• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

6V6 line preamp

yup. Like i said, ZM and Salas had to nurse me through the change from SS to tube and i did not like my efforts. I bought Lundahl chokes and another power transformer for this go around and will probably increase capacitance as well. After seeing what Stajo went through, I definitely am not confident in my results, but I must admit i am intrigued by Bas' SS/damper diode combo. I will try both just as soon as i can get some breathing room. Beautiful bottles are just sitting there waiting to play music.
 
there are some 100uF Obbligato golds for sell that I am thingking about. About brightness, It is not something I want to clean up, as I dont feel it added anything, but i do not want to speak of it too much until i can confirm that I have a nice clean rail like Stajo ended up with. If it remains then, it is gone. I am not a purist.
 
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Does your PP amp pass a 10kHz square without ringing edges?

Probably not. I've tuned the Z565s with small caps, but atm I have a small motorboating :cool: so its not measurable at all. But its listenable. I went of from attached and did some tuning. I like it very much.

How you realign them when you change HF diaphragms? Adjusting some L-Pad or autoformer by ear?

I should probably not say this but we actually toned it down by putting some glob on the back side of the titanium driver membranes. It helped but not enough so we changed to alu. Titaniums are headache. Also pushed up low mid with a zobel over bass +/-
 

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You got to sort out the amp stable and passing a smooth HF square. Now you have the TDS 340 to help you.

Yes. I was planning to rebuild it but I havent got around it yet. Right now its in some reused chassie with a completely oversized tranny.

About the 6V6 I'm beginning to think that dual SSHVs might be a stupid overkill in anode follower version. It just adds complexity to next to no benefit. I might go with one instead. Whats your opinion?
 
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I cant remember if I have them or not. I have hesitated on putting on the table cause I would probably start to completely rebuild it. But now I have a scope as you say.

Some 100-220 carbons might be a start.

The stupid motorboating just showed up one day. It comes after some playing and doesnt show up without signal in. Its on some half Hz or so and affects the stereo positioning a bit when listening. It goes away if I testchange to ECC81s.
 
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And/or a grid stopper on the return to the input tube's lower half.

I have a 1 k on both halves. I have tried to increase the cathode caps by adding a 470 on the 47 as Artosalo suggested in other thread. Still boating. I just soldered in 2k2s on GNFs but my son wanted some friday movie evening so I didnt have time to test. Later maybe. Thanks.