ADA MicroTube power amps - worth it?

[Inazone]

Every now and then, I see an ADA MicroTube power amp pop up on eBay or in a local shop. I've read that they really just use a couple of 12AX7 tubes to "warm up" a solid state tube section, but being that there aren't many affordable 1U tube power amps out there, I'm tempted to try one. However, I've also heard that they have some reliability issues. Anyone own one of these?

[TomcatMF]

I have a Microtube 200. Its a great sounding power amp, and well worth the money IMO. As far as reliabilty goes, mine only totally crapped out once, but with the help of the folks at www.adadepot.com I was able to diagnose and repair the problem by replacing a $0.15 resistor. That's the only total failure I've had in the 7 years I've owned the thing. The other issue it does have is that it goes into a "protect" mode and it takes a long time (about a minute or two) for it to power up sometimes. Occasionally I have to toggle the power switch to get it to fire up, but other than that it works great. I like that I can carry everything I need on a 4 space rack.

[Elric]

I've had a Microtube 200 for about two years. I've been very happy with it. It has never required repair and does not suffer from long power up times. So far, I'd say they are very reliable given my experience to date.

 

And I've always thought all of the ADA stuff tends to *sound* really good. They did a good job with the hybrid tube setup, I suspect they may have lifted this from part of their ampulator circuit: it seems to help it sound and react more like a tube power amp, rather than just being a "mojo buffer" like some other hybrid amps do.

 

I love having a presence control on the power amp. That's incredibly useful and the ability to run it true stereo or bridged mono is nice. The 1U space is just great: small, lightweight, powerful.

 

The issue Tomcat refers to is a fairly common one where the power amp will take a while to start, and may be where you picked up the idea that they had reliability issues. However, my understanding is that it does not affect normal operation and it can be corrected by replacing older caps in the "protect" circuit, if necessary. I had heard about this and considered this as a potential issue when I bought it, but being an ADA fan, and having a certain amount of faith in their stuff and the support @ ADA depot helped me not worry too much about pulling the trigger on it.

 

Overall, I'm really glad I picked one up in the end.