A guy talks about his recent contact with HAD

[Mark]

I guess price point beats amp performance in Fenders accounting eyes. I'Ve heard the WGS 65 speakers sound great in the Blues Junior though people do complain about the cab size.

The idea of using either a pickup or a tape recorder to sense the magnetic field created by current flow is interesting but will the results be a true reflection of crosstalk between components?
how do you distinguish between transformer noise which must be huge and noise from current passing through components?

[talbany]

Those were the changes as I remember them. Keep in mind since this is a single ended Class A dual 6V6 design with one 12AX7, and one GZ34 rectifier tube (not 5Y3 like the original) the bass improved, got tighter and bigger.

Did you notice him using the same value cap there as what was in the original?
If he increased the value of the plate caps (which Dumble has been known to do) That would certainly explain the "tighter bigger" bass response.

BTW. Whenever we would get a new Fender (Deville/Hot Rod Deluxe) in it was common practice to recommend a cap replacement if they were in there. Virtually every customer noticed the improvement and gladly paid for the upgrade..I don't know either if IC was making caps for Fender?.I will say that the IC's we used in the 90's and early 2000's were a marked improvement over the new ones
I wonder if Howie didn't have a stash of NOS IC's in his shop

That is interesting about components talking to each other I remember Dave Funk building an amp which was supposed to be on the verge of oscillation due to cap placement. The idea was to get smooth sustain out of a clean amp. Gil Aron played around with that sort of thing too, he found the circuit worked well at low volume levels but was seriously unstable at high volume, I seem to recall he abandoned this component placement amp entirely.

Dumble has been known to influence positive feedback into a circuit through the routing of certain wires in close proximity to one another...Like Gil mentions these practices have the tendency to make the amp unstable. The trick is knowing which ones you can play with and which ones you can't

BTW.Don't ask which ones go where..I have no idea.

Tony

[Mark]

Dumble has been known to influence + feedback through the routing of certain wires in close proximity to one another...Like Gil mentions these practices have the tendency to make the amp unstable. The trick is knowing which wires to route

The odd thing is I normally place wiring to enhance stability and a low noise floor. Quite the opposite of a small amount of positive feedback. I haven't heard dramatic changes in tone from moving the wiring in Fender and Marshall amps, with the exception of the wiper wire on volume controls. Noise does like to creep in through the wiper of a volume control.

[ayan]

Thanks Jim, it is interesting that HAD was talking about the changes and why they are significant. I had him figured for a guy who would have said change this and that without explanation.The real tragedy with guys like HAD is the stuff they learn isn't passed on to others. Still I suppose he did the hard yards.

That is interesting about components talking to each other I remember Dave Funk building an amp which was suppose to be on the verge of oscillation due to cap placement. The idea was to get smooth sustain out of a clean amp. Gil Aron played around with that sort of thing too, he found the circuit worked well at low volume levels but was seriously unstable at high volume, I seem to recall he abandoned this component placement amp entirely.

Not sure about the grounding, but the capacitor composition and placement have been issues for me in the past. I had an early mod that sounded amazing, but oscillated at high gain settings. I added some copper foil to a coupling cap (which was near another) and grounded it, and it fixed the issue. I'm pretty OCD about my board layouts and grounding because parts talk to parts and there are subtle aspects of the tone that will suffer ! Take a guitar pickup on a cable (not on a guitar), plug it into another amp, play guitar (or pass a signal through the amp you want to test) and hold it over wires and components, and you will see what I mean....

I assume you mean a single coil pickup as opposed to a humbucker as signal isn't induced in the pickup by a string cutting the magnets lines of flux and the humbu king coils would cancel out noise. An aluminium or stainless steel chassis would be a must so you don't pick up noise from the transformers I imagine.

Who's this Gil Aron guy you speak of, Mark?

Cheers,

Gil

[Mr. dB]

... I always know who Dumble is making amps for, a doctor from Arkansas, who flew in on a plane on a Friday and left Sunday morning, because his Fender Deluxe mod and his Magnatone amp were ready...after 10 years.

Oh, Gil's got a Deluxe now? I remember when he finally got his ODS, I think that was only a three year wait. That would have been around the end of the 1990s.

One time his band was learning an old Jeff Lorber Fusion song, so he flew them all out to LA and had Jeff teach it to them.

