Help: low Maintenance Tube Amp short list.


I am making a short list of tube amps for audition. I would like to spend around 2000, give or take a couple hundred bucks. I would like to stay in the 50 to 60wpc range. And, last, but now least, I am looking for very low maintenance. I have seen some pictures of some tube amps, like the BAT models, with so many tubes that I wouldn't know what to do with them if they failed or needed replacement. Don't even ask me about biasing because I don't even know exactly what that is. Right now I have my eyes on a Conrad Johnson MV60. What else is there out there?

Help!
matchstikman
Biasing is not difficult, especially on amps such as the C-J which utilize a built-in metering system. If making this operation easy as possible is really an important criteria for you, you might decide to steer clear of amps that require the use of an outboard multimeter in order to set the bias, although this is not too much more of a hassle, and could eliminate some fine contenders. Also, an amp like the C-J, which allows separate biasing of each output tube, will not absolutely require that the output tubes be acquired in precisely matched sets only, which can make things easier and cheaper if you ever have to deal with one prematurely bad tube. For the lowest in maintainance of tube amps, you could narrow the field down to just those designs which feature auto-biasing, which never require any user bias adjustments be performed at all (there are designers who feel that fixed-biasing, where periodic adjustments will be necessary, has the potential to offer slightly better sonics, but there are also designers who successfully disagree and use auto-biasing on some very good amps). No other tubes on all-tube amplifiers besides the output tubes require such adjustments, so don't let the various smaller input and driver tubes scare you off - most stereo tube amps in the power range you are thinking of generally don't exceed 4 power tubes, so biasing them isn't an all-night affair. Also know that you probably won't have to rebias more than maybe once every 6 months or so.

(BTW, put simply and non-technically, setting the bias is how the correct operating parameters are maintained as intended for a particular circuit design and each output tube's type/brand/condition, because tubes, unlike transistors, will need periodic user replacement and will change as they age, and individual tubes always vary from one to another in their precise electrical characteristics. The actual adjustment of the bias current is most commonly done via labelled set-screws accessable through small holes in the chassis, in conjunction with built-in monitoring LED's or meters in the case of those amps not requiring the hook-up of a separately-bought outboard meter. The amp's instruction manual will guide you in the process and what the correct settings should read.)

As for what's out there, the answer is lots of stuff. I've owned the MV-60's predecessor, the MV-55, and it was a fine amp for the money, but there are many other brands competing in your range, including well-known marques like VTL and Audio Research. If I might ask, what is your system and room context, what do you listen to and how loudly, what is the solid-state amp you presently use, and what are you looking to gain by switching and why (or what inspired you to search in this direction)?
I highly recommend the Atma-sphere M-60 Mk2.2's (and so does T.A.S.)! Ralph's equipment is VERY stable, no output transformer (but you would want a speaker with around 8 ohm impedance or higher) and has the sweetness of tubes, with the bass punch of transistors. There are adjustments for bias, and DC off-set. On this amp, adjusting these settings is about as difficult as throwing the power switch on, and adjusting the volume knob on your pre-amp. Don't let these adjustments frighten you...they're real easy, only one for each set of tubes in the amp (some amps require 2 or more adjustments FOR EVERY TUBE!), and once set, they stay set for a long time!
The Bat amps are among the simplist to operate of all. The 4 main power tubes (the big ones) are on a auto bais circuit. Plug and play. a green led tells you everything is ok. The other tubes do not require adjustment.

About the only thing you'll need to do is if a tube goes bad, which happens about every 1 or 2 years for me, isolate it and replace it. By bad, you'll hear static, rushing water noise, popping, etc. Just slowly change (with powered OFF) tubes from one channel to anouther until the offending noise swaps channels. That's the bad tube.

This is one easy amp to operate. Don't miss out on one the best amps around.
The EAR 534 has no bias adjustments to make and is 50 wpc. Go to the website of EAR and check it out . It retails for 3595 and up. I do own one and have it for sale now for 1900 shipped to you in an ad on Audiogon. Mine has balanced and rca ins/outs and gain controls for each channel. It can be in a mono mode or stereo. I recently went SS in my amp areas because of ventilation problems in my new cabinet area after the move. I am by no means saying it is the only choice available but it made my Quad 989's sound extremely good.