Tube rolling suggestions for Unison Unico

I suggest you email Kevin Deal at Upscale Audio, I recently bought 3 different platinum pairs of 12AU7's for my Unico (I got the Mullards, the Radiotechniques, and the Siemens; I have yet to try them yet, I need to get speakers first to pair with the amp...) and he was very helpful in selecting them. Guessing from what he told me, you would like either the Mullards or the Siemens, but I would email him with what you're looking for and he'll point you in the right direction.

Hi Glitch,

Thanks. I have the Siemens from Upscale Audio, and they're not working out. That was the original problem. When I talked to Kevin, he said either the Mullards or the Radiotechniques would be good, but I don't want to choose randomly, and I'd really rather not throw down the capital for both.

What speakers are you thinking about? It really is a great amp.

I have done some searches on old threads on Audio Asylum where Mullards come up most often as the tubes of choice, a tad relaxed on top and glorious midrange. Similar to your experiences, I still have the Phillips stock tubes in my Unico, and simply haven't been able to convince myself to do tube rolling yet, as it just sounds so good. In my case I'm not sure I would want more relaxed top end... it is just right. I have visited Upscale Audio's website to explore... and really been thinking about the Siemens... interesting that they did not work out for you. How long did you leave them in, and did you leave the Unico turned on all the time? For me the difference in sound was nothing short of breath taking after about 36 hours on... and I haven't turned my Unico off ever since.

The best sound I've achieved with my Unico is with Brimar 13D5 tubes.

Hi Arni,

I left the Siemens pair in overnight, with the amp on, and listened the next day. So far, they've been very lifeless.

Is there something to be set for letting tubes settle in a piece of equipment for extended periods before passing judgement?

Hi Tvad,

By lifeless I mean one-dimensional, kind of flat, and "slow" sounding. I wouldn't say there's a lack of body, but perhaps we're describing the same characteristic in different words. The bass is also not as strong as with the stock Phillips.

My impression is that Mullards would be even more laid back in the mids than the Siemens. No?

Thanks for your input! I'll check those out.

Well, warming up overnight sounds appropriate, I think Tvad may have a point-maybe something is off with these particular tubes... although I would be hard to believe given that they are tested and all from Uscale Audio. But I think what you are looking for is probably the Mullards... given the description above...
Keep us posted on how this goes...
Good Luck

i use mullard cv4003s in my unico cd and tung sol blackglass in the unico amp. deep base and excelent mid, great for jazz.

i have noticed that many of the current tube designed preamps and cd players are not very tube sensitive.

i can't say the same for amplifiers.

older products are more tube sensitive.

In my unico I've tried several different tubes. In my system, my experiences are:
Radiotechnique: Beautiful airy treble - no bass at all
Mullards: Too Dark and syrupy for my 'modern' taste in music.. fantastic with pre-1970s music recorded on valve equipment though (loves my bossa nova collection!!)
Brimar 13D5: Better balanced than the Mullards I had..still the same house sound, but less so.. lots of missbass punch, high treble could use a bit more refinement
Siemens E88CC: Beautifully liquid, cyrstal clear, well balanced..perfect -EXCEPT they lack dynamics!!!
Amperex/Beckman 7316 Holland: So far, the best I've found.. Slightly drier than the siemens, but WAY more dynamic.. HUGE, precise soundstage (best of the lot), well balanced (perhaps just slightly tilted toward upper/mid, lower treble..but in a good way!).. not cheap though, but worth it!!