Fuchs ODS too spiky on the treble side

[alvarezh]

It's certainly the first time I read of such an issue about a Fuchs on this forum in the five years I have been here.

It would be nice to know if this is a recent problem, or if it came from Fuchs that way. Maybe the amp was touched up by someone if it was not bought new, or a part value (or factory miss labeled part) was miss installed somewhere. Mistakes do happen although I tend to think Andy has a good QC system in place to catch such anomalies (again, assuming no one has tampered with it after after leaving N.J.).

But like a good doctor, asking the right questions (obviously, to the owner in this case) sometimes leads to the right causes.

All the best.

[FUCHSAUDIO]

It's rare in my experience, although I only have a few thousand amps out there...so time will tell if the voicing is successful.

Raising the cathode cap values certainly can help in the case of someone using only (or mostly) Strats, particularly those with low output single coils. The switch being referred to has two functions. It's a 4-position dip switch, and one position adds a "Fet load" resistor on the last B+ tail, which allows tailoring the B+ depending on the 12AX7 types in use. a JJ (for example) rarely needs the tail to get the 175/190 range I like. Sovtek or Tung-Sols or EH's seem to need a load there, or they run higher b+ as they draw less current. The clean-II coupling cap can be raised from the .02 currently to .047 or more, if you like. Early units were .01 btw.

Obviously, tube brands can affect this as well.

The remaining switches add various bypass caps to the first input tube, to tailor the low end response, depending on the model. Low power amps like a 30 get a little less low end than a 100 would. The 1-UF is one of a number of values available, since you can switch in more than one cap at a time.

An .01 mid cap is also a good change to the tone stack for Strat users, as we all know.

The reverb circuit itself is not adding any treble. Depending on the age of the amp and the type/brand of pan, there might be a tweak to the reverb return amp to reduce some of the highs in return circuit. Some of the newer Accutronics Korean pans are somewhat brighter than the older US made pans, and can benefit from that tweak. The circuit is designed to be 100% out of circuit when not in use, and any brightness would be from the reverb return itself being bright, which is easily trimmed down. Just raise C-17 (near single point board ground at reverb circuit) from .002 (to .0047 or .0068).

There is a mild HF lift (above 6 or 8 K) in the loop, which a 220 pf plate to cathode on the loop return tube could trim a little bit.

"Fuchs may be brilliant,but I can't stand that amp". Nice. And people ask why more builders dont come here much....

[vibratoking]

"Fuchs may be brilliant,but I can't stand that amp". Nice. And people ask why more builders dont come here much....

Andy...your detailed answer is appreciated. I continue to learn from your posts so please keep them coming. I am glad that you took the high road on this one.

Keep in mind that the quote above is from ONE member that made inappropriate remarks about something that he obviously does not understand. Several of us tried to inform the OP that your amps don't typically sound as he described.

[FUCHSAUDIO]

Thanks Vibratoking. There's apparently a finer line between humor, sarcasim, and professionalism than I thought.

[FUCHSAUDIO]

It's certainly the first time I read of such an issue about a Fuchs on this forum in the five years I have been here.

It would be nice to know if this is a recent problem, or if it came from Fuchs that way. Maybe the amp was touched up by someone if it was not bought new, or a part value (or factory miss labeled part) was miss installed somewhere. Mistakes do happen although I tend to think Andy has a good QC system in place to catch such anomalies (again, assuming no one has tampered with it after after leaving N.J.).

But like a good doctor, asking the right questions (obviously, to the owner in this case) sometimes leads to the right causes.

All the best.

Appreciated sir. Since we have been selling amps since 1999, the incidence of people tweaking mods and production amps inevitably will increase.

[bluesfendermanblues]

It's rare in my experience, although I only have a few thousand amps out there...so time will tell if the voicing is successful.

Good one Andy

You thorough reply is the gesture of a true gentleman!

[LeftyStrat]

"Fuchs may be brilliant,but I can't stand that amp". Nice. And people ask why more builders dont come here much....

Andy, your contributions are always appreciated here. Don't let the comment of one poster taint your opinion of the rest of us.

[FUCHSAUDIO]

Although it appears to be down at present, the OP did at one point have a website where he sold his own D-clones. Not sure if he still does, but it should be noted that he was (or is) a "manufacturer" of amps.

