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Massive quad 6l6 mono amplifier

Maybe opt for a single US-made 5U4GB or go solid-state rectification. Those early 5U4G and GA tubes were notorious for not wearing out evenly in dual rectifier setups.

I love the sound of the 6L6G (GA) coke bottles. It's getting hard to find healthy, quiet ones. They have a quality between the 6V6GT and the 6L6GC — which is good in my book. :thumbsup:
 
I kinda like the metal 6L6 tubes. You can find NOS ones for a lot less than 6L6G tubes because they are nothing to look at, but I'm cheap and my one 6L6 amp is in a console radio where I can't see the tubes anyway.
 
The power transformer alone would probably cost $200. 800 volt CT with 5v winding for 2 rectifiers and a 6.3 volt winding sufficient to power the amp and the tone box 6SN7s.

Another member on this forum changed the output transformers and used 6550 tubes for 100 watts rms output.

The paraphase inverter would be better if converted to floating a paraphase. Disregarding balancing and changes due to tube aging I think a paraphase vs LTP is a matter of taste. The paraphase will generate more even order harmonic distortion. The LTP will cancel it.

I like the small amount of even order distortion from this design. I think that is one of the reasons that the paraphase splitter magnavox amps are so popular.

Steve
 
I tested 6 of these output transformers. The turns ratios on the two taps are approximately 15 and 20 (a few tenths higher). Into 8 ohms that will be 1800 and 3200 ohm primaries. Into 16 ohms that will be 3600 and 6400 ohm primaries.

Looking at the spec sheet these were probably driving 16 ohm loudspeakers.

Steve
 
There are no hf frequency response limiting parts (apart from the anode stoppers), so if you can do a frequency sweep then that should give you an idea of output transformer response. Given there is feedback, you can also quickly check how much feedback, as well as do a squarewave test to see if there are any noticeable hf resonances to support the frequency sweep.
 
steve... said:
This is the schematic for the amp Carbsand Caps posted.
Click to expand...
my mistake, that other one looks similar but no extra voltage amp stage.

A floating paraphase makes more sense in this one since there isn't that extra tube to play with. easy enough mod, and it fixes many of the shortcomings of the standard paraphase.
 
the green "fuzz" on the sides of the chassis, might be cadmium deplating, if is is, dangerous, please use care. use a mask and gloves when wiping it off.
 
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