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In Reply to: RE: Considering A Change In Electronics? Any Recommendations? posted by RGA on May 02, 2022 at 20:42:25
It has been awhile since I have had the F7 hooked up to the JBL, and it takes that amplifier a good week to settle in. It finally turned the corner last night, and is sounding nice on the JBL. This is a 35 wpc push pull from Nelson, and it is enough power to hit the volume levels I need with the JBL. It is not a Class A amplifier, but nevertheless quite nice for SS. Makes me think that Class A SS is not a bad choice either.
One higher output SET amplifier I have always been curious about is NAT Audio. You do see them on the pre-owned market once in a while in the US. The other viable option are the big Cary amps based on the 805 or 211 tubes. Line Magnetic seems like another option. I don't know that I can find a Kondo based amp on the used market that I can afford. I am adverse to buying from Audio Note of the UK based on what happened with the company and its relationship with Audio Note of Japan. Perhaps my understanding of the situation is incomplete, but I have a hard time supporting them.
Ever listen to the NAT stuff?
Follow Ups:
There are two sides to the story regarding AN UK and Kondo. I have read both sides - I side with Peter's (AN UK's) case and subsequent interviews.
What surprised me was that it was AN UK that wanted to pursue SET amplifiers while Kondo was pushing 2a3. Peter's reply on this matter was made to this forum over 20 years ago (linked).
But there are other companies as you note from Line Magnetic and NAT and I would add Melody Valve Audio which seems quite underrated to me. And of course, as you note Kondo amps are still available.
I have not been a fan of Threshold or Pass Labs - I prefer First Watt but then if I am going to take a lower-powered First Watt SIT amp that is a "SET-Like" sound I'd rather just get a real SET amp. The latter has the ability to tube roll.
Edits: 05/03/22 05/03/22
This is a 35 wpc push pull from Nelson, and it is enough power to hit the volume levels I need with the JBL. It is not a Class A amplifier, but nevertheless quite nice for SS.
It is a Class A amp. And rated output is 20 watts into 8 ohms and 30 into 4 ohms. Ever read the manual ?
"The F7, a nice little Class A amplifier with hardly any feedback does not have the brute force advantage. It resorts to a stratagem that makes the dance a little more like a Tango."
This is from the First Watt website."The F7 is a very unique power amplifier, a two-stage push-pull JFET/MOSFET
topology with fewer parts than any First Watt amplifier to date and incorporating
a very interesting balance of very low negative voltage feedback and a little bit of
positive current feedback to give an astonishing measure of control over reactive
loudspeaker loads."
There are different implementtions of Class A. I typically think of it as having the output transistors amplify the whole waveform and never turning off.
This is a push pull amplifier, so the transistor is not amplifying the whole wave form. Now the transistor may stay on during the entire waveform and not amplify the signal and can still be considered Class A. But it not what I typically think of a Class A amp....and to me the F7 is a push pull amp and not what fits the definition of Class A
"The Class A amplifier is the simplest form of power amplifier that uses a single switching transistor in the standard common emitter circuit configuration as seen previously to produce an inverted output. The transistor is always biased "ON" so that it conducts during one complete cycle of the input signal waveform producing minimum distortion and maximum amplitude of the output signal."
The F7 does not meet this criteria since it does not conduct one complete cycle of the waveform.
Edits: 05/03/22
does Nelson (who writes all the manuals) say not once but *twice* (did you actually read the manual?) that it is? BTW, just click the embedded link I provided to read it.
Here's his second quote in the manual:
"Conclusion
In case you haven't noticed, I enjoy amplifiers with some personality. They don't have to measure perfect, they just have to sound good. This is a very simple little Class A amplifier with lots of personality, and I hope you enjoy it as I do.
Nelson Pass
12/5/16"
Sheesh!
I am not going to sit here and argue whether the amp is Class A or not. I have the manual and the box in my living room. Yes I have read it. I have talked with Nelson about the amp specifically. It is a Push Pull amp, and it is biased in Class A. But it is not a traditional Class A amp where the transistors amplify the whole waveform. That is a fact. Now you can debate semantics if you want, but it won't be with me.
I am not going to sit here and argue whether the amp is Class A or not.
I'm sure Nelson Pass would have a big grin on his face as you tell him he doesn't know what class A operation is. ;)
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