The Amp Garage

unlike the ELs a 6CA7 is a beam type power tubes like a 6L6GC and will bias in real close to EL34. The best made and sounding 34s right now are JJs, very punchy and not brash on the top when pushed to clipping, and the groovertubes version of the JJ (EL34S) has been up rated with beefer plates to a ...

If the preamp tube sockets are mouted on a circuit board its likly that a solder connection has gone bad due to heat up and cool down sessions. If this is the case you will see a full or partial ring around the tubes sockets pin in the circuit board trace. use only a leaded type solder to fix this o...

The groovetubes version of the JJ EL has been uprated to a 30, watt from its 25 watt rating by adding extra plate mass to its structure, heay wings as they call them. Also a true 6CA7 plays different than a EL as its a beam type tube and as such in amps with out a feedback circuit you can really hea...

With the silver face and these reissue blackface amps the plate voltage on the output will be some 380 to 403 volts dependant on the how strong the output tube is.

Rewire the heaters like a good amp (two well twisted wires), no one leg of the 6.3 volts landed to the chassis like the way they come. These amps run a ton of plate voltage( way out of class A) even with the 5y3 recto and idle with a good 6v6 way above 40 ma. If you want to keep the 5y3 recto and no...

You can not get 100 watts out of 2 6l6s unless the amp class AB2.

If the preamp, or any tubes are mounted right on a circuit board then one or more of the solder connections (tube pins to circuit board trace) has factured. This will be the most likly cause, so break out the soldering iron and use a leaded type (vintage if you will) solder if you can as leaded type...

Does the amp you will be using this thru have a effects loop?
Time based effects like reverb,chours and echo sound like crap when they get added in thru the front of the amp and then distored by latter stages.
Amps with built in effects add these in almost last, right before the power amp.

You should post up what type of music your into playing so you get relevent ideas.

The insulating film is made from pertroleum and labor cost are going up.

those blackface amps could have been fitted with a 5AR4 recto, or a 5U4GB, both set up`s use the same power transformer. The 5U4 recto should not pump into more the 40 uf of filter cap, the 5AR4 can handle 60 uf of filtering. If your current recto is a 5U4 replacing it with the lower impeadance 5AR4...

A while back I had been bringing back to life a guys 1979 Hiwatt 50 and also had on hand for one of my own amps a set of new JJ 6V6 outputs. Here are the wattage output results from resetting the amps bias for the JJs and testing the amps RMS power into a resistive load. Speaker ohms Imp switch RMS ...

All your preamp tubes voltages seem fine, if you want a bit more preamp tube dirt sooner with a tad less tp end responce, than add 5 to 7k more resistance to the second power supply dropping resistor and make sure its at least a 1/2 watter.
If I recall right this resistor in a stock 5E7 is 10k.

So I guess you had a DR103 with weak output tubes if all eles was wired right ,like the impeadance swirch,

If your measured audio signal across the outputs tubes pin 5 is more than about 36 vac, than you are drivin the crap out of the 6v6`s and the compression will be quite large and the distortion could be unpleasent depending on the brand of tube.