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my 300B SET project

Hi Dave, I did the same mod just before Christmas! The sound is very good. I feed my 300B amp directly from my music server to the shunt level controller. The only problem is a very limited range of control, but with some tweaking, I'm sure I could resolve it.
 
Vincei, are you using an attenuator for volume control? With my Alps 100K pot and 51K resistor I have the same level control as I did before the mod. All resistors in my amps are Kiwame. To make the volume work the same though you have to install the pot backwards in the circuit to make the taper work the same way. I was telling SET12 that the mistakes in the recordings really show up now, you simply hear everything!
 
Hi Dave, yeah I may have wired it wrong, it does sound good, the details are more apparent now, of course I am eliminating my active preamp, so that may also help. This tweaking is really addicting....
 
I linked this amp build back on tube audio tonight. I just spent over an hour listening to Emerson, Lake & Palmer and then Rene Fleming's Dark Hope. The dimension to the music is simply awesome. Of all the things I've built these amps are very close to the top of the list.
 
These amps are probably the best thing that I've spent money on in several years saltwater. I'm still interested in playing with different OPTs but would be satisfied if I never touched them also.
 
Every once in a while, I don't know what it is. The moon phase is just right, the barometric pressure makes for better sound, the humidity is perfect, the temperature is right, who knows. I listen to these amps a lot but tonight was pure magic. Why is that?
I started out with Patricia Barber, then Allison Krauss a little Robert Plant and finished up with Lobo. That was 2 hours of pure bliss.
 
Sounds like fun. I feel the same way, sometimes it's fine others just fantastic! I think it may be me though..LOL
 
I read the thread, but may have missed what kind of OPTs those are? I'm also curious as to idle current if you have the info handy and want to share. Thanks, jay
 
jaymanaa said:
I read the thread, but may have missed what kind of OPTs those are? I'm also curious as to idle current if you have the info handy and want to share. Thanks, jay
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OPTs are Hammond. I'd like to try some Plitrons but they are about a grand right now and that's a lot of cash to spend if you don't know what you'll get. Idle voltage at the end of the 300B? just under 450V. 250V on the last 7193.
 
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You'll get just about the best output transformers made. Likely with better extension on both sides of the freq spectrum.
 
Dave C said:
OPTs are Hammond. I'd like to try some Plitrons but they are about a grand right now and that's a lot of cash to spend if you don't know what you'll get. Idle voltage at the end of the 300B? just under 450V. 250V on the last 7193.
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You might want to consider the O'Netic's iron, I know several people that have switched and are quite pleased with the results.

Best Regards,
TerryO
 
dnewma04 said:
You'll get just about the best output transformers made. Likely with better extension on both sides of the freq spectrum.
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dnewma04, are you saying the Plitrons are that good? My research indicated they are tops but I have not heard them.
 
The best tube amps I've heard used Plitrons. That combined with specs that are nearly unbeatable makes them a bargain in my mind when compared to Tamuras, Tangos, and some of the other high end alternatives. I've never heard Bud Purvine's O'netics transformers but I have heard good things.
 
Can't seem to find Bud Purvine's O'netics transformers in Single-Ended designs, do you happen to know where they could be found?
 
Greetings SET, I could not find O'netics single ended either. The web page seems to need some work though. As you may gather I'm still looking hard at the Plitrons.
 
As I saw it posted on another forum a guy said Plitrons were used on the best tube amp he ever listened to, very extended. He also said " I would u$e them if I wa$ building one of Tho$e amp$ !! I thought that was funny.
 
Good question about the O'netics, I know that Bud and many of his audiophile pals have moved away from SET to PP triode amps, so I'm not sure that he is even making SE transformers.
 
dnewma04 said:
Good question about the O'netics, I know that Bud and many of his audiophile pals have moved away from SET to PP triode amps, so I'm not sure that he is even making SE transformers.
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Thanks, But no PP for me I'm a SET man. Even a good PP after awhile will bore me to tears harmonically. BTW remember the 100 ohm resistor comment I made and you commented on the sound being more dynamic because of the 15VDC raising of the B+? Well, I conducted a test with another very experienced musican-listener-Audiophile. And I will be writing on the subject of what we found probably in my power supply thread.

Dave C said:
As I saw it posted on another forum a guy said Plitrons were used on the best tube amp he ever listened to, very extended. He also said " I would u$e them if I wa$ building one of Tho$e amp$ !! I thought that was funny.
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Guess they have to be heard as opinions do vary :yes:

Was he referring to a SET or PP. :scratch2:

I got an e-mail from AKer Rage and he tried a set of SE Torrids

"I'm just about to dump the tomiko SE toroid output
transformers. I hate them. I'll put them in the junk box for a later
date, maybe some kind of parafeed amp.

...the tomikos were what I planned to use
but to thin sounding... no bass with them. (saturate EXTREMELY EASY!!!
major disappointment, lesson learned)"


Of course these are nowhere near the cost of the Plitrons but...

His comment is not the first I have heard of this, I have heard the same comment on the Plitrons in both SE and PP.

One comment that I read about Toroid PP bass is that it is very,very clean which contributes to a somewhat leaner sound. Some may prefer this some not.

One guy figured that it was the Toroid Cores not being able to handle DC well on Single-Ended Plitrons Tranny that he didn't like the low end and I wonder how they deal with the issue of no air-gap. I have heard this can be a factor even with Toroid power-transformers, with some designers refusing to use them because of ocassional DC on the mains, I even measured my mains and found none with a simple test circuit that was published on line. But I like the Toroid for mains transformers no doubt because of the low DCR's.

Myself I have had an interest in R-Core outputs and maybe C-Cores as well. I'd probably spend a $1000 on a set of C-Cores blind but not Toriods unless I heard them.


As to the 28lb Hammond 1642SE's I'm using. They have been in production for nearly 10yrs now I believe. And I have had immense satisfaction with them. Further I was well pleased when I had some James SE outputs here to compare to and the upper bandwidth of the Hammond vs the James was indistinguishable IMO. While the Hammond's foundation in the bass and lower mids just squashed the James. Both tranny's reproduced about the same stage size width and depth wise. The Hammonds at $500 are a bargin IMO and could be used with a 300B as well. AKer jdg123 was here during the listening comparison and felt the same way with ultimately wanting to use these Hammonds with a 45 amp. I know that seems incredible for just a 2 watt amp, but when your looking for everything you can get with authority these Hammond 1642SE's do the trick. Certainly not all the Hammonds are like this but I do like these for sure.

BTW I would love to hear the Plitrons in a shoot out with the Hammond 1642SE's! :smoke:

You could even tell me I told so!:yes:

SET12
 
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dnewma04 said:
Good question about the O'netics, I know that Bud and many of his audiophile pals have moved away from SET to PP triode amps, so I'm not sure that he is even making SE transformers.
Click to expand...

Bud certainly makes SE transformers. His web page leaves an awful lot to be desired, but his business is primarily word of mouth and he's very well known within the industry. He has also done extensive consulting work for other companies.

The best way to find out is to just e-mail or call him, he'll even tell you if another product would suit you better than his...no kidding.

Disclaimer: Bud's a friend of mine, but he does excellent work in spite of that obvious handicap!
:D

Best Regards,
TerryO
 
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