Finally Plexi 6V6 build

[JoeCon]

Miles

It was tough stuffing a Plexi into a TW 17" chassis...

[sluckey]

It takes some careful planning to stuff one into a 12" chassis too.

http://home.comcast.net/~seluckey/amps/ ... 6V6_05.jpg

[M Fowler]

Nice one Slucky.

My 50w JCM800 2204 into Fender Champ chassis

[JoeCon]

OK, it's alive.
Voltage is high, was expecting 575V and getting 610, so measuring 405 on the plates and screens. Edcor unit and they have always been a little high but this is a lot.
So 6V6 12 watt tube, 405 Plate voltage so about 30mA is 100% dissipation correct? SO I want down around 20/21 mA for 70%.
First fixed biased amp so I'm a little slow on the uptake here...

Also still get sound thru with volumes on zero, wired wrong??

Thanks...

[Colossal]

If you are using JJ 6V6s, I wouldn't sweat 405V at all. I've run 440-460 VDC on them with a long service life and not one failure. The thing though is to drop the screen voltage under those conditions. At 440VDC, I think mine was biased around 17-18mA, IIRC. Sounded huge.

[JoeCon]

Dave

So increase the 1k screen resistors to drop some more voltage?

It is huge sounding and got a '68 or '71 switch for the bright channel.
Haven't tried the 5000pf over the volume yet, but I will. Nice being able to mix the two channels from the volume controls...

Thanks...

[Colossal]

Dave

So increase the 1k screen resistors to drop some more voltage?

It is huge sounding and got a '68 or '71 switch for the bright channel.
Haven't tried the 5000pf over the volume yet, but I will. Nice being able to mix the two channels from the volume controls...

Thanks...

In my amp, I used a choke with series resistance AND 1k screen resistors. There was a 40V decrease in B+ Plate to Screen supply with the choke and resistor. Yeah, it's a great amp and a very loud 22W. Your '70s era bright cap value might depend on what coupling cap you used on the bright channel. Mark used 0.0047uF for the bright channel cap in his build and so did I.

[JoeCon]

Dave
Yeah I did the choke but no resistor, should add that.

Went with 820R or 2k7/680nf with an .002 coupling cap.
Need to make the .680 on v2a also switchable.
But first I wanted to be sure it worked!!

Thanks again...

[JoeCon]

OK
Pot connections, hope these are right. JJ 6V6...
Cab from RJ, thanks...

[Colossal]

That is a box of Rock right there

[joeboo88]

That's awesome Joe

[Bob S]

Man is that beautiful Joe!
Honeymoon time - give her hell.
Congrats,
Bob

[JoeCon]

Gentlemen

Thanks guys, I had a lot of help from you and others here.
Changed up the screen resistors to 3K-3 watt and that helped some. Need to get another dropping resistor after the choke and before the screens.
Also found 550pF bright cap on the mixing resistor microphonic and changed that out. Much better...
Will try some nice old tubes someone sent me ( Thanks Bob) in the preamp slots next week. But now she just cranks. Using a G12H and Vintage 30 and it fills up the space easily. Bring on your loud drummer.
Friends joked on FB..."does it go to 11?" No but it sounds like it's on 12!!
One Loud amp....