Tube Amp Archive

Do you have room for switches above the pots like two-rock does it?

If not, I would hardwire it in rock mode, PAB switch on the back with a relay and find somewhere for the mid switch. I don't use the bright switch often, so I wouldn't miss it personally.

-Dan

I would do Volume, Treble, Middle, Bass, OD, Ratio, and Master on the front. Presence on the back. Or a switched pot on the master with the older accent arrangement there.

-Dan

PM sent.

-Dan

Glad to see you got this issue sorted out!

-Dan

Hi Wardy, I've continued to follow along, but I am not seeing anything that stands out to me. Maybe to try to rebuild the v1 socket connections and temporarily leave off the LNFB network for simplicity. You can attach photos directly to your posts. That may help more people look at them rather than ...

Thanks for the additional info. Are those measurements you took in AC, DC or a combination?

May be time to try and lift the board to see if anything is amiss underneath.

-Dan

Good luck! And I should have specified, I was suggesting you measure AC on the other side of that cap. Also on the other side of the mid cap. Versus the grid of v1b. Just trying to narrow down where you are losing signal. What changes with the r/j switch with those measurements when in rock, jazz, o...

Can you measure the mv present immediately after the the bass cap, the 0.1uf on your board? Please measure at the leg of the cap closer to the tone stack side of the board. It seems like you have done a great job narrowing down what part of the circuit is the issue. So now we just need to go over al...

Did you happen to take pictures of the underside of your board? You may just need to reflow your solder joints. Have you tried to short out the reverb section to bypass it?

More pics around v1 would be helpful also.

It's frustrating, but I'm sure we can help you get to the bottom of it.

-Dan

There is also the Manzamp preamp built for Eric Johnson:

https://reverb.com/item/73170202

-Dan

... or add the driver from the SSS to the power amp. -Dan Do you mean the gain stage that comes between the PI and Power Tubes? I've been looking at trying something like that but haven't broken ground yet. What kind of effect does that have (ie, more crunch? more PT compression?) I would recommend...

drew wrote: ↑Tue Aug 26, 2025 7:29 am Well, OK, screw you too, “Live Music Archive.”

The site is still up, but old favorited links may not work.

https://archive.org/details/etree

-Dan

You could add the Hi and Low filters from the SSS or add the driver from the SSS to the power amp.

-Dan

I have a question that im sure someone can help me to understand. On the layout above what is happening with the negative feedback? It is different than the schematic, there are many differences, but why is a 5 watt resistor required there? I dont recall ever seeing such a value in a negative feedb...

Looks like the first of three videos from Ben playing this amp.



-Dan