The Amp Garage

Looking at the voltages, something’s off. It’s hard to tell, because this is a modified circuit so I’m not sure the function of each tube. Do you have the schematic? If not, a description of the amp and tube function, I.E. V1 preamp, V2, reverb, etc. I’d suspect that one of the 12AX7s is incorrectly...

CHIP wrote: ↑Mon Feb 07, 2022 11:44 pm As I recall, although I may be wrong , but I think #183 was biased on the cold side.

Scott Lerner suggested bias at about 35ma, but I’m not sure what amp he was talking about. I run my 4x6L6 blues master at 52ma. Unfortunately I can’t ever crank that amp up, which is why I built the little one.

Sounds WAY better, both in clean and OD. I don't know what power tubes you have but I find with new production you have to bias them up a bit to fill out the mids. All of the real Dumbles I have had my hands on were biased pretty warm by him. CW I originally built this amp for 6V6s, deluxe iron, bu...

xtian wrote: ↑Sat Feb 05, 2022 7:38 pm Bob! Nice!!! Great singer, too. Play that demo for me blind, I might not notice it’s a tribute band!

Well…the singer is gone. Great voice and stage presence but he couldn’t remember the songs.

Glad you enjoyed it, we work hard.

I finally had the chance to use this amp in a band setting. My Allman Brother tribute band had a rehearsal in a nice venue with a good sound system. The chassis was installed into a Princeton reverb cab with a 12” WGS ET-65. Yes, a 12 will fit in a Princeton offset away from the trannys. I setup my ...

Ben Harper looked like he was gonna kiss that Lindley amp.

Don’t forget, I made a bunch of lead dress changes too. Every change made small improvements. Of course the biggie was the bias being way off.

Note to self, start with the basics.

drew wrote: ↑Sat Jan 22, 2022 1:26 am Bob, when you get it where you want it, a “before and after” sound sample would be interesting, if you have the time.

Here’s the after…

https://drive.google.com/file/d/1LqAEmk ... p=drivesdk

3.Bias; youre sure your not underbiased? It could cause what Im hearing in the soundsample. Erwin Ding ding ding ... we have a winner. My mistake was thinking the clean sounded good so it couldn't be in the power section. My notes from when I built this amp said "plate=383v, bias=48ma". When I chec...

Hi Bob, good to see you back! You made me do my Peavey VT conversion to HRM 12/13 yrs ago! Anyway looking at your pics: 1. The ceramic cap to tonestack; Is this a X5F type? X5F remains smooth even when using drive, a lot of other types have a nasty overtones that pop out during overdrive. 2. On the...

fI spent some quality time with this amp today, reworked the lead dress on V1 and V2. Very subtle change in tone, and the fuzzy ness is still there.

mojotom wrote: ↑Thu Jan 20, 2022 6:41 pm 6V6 power amp ?

Well…yes and no. It’s using Princeton type voltages, but I have 6Ls in there now,

Thx for taking the time to look. @bob my opinion, what i see... 0. remove the capacitor from OD pot..no need 1. cathode wires usually going under the board, not over 2. anode wires usually going under the board, not over 0. The cap was tacked in to see if it would help. I’ll pull it off, it didn’t h...

talbany wrote: ↑Thu Jan 20, 2022 1:49 pm
Hello Bob
I had a similar problem with my HRM's do you have any pictures handy?

Tony

Thx Tony, pics are posted above, as is the layout. I may have changed a few things after assembly but you get the gist of it.

base of the sound is ok... try to remove all bright caps from the first volume pot, and put simple vintage brown ceramic cap 470pF 500-1000v for the treble control.. also to put carbon film in od section.. resisitors in od circuit can be increased from 100k to 150-330k to the drive pot according to...