The Amp Garage

Hey guys, I bought on Hoffman's forum some plastic shoulders that you slide onto the jacks to isolate them from the chassis. Trouble is these are a little too big if you use two pieces (one inside and one outside. I found on an old RCA tube projector these great little piece (these probably date bac...

I tested it, I remembered I had an old HRM board sitting somewhere from a build I rescued. So I plugged it into the normal channel and it worked fine. There is a little signal loss compared to the bright channel but nothing to worry about. I would like that settings to shape the sound when in cascad...

@professormudd if you did Rob's cascade high gain / cacsade mod, you have the following: 1- interactive EQ between normal and bright channels 2- norm chan cascading into bright chan when cascade mod engaged 3-high gain mod on the normal channel You could add the HRM EQ on one channel, but would prob...

Heu guys, Interesting idea... I have been playing with cascading the two channels while trying to keep the original bright channel. So I guess you could add the HRM board to the normal channel in order to voice it differently and tweak for the cascade setting so that the EQ would be switch d only on...

Sorry guys for the late reply, been busy yesterday and could not work on the amp. @Richard1001 yes when I took the measurements, my mains was a low 117, and i had 43v on the bias tap instead of 50v. My setup is as follow : 3k3 dropping resistor > 1n4007 diode > 47uf 160v (as the original Dumble layo...

Oh, yeah. I had #54 around for a bit which is a 3rd Gen. (sort of) and it had a 22k dropper. You could brighten up the preamp by lowering the 27k dropper but you may lose some of that cool organic feel of the lower voltages. I love those darker mid rich tones, good to know that is one way to bright...

@Charlie Wilson, thanks a lot, I hope the build pays respect to your wonderfull generosity, I really enjoy it.
What would be your point on the 27k from the layout ? (just curious )

Fred

Hey Richard1001, Thanks for the advices. I checked and cranked my variac up to 130 VAC and voltages fall inline. My mains was a low 117 yesterday ... Now for the bias, I have 43 VAC current available on the PT. I am using a 3k3 droping resistor and I measured 65mv on the 1ohms resistor to ground fro...

I think I will try and cheat the voltages with the variac and blast it to the max. Funny enough my mains measured 117V when in summer it is around 124v. I guess winter takes a toll on the overall power lines here in Canada. I will try and shoot for the max current and try to hear the difference. May...

Welcome to the forum Lycoming360, There are numerous posts about the different ODS and I suppose listening to the artists that have recorded with those amps would be a great way for you start and forge an opinion on what you would prefer and why. As always with a switching channel ODS, there will be...

Congrats on your build, tight and clean!
Any audio clip to share?

Fred.

@ian @Erwin, thanks guys, I really enjoy the build. But speaking of voltages... I seem to be far away from the goal Erwin's build had the following : Voltages; B1: 440v B2: 437v B3: 413v B4: 283v B5: 276v V2b: 180v v2a: 181v v1b: 173v v1a: 169v bias: 30mA Mines are as follow : (almost 40v shorts all...

Here are a few clips... Beware it was done with the phone so audio quality is not that good.

With a Strat:
https://youtu.be/zJFCs70jYdc

With a Les Paul :
https://youtu.be/SCj0J5j1L_Q

Now I will put this baby back on the bench and check the voltages

Fred.

@Chopsauce yes, but I ran out of those.. so for now it's only ON OFF, but I will switch it as soon as I place an order at mouser

@bepone thanks!

Will try and record a small clip this afternoon.
For now it is family time with the kids.

Cheers,

Fred

Wow super happy with the build. Nothing burned or smelled bad, everything worked right from the start... It is my first build without trouble shooting anything. I need to check the voltages, because I seem to be on the low end. And the PT gets very hot after two hours of playing. Poor Hot Rod Deluxe...