Looking for this amps builder

[Mule Train]

Looking for the builder of this amp. In the last picture you can see some writing in the bottom left corner.
Any help would be appreciated. I’m looking to throttle the gain back, as I was told it was a ultra high gain build, per the owners request. For some reason I wanna say Dan Hall or Skyboltone (not Dana or Richie) is a name associated with this. I am not sure about these names and could be confusing everything....
Thanks for any help

[xtian]

Can't help with the builder. But for starters, do you have 12AX7s in all three preamp spots? Lower gain tubes, like 12AT7, are a good place to start without having to solder anything.

[Mule Train]

Can't help with the builder. But for starters, do you have 12AX7s in all three preamp spots? Lower gain tubes, like 12AT7, are a good place to start without having to solder anything.

I came up with this:
“Dan Hall (Skyboltone) on the Amp Garage built it for me.

It's an Express circuit with 2 7189 tubes. They're basically a high quality el84m. Don't use 7189A tubes. Those have a different pin out and you'll break something (amp or tube, I forget).

I spec'd the amp with metal film resistors for lower noise. And asked Dan to up the gain for me. (I think that's where the "Little Fool" name came from...me asking for a higher gain Express.

The faceplate and logo came from another Amp Garager I forget who. The cabinet came from a TGPer I forget who.

I love that amp and really miss it but I've had some trouble with my hearing and can't chance it with that monster.

That amp puts out about 25w at full tilt. Run vol/bass/mid/treb at 1 o'clock...presence about 9-10 o'clock. I like the bright switch on its darkest setting. Then run a volume pedal between your guitar and the grin of the amp. I never even tried pedals.

The output tranny is set for 8ohm loads...I ALWAYS attached it to 8ohm.

It's got a toroidal power transformer. There's also an "extra" transformer...that's the heater tranny to get the 6v (heater supply) separate from the rest of the power...it will help quiet the amp. “

So that makes it sound like it was a build that was high gain and was wondering what options I might have to throttle the gain back some.

[martin manning]

Skyboltone hasn't been around lately... no posts since fall 2014.

7189A will sub for 7189. 7189A has higher screen voltage rating, and the internal connections from pins 1 and 6 are specified (1 connects to 2, which is g1, and 6 connects to 9, which is g2). Looks like 7189 also had internal connections to those two pins, they just weren't identified. You are absolutely safe with the substitution if there are no connections to pins 1 or 6 on the sockets.

You could substitute 12AY7 for V1 and get a gain reduction of about 6dB. I would trace the circuit and compare it to the standard Express to see exactly what has been changed.

[10thTx]

You can put a 12AY7 in V1 and a 12AT7 in the LTPI V3. That should lower the gain considerably.

With respect, 10thtx

[Mule Train]

Great info, thanks for the replies!

[M Fowler]

This amp was built around the time we all were interested in building a DLM Trainwreck.

Mark

[xtian]

You can put a 12AY7 in V1 and a 12AT7 in the LTPI V3. That should lower the gain considerably.

With respect, 10thtx

Owner Mule Train brought this to me for a look. As you and Martin suggested, I replaced V1 and V3 as spec'd. This helped a bit, but not enough. Next I added a 1M trimmer to create a voltage divider with R7 (150K), just prior to V2a. Turns out I didn't need a trimmer, because a resistance of 1M was best there, dumping 87% of the signal to ground. Major improvement. Now we have some clean gain on the volume pot to work with, up to about 9 0'clock on the dial. Then, onward to high gain goodness.

[lumox0013]

thanxx for the update xtian always looking for the next puzzle piece .
just curious did you go back to 12ax7s after the adjustment?

[xtian]

No, I left the lower gain tubes in place.

[Mule Train]

No, I left the lower gain tubes in place.

Whatever wizardry was performed, it is amazing!
I played until I thought the cops would be called last night and today, for the last hour. Just stopping to post an update and a thanks to xtian for transforming this amp from a storage dweller, to riding high on a 4x12 filled with 20 watt greenies. Can’t get this smile off of my face.
FWIW I played thru an ODS build of xtian’s also, and it was phenomenal.

[pompeiisneaks]

No surprise there, xtians stuff seems outstanding to me, I've heard some of his playing too, it's damn good as well (that video he posted here a bit back was great listening).

~Phil

[skyboltone]

Yup. I built that sucker. It was a runaway for sure. Nice touch dumping all that gain with the megohm shunt to gnd. I built another one for a guy and subbed in a lower plate resistor on the clipper. It tamed it a bit but it needed more. The guy who commissioned the amp was really sold on the toroid PT otherwise I wouldn't have used one because they are not center tapped and you don't have filament voltage so that's why you got three transformers. The output transformer is a Hammond organ unit that's about 8K if I remember right? Fun build but I would use a standard style PT if I made another one and make the clipper stage plate resistor variable like a drive control. A hunnert K or something. I have several of those Hammond trannies.By the way; nice lookin box on that. I just shipped it out bare chassis.

Dan