Any Stout w/reverb Tweakers ?

[mresistor]

Just finished a Stout reverb stuffed into a Vox aC15CC1 chassis and wonder if anyone has done any tweaking on the amp circuit.


My thought is there could be a little more distortion available.  I am also including a PPIMV and haven't tried it out yet.


Let me hear your thoughts. What have you done to change the circuit?

[Latole]

You build this ? Any pictures ?

https://el34world.com/Hoffman/files/Hoffman_StoutReverb.pdf

[tubenit]

We need to see an exact schematic of what you have. If it's the one Latole linked to, then I have some suggestions.


With an aim to be respectful of the components in the Stout Reverb design ................. 

I'd add a gain stage   (note the cathode resistor and cathode cap values for each gain stage)

Rewire the tone stack

Move the insertion point of the reverb and change a couple of values in the reverb circuit.


NOT saying you should do this. This is what I would do if wanting more gain.   


With respect, Tubenit

[mresistor]

Thanks for the suggestions Tubenit and yes it is the Hoffman scheme.  I wish I would have had this information prior to building the amp as those ideas may be physically difficult to implement now. Changing some cathode circuits was on my mind.

Yes Latole I have built it, and it had to be vertically flipped and reversed to be used in the Vox chassis with the original Vox iron.  I didn't use the choke so I used a 1.5K dropping resistor off of the reservoir cap. I finalized the pot wiring yesterday and am in process of hard wiring that up today. Because of the way I had to build it the wiring isn't super pretty however it is quiet which I had hoped for. Lack of hum is a good thing.

The reverb does seem to be a little lacking, although it is pretty good sounding it's just not that Fendery Dick Dale level of reverb adjustment

I'll get some pictures of it up in a while.

[tubenit]

I truly have no agenda for you regarding what mod/s you choose.  Having said that, I honestly don't think it would involve much to rewire the Hoffman layout to the mods I suggested.  IF you're interested, take a few minutes and look at the schematic I suggested and the layout. See if you can envision how to mod the layout to the schematic.  If nothing else, it would be a good excercise to do.


With respect, Tubenit

[Ronquest]

Just finished a Stout reverb stuffed into a Vox aC15CC1 chassis and wonder if anyone has done any tweaking on the amp circuit.

Is it an AC15 C1 (2 inputs) or the Custom Classic (single input with or without switch)?   Just making sure, they have different circuits.  If you have the schematic, then even better.
Reread your post, just chassis. 

[mresistor]

Latole - here is a photo of the completed conversion.  If anyone wants more pics and the flipped pot wiring scheme send me a PM with email and I'll send them to you.

[mresistor]

This conversion is dead silent, no hum which is great!

[AlNewman]

Maybe a bypass cap on v3-b?

[ac427v]

I wonder if "not enough reverb" is caused by the small value capacitor for C23 (250pf)?I suspect it blocks every frequency except the high treble.You could try tack soldering in a larger value in parallel (.001 or .002 or .003) to see if it allowed more of the reverb mids to reach the mix control.

[mresistor]

Al and ac   - thanks for those tips..    easy to try ..    a little more low mids / bass frequencies coming through the reverb might help


Jeff   no worries I just need the time to digest the recommendations..   also I may have mispoke.. it's "smoother gain" that would be desireable not more gain..  but I don't have much experience with
high gain amps..  this one has a tad ratty gain with the vol up 1/4 to 3/4 and the mv up to 1/4. 

[waldner]

I built the Hoffman Reverb Stout several years ago and have been playing it recently.  The biggest change I made that really brought the amp to life is playing with NFB and installing a 3 way switch.  I can't remember the exact values I ended up using but they were much higher than the 82K that I think was stock.  Maybe 150K, 300K and no NFB.  The amp sounds great more raw and closer to no NFB though noise increases.


I did also install a PPIMV which is useful for me.