of those amplifiers afaik.

Either way , I bet money the difference isn’t the mud boost cap value . Comparing 5 amps, by 4 different builders, and determining what makes each tick isn’t exactly a simple or easy endeavor, even if they are DLL dumble inspired .

[Strumbringer]

And you played all these amps thru the same speaker(s)?

Indeed I did. I had all at my house for about a week, two Bludotones (Ojai and 80s Classic), Amplified Nation ODR, Louis Cobra, and my Fuchs ODS. All played through my 2x12. I did a lot of A/B and recorded clips for my analysis.

all of those circuits essentially significantly different from each other, at least more so than just a different mid boost cap value.

Beyond that , if they are all doing the dumble mid boost thing than I don’t think any of those amps have a different value there , besides the Fuchs with the optional .001uf. .002uf is generally standard fare.

I would investigate the differences between the rest of the circuits. Now that I recollect , the Cobra is basically 183, which is pretty different than the rest of those amplifiers afaik.

Either way , I bet money the difference isn’t the mud boost cap value . Comparing 5 amps, by 4 different builders, and determining what makes each tick isn’t exactly a simple or easy endeavor, even if they are DLL dumble inspired .

You know, these are all really good points. I can say with certainty that the Louis was the most different of the rest and probably not the sound I would be going for. The Amp Nation ODR was a low plate circuit and the Bludo’s were high plate skyline. So I guess I would need to conclude that there are so many nuances between those amps and my Fuchs, so perhaps trying to mod my amp is indeed a fools errand, because there are too many differences.

[Reeltarded]

Wrong conclusion.

[WhopperPlate]

Wrong conclusion.

I agree

Which one of those amps specifically did you like the best ? Narrow in on that one …

[GAStan]

IMHO you're putting too many variables into the equation. I'd suggest only looking at the differences between your amp and the amp you want it to sound like. Do the other two really matter?

Edit: looks like Charlie beat me to it...

[Strumbringer]

Wrong conclusion.

I now realize I'm messaging to a group that likely always have their soldering irons hot and ready to go.

Well, I'm all about a solution, so if I can learn about some component enhancements, that would be great. I learned that Fuchs does not provide schematics, so I really wouldn't know where to start. I do know that of the amps I played, the Ojai was King. If I can get into the ballpark of that honk tone, I'd be one happy camper.

[Reeltarded]

Hot and ready is a registered trademark of Little Cease and Desister's.

I think you can look at a similar schematic and understand the basics in an hour or two and compare your circuit to the known one you like most.

You said honk. Two questions I have when playing one of these amps is (1) eq control range feels great (2) value of OD control pots.

[WhopperPlate]

Like you said Ojai is apparently 102 ; high plate with skyline tonestack , Overdrive entrance 220k>100k trim >68k >v2 .

Is your Fuchs a low plate or high plate? Considering the few differences between 124 and 102 it wouldn’t be too hard to modify one into the other , and I assume the Fuchs is some similar derivative.

[Strumbringer]

Hot and ready is a registered trademark of Little Cease and Desister's.

I think you can look at a similar schematic and understand the basics in an hour or two and compare your circuit to the known one you like most.

You said honk. Two questions I have when playing one of these amps is (1) eq control range feels great (2) value of OD control pots.

Yes, I should find the #102 schematic and start to study it. I wish I had a Fuchs schematic, but oh well.

The EQ range: Generally very good on the Fuchs ODS. I note that when on the EQ2/Jazz setting, the midrange control has much less effect on the tone. The value of the OD control pots- Unsure.

[Strumbringer]

Like you said Ojai is apparently 102 ; high plate with skyline tonestack , Overdrive entrance 220k>100k trim >68k >v2 .

Is your Fuchs a low plate or high plate? Considering the few differences between 124 and 102 it wouldn’t be too hard to modify one into the other , and I assume the Fuchs is some similar derivative.

I believe it's high plate.