Showman UP

[Smokebreak3]

I've got a bandmaster here that I've been given carte blanche for the vibrato channel, so 4 stages on hand.
Is there a general consensus as to what the topology is on this one:

https://youtu.be/GQS7nzshOvw?si=QzkfzOLfk1iUKIpL

Certainly it's not the 3 stage fendery tweaked UP design(which is great! but nowhere enough gain)

[WhopperPlate]

In a recent thread discussing this very amp Andy Fuchs ( who is playing in the video) states that this amp needed to be turned up pretty high to give up the goods . Not exactly a gain monster.

[jelle]

Dumble Ultraphonix Fender amps follow the original topology, the topology of the donor amp, in the case of silver and blackface amps.

This amp is 2 gain stages before the phase inverter, like the donor.

If you see any cascaded medium to high gain master volume amplifier marketed or presented as an Ultraphonix, simply walk. Its not an Ultraphonix. instead, it could be based on one of Dumble's many other mods he had, some never received names, but an UP its not.

Dumble UP amps have the UP decal on them, a very distinguishing feature that sets them apart from all his other mods.

The reason why this amp in the clip distorts is because its cranked.

[amplifiednation]

There is also the Ultraphonix and Gain, which is a two channel setup...but the Ultraphonix channel doesn't breakup until cranked (as noted)...it has no MV...but it does breakup really nicely with some volume. There are two inputs on these amps and each channel has it's own EQ.

There are several variations of the Gain voicing...there is an AC/DC style rock voice, and also a modded EVH brown sound plexi...maybe some others...

[jelle]

The Marshall circuit based mods by Dumble are interesting and diverse.

I have played a few. First one was a Marshall plexi that had a master volume, and sounded just like Kossoff, it was amazing to witness. Second one was a modded Fender amp and it was much more modern sounding, smoother. The third one I heard was a non MV mod to a Plexi and it was very big sounding, sounded wide open in its frequency response, and not harsh at all, very lively. The fourth one is a JCM900 non reverb that was completely rebuilt, and is high gain, with tremendous clarity, drive and note separation. I bet Slash, Angus Young, and EVH would have a field trip with this one. And compared to a HRM Overdrive Special, this amp has so much more going on when given some drive. I'd say that I prefer it over a Dumble HRM.

I bet there are more versions that I have not seen yet. Very fun amps, every single one of them.

[WhopperPlate]

The Marshall circuit based mods by Dumble are interesting and diverse.

I have played a few. First one was a Marshall plexi that had a master volume, and sounded just like Kossoff, it was amazing to witness. Second one was a modded Fender amp and it was much more modern sounding, smoother. The third one I heard was a non MV mod to a Plexi and it was very big sounding, sounded wide open in its frequency response, and not harsh at all, very lively. The fourth one is a JCM900 non reverb that was completely rebuilt, and is high gain, with tremendous clarity, drive and note separation. I bet Slash, Angus Young, and EVH would have a field trip with this one. And compared to a HRM Overdrive Special, this amp has so much more going on when given some drive. I'd say that I prefer it over a Dumble HRM.

I bet there are more versions that I have not seen yet. Very fun amps, every single one of them.

I think I remember the guitar wank podcast talking about that jcm900. If I recollect correctly they mentioned that it was essentially kept stock from original schematic, no?

I am a Marshall guy at heart , and that Marshall ultraphonix clip that floats around always gets my panties wet

[jelle]

I would love to see that video on the JCM900. The one I mentioned is one I own. I always wondered if there are more of those, I bet there are....

[Smokebreak3]

Thanks y'all I built a 124 preamp into the vibrato side(he didnt want the verb), and after tweaks, it sounded great , even with a standard 12at7 Fender PI.
He needed that for a stock Fender sound out of the normal channel.
But man, I was really temped to talk him into letting me go all the way with it, as you could really feeeeel the amp start to take off into feedback and crazy sustain, when it got loud, even with the 12at7 PI
It was on the edge of the cliff, so to speak. Great amp all around though, still. It was for a pro country guy, his recording amp, I'll post a link when it's on the radio!

[WhopperPlate]

Thanks y'all I built a 124 preamp into the vibrato side(he didnt want the verb), and after tweaks, it sounded great , even with a standard 12at7 Fender PI.
He needed that for a stock Fender sound out of the normal channel.
But man, I was really temped to talk him into letting me go all the way with it, as you could really feeeeel the amp start to take off into feedback and crazy sustain, when it got loud, even with the 12at7 PI
It was on the edge of the cliff, so to speak. Great amp all around though, still. It was for a pro country guy, his recording amp, I'll post a link when it's on the radio!

I like the stock fender PI. Keeps things articulate and tight . Helps balance those preamp values , which I find to have a certain bouncy chewiness that doesn’t knock as hard as a stock low plate design . Dumble PI values make things loosely goosey and feedback easy . 2 cents