The Amp Garage

eddie25 wrote:I I then switched the OT primary wires and hooked up the NFB again and the amp sounded even worse than before.

Revert back to original connection of PT primary. You created PFB which is a sure fire way of turning a good amplifier into an even better oscillator.

Guess what main ingredient of the electrolyte in the caps is. Yes, it's water. You heat it up it evaporates. Read up on app notes from serious manufacturers, they all advise to keep the caps away from heat sources, they warm up due to current passing through them. The data sheets also show how the c...

There is a common confusion/misunderstanding of what anode (plate) load line represents. It is not a characteristic of how the anode (plate) behaves but how load ON the anode (plate) reacts i.e. it represents current drawn by the plate (anode) resistor from B+ supply as function of all B+ values ava...

It's the number of turns not resistance that counts. I'd be concerned if inductance of primary sides differed significantly.

No liquorice, R.G.?

Have tried to tighten the bolts holding the core together?

I've built a few pairs designed by Mr. Bailey published in Wireless World in 1972. I sold my own pair which I regret...

So why not take the plunge and use a toroidal OT as well?

I built several variations of this amp, and I still have one with this MV, which is very similar to the Carlsboro and Mojave MVs: [img:1024:698]http://i514.photobucket.com/albums/t346/jaxmoons04/talon_schematic_1.png[/img] I have mixed feelings about how it sounds - sometimes I like it, but usually...

Variable cathode resistor in LTPI? Have a look at some old Gibson schematics.
A gain stage between sections of 2 gang pot? Peavey and others.
USPO should be on "Ridiculousness".

2xEL34 on 400V for ca 45W output power or on 500V for ca 70W.

The "driver" transformer is the phase inverter driven by the 6V6 SE stage. The PP output with 2xKT88 (originally this amp used GE 6550 ruggedized version made for Fender) operates in class B2 courtesy of the PI transformer supplying enough current to the control grids. This together with 700V on pla...

Want hum free hi-gainer? Use separate transformer for preamp heaters. Well filtered DC and put the heaters on some 50-70V DC above ground.

Do I understand correctly that you changed ALL capacitors circled in your schematic between the tests? If so, this invalidates your conclusions as you have no way of knowing where in the circuit the most significant change occurred. Also, with 10% capacitance tolerance i.e. it can be 10% over or 10%...

That goo is the electrolyte in gel form. It's what makes it work. At working temperature it liquifies. It will leak out. The electrolyte will spread all over amp's innards. The cap is junk. It's terminally ill. Read detailed data sheets, the part dealing with handling and application notes. It says ...