[mobisimo]

I love my Fuchs Bassman ODS100!

Edit: Andy also promptly responded to a question I had asked him about the amp. Can't beat that. Thanks, Andy.

[phsyconoodler]

I understand the amp just fine.And when I give an honest evaluation about an amp it's not a slight against the designer.I did say he was brilliant.

That's like saying a heavy metal dude doesn't like a princeton reverb.
It's just not for me.
The owner is as happy as a clam with the changes I made to the amp.
I did try the FET voltage switch and it really didn't make any discernable difference to my ears,but some guys hear better than I do.
We tried several preamp and PI tubes as well and settled on a set of Telefunken pre's and a Tung-Sol PI.
It definitely sounds good now.To him,and that's what counts.

And don't get me wrong guys! I just don't like PC board amps.The Fuchs is well thought out and the layout is dead quiet too.It's just not easy to work on.

So I should just clam up and lie about what I think so it doesn't hurt anyones feelings?
My partner has three models of Fuchs amps;two tripledrive supremes,a Mantis and a clean machine and they are great amps.To him.
I really like the clean machine and he gets all frothy about the Mantis.
The customer's ODS 100 that I worked on did not sound 'right' with single coils and the changes I made made it much better.

I like the switchable cap switch;nice touch.I just wish it would actually do something.
In my experience there is not much difference between 4.7uf and 1uf.The shift starts to become really noticeable from .68uf to just over 1uf
and then after 10uf to 22uf.

I speak my mind.I did not mean to offend Mr. Fuchs.

And I'm in the process of building an amp and guitar factory in Canada in the new year,so yes,I will be a full-fledged manufacturer soon.

[FUCHSAUDIO]

I've been doing this a long time, and it has allowed me to develop "thick skin". I realize not every amp I make will satisfy everyone, however, one of the key elements in business is tact and professionalism. Early on, I had no issue bashing my competitors on forums, and learned it really wasn't cool. My amps stood on their own, and built a business with a sound reputation, and many fans. I didn't need to bash anyone. The products stood for themselves. It went from being called "a cloner" to being called "a gifted builder", no bashing needed. People who know me personally, know that I might tell you what amps I "don't get" or why some "designers" get accolades for cloning and not actually designing much of anything, BUT I don't do it online anymore for plenty of reasons.

In this case: Saying "Fuchs may be brilliant,but I really didn't care for that amp" sounds so much better than "Fuchs may be brilliant,but I can't stand that amp". Perhaps not as much for me, as for you !

Same thing with PC boards. I respect guys like Jelle and Tophat (and many others), who execute amazing works of art in PTP fashion. I don't even prototype PTP anymore. I make boards and cut, jump, and change as the product evolves. For me, it's just easier, since I have to make a board at the end anyway. Little is ever hard wired, other than maybe wiring up a tube to conduct some tests.

As you noticed, the amp is "dead quiet". IMHO, pc boards truly give me consistency, and once the design is stable and quiet, it can be easily repeated. No, it's not the easiest amp to service, but on the other hand, there is little on the board that requires repair or replacment, as the high current things like power tubes, screen resistors, and such, are off board.

I truly don't mind criticism, in fact I've learned to take feedback like this to heart and often it makes it way into future designs. The ODS MK-II has a long list of cool design ideas. The feedback for those changes came from everywhere. Artists and endorsers, right down to the local bar players.

I wish you only the best of success with your factory. If you need a consultant/designer, or whatver, I do lots of that "stuff" for lots of people.

[phsyconoodler]

Yes,you are right.My tone towards your amp was harsh.I do apologize for that.I can be pretty blunt without realizing that it may hurt someone.
Please accept my apologies and hopefully we can forge on with no hard feelings.

[FUCHSAUDIO]

cool

[10thTx]

Yes,you are right.My tone towards your amp was harsh.I do apologize for that.I can be pretty blunt without realizing that it may hurt someone. Please accept my apologies and hopefully we can forge on with no hard feelings.

Phsyconoodler,

Very very cool! Thanks for doing that! I wish more people had that kind of humility and integrity. I truly appreciate the good will and professionalism. And that's just icing on the cake to the great amps you build.

With respect, 10thtx

[M Fowler]

Yes I'm pleased with both parties involved because both are valuable contributors to this Forum and other forums so keeping peace is always a good thing.

Mark