Out board power amp

[nwguy]

I just finishded building a power amp using the circuit of the Showman Amp. I included the phase inverter, the .01 cap going into the PI grid and the 4 - 6L6's and output trans. The resaon behind this is to use my Delux Reverb as a driver and get some extra volumne and Headroom.
The sound is muffled and distorted
All voltages chech out ..........any ideas ?

[Don Symes]

You'd better not be using the DR's SPEAKER output to drive this thing!
Please describe how you're connecting the two.

With no SPEAKER connected, you can cook the DR's output section.
You would also be overdriving the power amp's input like crazy (possibly doing damage).

If you're not doing that:
Keep a speaker connected to the DR - that load is required even if you're not really using it.

Consider adding an input stage to your power amp - a pair of triodes in parallel, say - as a buffer; and a volume control. You need a bit of gain before the PI, but you want it controllable.

Hope this helps!
(don't mean to sound like a tool, but I've seen even smart, experienced people do some alarming things.)

[nwguy]

Here's shat I did

Thanks Don,
I have come out of the external speaker jack into a direct box. the original speaker is still connected. from the do box I go into the power amp.

Craig

[Amp Kat]

Don is right on the money, that's not going to work very well either and can also cause serious damage. Where is the power amp IN point at ? A direct box is nothing but a transformer changing impedance but has no power limiting effects. So impedance is not a big concern but power is. If you are coming into the PI it's not going to work as that is a low power point and could fry the PI tube. I'm not a fan of these type connected amps although I know they do it in Arena fashion but IMO the connection to make it work would have to be internally connecting the two output transformers together on the secondary side for a boost type. You'd be much better off for you and your amps if you just get an A/B/Y box with isolation transformers and use either both amps at one time thru signal splitting or one amp at a time or vice versa.

[Don Symes]

Thanks Don,
I have come out of the external speaker jack into a direct box. the original speaker is still connected. from the do box I go into the power amp.
Craig

Direct boxes can be a good choice, but they expect to be driving a low-level preamp input. Try connecting a stereo line out (Tape RECORD/TO output?) to your power amp input to see if you have enough front-end gain before the PI.

If the chassis are going to be close together, think about a special cable running from the last stage before the DR's PI (you'll want a separate AC coupling cap in the DR before this cable, and a 1M to GND at that node) to the power amp's input that you have now. The cable should be shielded, but be prepared to cut the shield at one end if you run into ground-loop hum.

Overall, though, I don't recommend this approach - adding a gain stage or two to the power amp will help - hell add a whole preamp and jumper to the bigger amp from the DR's second input jack.