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What s the best Class A integrated tube amp over 80W

I am using Sound Lab ESL speakers, which have a very high impedance at low frequency (30 ohms). At high frequency, SL speakers have very low impedance (3 ohms). I loved the class A in Pass Labs amp, but it took too long to FULLY warm up in my small room (9x11)-5-6 hours. I have a thread on Agon on this topic, but now I would like some recommendations on the best Class A tube integrated amp with >80W. Usually, integrated are the budget model of the line, but must be GREAT class A tube integrateds. Any recommendations?
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Showing 12 responses by chungjh

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chungjh OP
265 posts
 
@lowtubes.   That is what I was thinking. I am trying out an old CJ Premier 12. Just got Svetlana 6550 NOS tubes for it. Unfortunately, fuses on the bias pot for my ESL speakers went out. I will report back once I am set up again.
chungjh's avatar
chungjh OP
265 posts
 
Actually, SL speakers sound great once the amp is fully warmed up. 
chungjh's avatar
chungjh OP
265 posts
 
I have been considering VAC sigma 170i? Has anyone heard it?
chungjh's avatar
chungjh OP
265 posts
 
This is great. Thanks for all the responses. Keep them coming.
chungjh's avatar
chungjh OP
265 posts
 
91490 likes the LS 22-classic 150 combo. How about others? What preamp-older AMP combo do you like?
chungjh's avatar
chungjh OP
265 posts
 
I read that biasing VT100 tubes is a big headache. Why is it such a headache?
chungjh's avatar
chungjh OP
265 posts
 
I read that biasing VT100 tubes is a big headache. Why is it such a headache?
chungjh's avatar
chungjh OP
265 posts
 
What are some highish impedance tube amps? Regardless of Class.
chungjh's avatar
chungjh OP
265 posts
 
Here is what Ralph Karsten said about my situation.




11-09-2020 3:48pmThe Sound Labs are a different sort of beast. Like most ESLs, they don't work so well with amps that can double power as impedance is halved, since the Electrostatic principle doesn't rely on a driver in a box...

The impedance curve of the speaker varies by about 10:1 from the bass (peaks at 30 ohms) down to about 3 ohms at 20KHz. But the efficiency of the speaker is about the same though that entire range; for this reason most *but not all* solid state amps will tend to sound bright on them. A Brilliance control is provided to help tone this down a bit, as well as jumpers to allow for more bass, since all solid state amps struggle to make power in the bass region. This is why a tube amp of 140 watts can easily keep up with a solid state amp of 600 watts on that speaker!
Tube amps will stabilize much quicker than solid state (in terms of warming up to get where it needs to go to sound right), so with a good tube amp you should be having the system very near its ultimate warm-up in only an hour, and really sounding quite good in only 15-20 minutes. 
chungjh's avatar
chungjh OP
265 posts
 
I have talked to Ralph (AS) about this. SS output doubles with every doubling of impedance. Therefore my Pass Labs X250.8 SS amp produced about 60W at 30HZ with 30 ohm impedance. On top of that bass frequency takes more power to make the sound than treble. Therefore, Soundlabs sounds too bright at treble with most SS and sounds better with tubes which don't double output with halving of impedance.

I don't know why but I don't know anyone who uses an ARC amp with SL but many who use Atma Sphere amps.
chungjh's avatar
chungjh OP
265 posts
 
I have talked to Soundlabs and they don't have any specific preference, except for a lot of power. Soundlabs often plays Atma-S tube amp on shows. For SS, they have used JC-1's and others.
chungjh's avatar
chungjh OP
265 posts
 
Bruce

I agree with you. But, these speakers have an EQ dial for treble (as well as Mid and low) to adjust this attenuation/augmentation. There is no Sound Labs dealers near me, but I have been told that most use tube amps. There are no Atma-Sphere dealers around hear either, but one dealer has one on trade-in. I will try to see when it will be ready for demo.
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