[Mark]

Who's this Gil Aron guy you speak of, Mark?

Damned spelling mistake, sorry about that chief.

[Mr. dB]

... I always know who Dumble is making amps for, a doctor from Arkansas, who flew in on a plane on a Friday and left Sunday morning, because his Fender Deluxe mod and his Magnatone amp were ready...after 10 years.

Oh, Gil's got a Deluxe now? I remember when he finally got his ODS, I think that was only a three year wait. That would have been around the end of the 1990s.

One time his band was learning an old Jeff Lorber Fusion song, so he flew them all out to LA and had Jeff teach it to them.

And then there's the time he loaned his ODS to The Rolling Stones for a session. It came back with cigarette burns in the suede. The good doctor was beside himself with anger.

[ayan]

Who's this Gil Aron guy you speak of, Mark?

Damned spelling mistake, sorry about that chief.

Ha ha, no worries, mate. I was wondering for real if there was another person with a similar name. Good to see that you're still enthralled by the art of amp building. I'm still hands off, it's been about 8 years since my last full build and I've gotten so lazy that I'm even thinking about having my next pedalborad professionally wired for me.

I listened to the podcast with Bruce Forman referenced earlier, where he talks about his adventures with Dumble, having him do the Ultraphonix mod to his Vibrolux -- I think -- etc. Interesting stories. Forman is a wonderful guitarist, I remember seeing him a few times in San Francisco in the 80s when I lived up there, and it was a jaw dropping experience. He would be, however, about as far as I would have imagined from a candidate HAD customer.

Cheers,

Gil

[Scumback Speakers]

Around 18-20 years ago when I met Howard, there was a requirement to play for him, or he had to hear
you play live before he would agree to build you an amp. Then came the dreaded wait for said amp.

[ayan]

Dumble has been known to influence positive feedback into a circuit through the routing of certain wires in close proximity to one another...Like Gil mentions these practices have the tendency to make the amp unstable. The trick is knowing which ones you can play with and which ones you can't

BTW.Don't ask which ones go where..I have no idea.

Tony

Hey Tony, in the end, what happened to "Feedback City"?

G.

[talbany]

Hey Gil

You mean this ole piece a crap!
https://www.youtube.com/watch?v=qyB4HedEOvs

Traded it for a Tube Screamer!..
Kidding.Sold it to a friend. Made me an offer I couldn't refuse.
Right now working on a low plate skyliner Music man.Will see if I can do a FBC Mk2.
Hope you are well!
Tony

[Matt J]

And then there's the time he loaned his ODS to The Rolling Stones for a session. It came back with cigarette burns in the suede. The good doctor was beside himself with anger.

Ha! Man, I bet he was pissed! I think that kind of stuff would come standard when you loan stuff to The Stones, though. I would love to have heard Keith and Ron Wood through an ODS too.

- Matt J.

[brewdude]

I would think a Kieth Richards cigarette burn would add value...
It’s hard for me to imagine Kieth or Ron Wood using a Dumble amp.

[erwin_ve]

Dumble has been known to influence positive feedback into a circuit through the routing of certain wires in close proximity to one another...Like Gil mentions these practices have the tendency to make the amp unstable. The trick is knowing which ones you can play with and which ones you can't

BTW.Don't ask which ones go where..I have no idea.

Tony

Hey Tony, in the end, what happened to "Feedback City"?

G.

That was an epic thread; 10 pages of mystery and no clue..

[talbany]

and no clue

Erwin
This is not entirely true
Some clue's we got from the FBC amp were?
1.It was being generated somewhere in V1 since it did it Clean mode and not in the output section
2.it' didn't seem to be too picky about tubes either!
3.That amp had no NFB on V1
4.The amp did have the caps oriented foil to gnd (after later inspection )
5.V1's Filter cap was down by V1.
6 The amp did have a 68Pf bright cap on the master vol
7.The amp was a HP Skyliner. and loaded micas not ceramics
8.High-quality resistors and NOS CTS Pots (2-35) were used..(No Xicons/Alpha's)
9.B+1 Filter was 50uF not 100uF
All of these factors I believe did play a role although we could never actually track down a single"smoking gun" Perhaps it was a combination of several of these clues I listed

The FBC amp was the last amp I built so I am anxious to see if I can do another one that responds similarly in this next MM amp I am building.We'll see.
Tony