who makes auto biasing tube amps w/200 wpc

Let's simplify the matter.

I'm at a real loss here to think of tube amp makers whose amps are both auto bias and have good power, say around 200 wpc or more @ 8ohms?

Might could go as low as 150-175 but I feel 200 @ 8 is about right, and would like to get as close to that spot as possible.

BTW... Non bridged amps.

Many thanks
VTL, BAT (150 wpc)
I don't think VTLs are auto-biased. Having an auto-bias is a great advantage for longer tube life so it's important! BAT is being converted to mono by reconnecting other channel tubes to the one channel path giving 4 tubes per channel as mono version(mentioned by Tom Hankins) Mono version is VK150 and it's pricey new or used. Otherwise a great contender to your consideration with very good built quality.

What is your budget?

How savvy you are with troubleshooting? Most of powerful tube amps are not user friendly, burn tubes fast and require some technical knowlege or if not, sending it to service provider would run into tripple digits just for shipping.

Do you have money-no-option situation?

What speakers do you have?
Check the Rogue Zeus,I am not sure if it's auto biasing,I guess not but I haven't adjusted mine in a long while. 200w pr channel.Real heavy big amp.

the Atma-Sphere MA-2 is autobias.
McIntosh MC2301 300w mono block
The series II and III VTLs are auto biased.
Wolcott P220 monos. (not shure if they are still made?)


Nope... money is an issue so I'm unable to invest heavily.

Speakers, currently are Silverline Sonata IIIs which I have posted for sale actually. I do have others though. Though, none as good as the IIIs.

They feel like 92 db speakers running at 6 ohms or so, nominally. A BAT vk60 ran them very well to quite remarkable sound levels.

They responnd best to amps with good power supplies. My preff is tubes normally... but The Sonata IIIs don't seem to mind what topology the amp possesses. So long as it's a decent amp or above.

I simply want to get different color speakers and perhaps trade up there too.

So $2K $3K approx. is about the whole budget for amp (s).
Thanks for the Audio Valve note, Bill. Nice amps, but a Wee bit out of the budget. I would actually prefer a Hybrid amp that allows tube rolling in the 200wpc or better area.

Running kt88's in a audiovalve Challanger 180 monoblocks will give you 180 watts (auto bias,can run el34,6550 and kt88's).
Some Berning amps are an option. BA-150 is an old amp that puts out about 200 wpc. It was also made by Audionics. This was in the late 70's. These can be had for about 800. New Berning Quadrature is 30K but meets your requirements. Mike

OK... here's a thought... who distributes and/or seells the Audio Valve Challenger amps?
Blindjim I think audiofeil in Clarence NY carries the line;as I have seen ads from him on Audiogon selling the product.
I bought mine on audiogon used last year;it has been a great amp driving a very tough load (soundlab m2's) and it autobias's as the op was inquiring about;there might be other sellers but audiofeil is the only one I can think of.


where does it rate in your opinion amongst other tube amps your've heard? Please note those other amps?

One pr of mono blocks is up for sale now... but beyond my reach currently. going that route I've save up... a fair amount more.

Why do you need 200wpc when your speakers are 93db?

Just curious.
The difference between 200 watts and 100 watts is 3db.....not a lot....call it 150? I don't know how to do logs, but it is sure to be almost unhearable.

Autobias? terrific idea! Why didn't I think of that?

93db speakers MAY be able to use 200 watts if they are in a pretty good sized space and pushed. Running them at say......30 watts continuous with 9db amp headroom? Somebody do the math on that.
The other possible reason is large phase angle loading. In that case, I'd probably want to rethink tubes...
Blindjim I have had 4 tube amps;vtl 225 monoblocks,manley ref 440/200 monoblocks,cary slam 100 mono's and the audiovalve's I currently have.
The vtl and manleys sounded very similiar and they were driving merlin 4b+'s and dunlavy sc3's;controlled bass,midrange that most tube lovers crave and extended highs,the manleys ran 6550c's and the vtl's ran kt88's.
The cary slam 100's are the ones I had the longest;running jjkt88's at 95watts triode;these amps were the best I have owed until now;these amps drove the dunlavy's and the sound was just fantastic and then I got the itch to see what electrostatics were all about and found the cary's to do a very good job but were being taxed and it was noticable;loss of bass control on the panel,the midrange fell apart and the overall sound was degraded;these amps were the first generation on the slam 100's and it was fixed at triode with no ultralinear switch as the newer models had.I traded them in on the audiovalve challangers and have never been happier.Sound is first rate from top to bottom,they seem to control the panels with ease.Build quality is excellant and I have not experienced any problems with these amps since I aquired them.
I have not tried tube rolling on them as I am rookie in this area but have made some inquiries on where to start and what to try.


All of that is quite encouraging. Thank you.
Moscode 401HR. 200 wpc + auto biasing. I'm sure you can get one used in your price range.


thanks ... I had thought about the Moscode initially but wasn't sure... and I like the idea of a hybrid too as those I've heard seem to do better in the bass region than strickly tube amps do.
I've been heavily considering it as well (the 402au is also on my short list). Keep us up-to-date on where you come out, as I have a similar interest in upgrading from my current gear.
Space Tech Labs.Hand crafted in Vancouver.Hybrid ss/tube with auto bias.I own one,it rocks.Flip me a pm if you are interested in technical particulars.
....on the Moscode front, there's but a slim chance of me landing one.. 401 or 402. Consequently as I'd be lurking on the preowned pages for one. They aren't often visiting thsoe pages either.

The D class amps interest me still. With my speakers a good set of Class D monos ought to be a nice fit. they'll coast on my current speakers but will enable me to be a lot more flexible in making future speaker matches.