Quicksilver audio silver 88 mono amps

@fjs1155

"I replaced the JJ KT88s with Tung Sol KT120s and the difference was remarkable."

fjs1155,
If you can recall, did you find the stock JJ KT88 output tubes to sound kinda lean and edgy and less musical in your QS KT88 Monos?

Asking for a friend who’s not yet researched replacing them with something like Genelex Gold Lyon KT77s or GL KT88s, or PSVANE CV-181-Ts, or Shuguang Black Treasure tubes. Thinking this might help... wondering if you tried any of these with your Mono 88s in addition to your current Tung Sol KT120s.

@ gochurchgo: I will receive a pair of new Quicksilver 60 Watt monoblocks next week.  I intend to pair it with a Thor TA-1000 preamp with significant upgrades including about a dozen Vcaps.  The other preamp I have is nearly as good, but it's homemade, unfused and based on subminiature tubes so I don't know how helpful that is.  Come to think of it, the Thor is completely obscure, too - but interesting!  :o)

After reading for a couple of hours, I have ordered a matched quad of Psvane Black Treasure KT88-T Mark II to try as an initial upgrade to the stock Chinese tubes.  Other contenders may include the Tube Store Preferred Series ($280 per quad) or Sophia Electric KT88-ST (blue coke bottle, BUT starting at $500 per quad!).  JJ KT88 are also available for about $175/quad but I'm not sure they are at the same level; Merlin VSM speakers will reveal as much detail as they can get.  The VERY low end is handled by a JL Audio Fathom sub.

Any suggestions on the best KT88 to run in a straightforward pentode amp running some very neutral and musical sounding Merlin VSM floorstanding monitors?  Very slight tendency to brightness, with the wrong things upstream, but mostly to honesty (no gripes after 13 years with the same speakers!).

Hi @augwest  I have the Quicksilver 60 Watt monoblocks and to deal with some brightness, and on the suggestion of @decooney (here), I went with the Genelex Gold Lyon KT77s. I've been happy with them. At this point, I'm pretty sure that my low ceiling is the main cause of the brightness (I've put nice tubes in other sockets, too, so it's not them), but my sense was the the 77s helped. FWIW, I have a QS Line Stage preamp with good NOS tubes in it, too, and an R2R DAC.

@augwest
The QS mono tube amps paired with your recapped Thor tube preamp should be fun. Appears VCap was a common upgrade in your preamp, photo here, and nice wide and thick copper strips on the main board, cool.  :) https://www.audioasylumtrader.com/images/y2013/12/100421/FullBoard.jpg

IF it’s a new set of QS monos, give them and internal caps time to burn in with stock tubes or the PSVANE if you get them soon enough. The PSVane BT Mark Its should sound pretty smooth, just helped a friend put them in an integrated amp. After the input tubes burn in on the QS amps, (if new stock tubes) you may want to update those and store the stock ones away. Also, kinda depends on your preamp and tubes too and how bright or smooth they are. It’s a basic balancing act on both ends. Is that brand new or used (burned-in) monos and what input/signal and output tubes are in them now?

@decooney - Yeah, that heavily modified Thor TA-1000 is a special preamp, with a sound I would describe as detailed and authoritative, and neither bright nor dark. Its separate power supply probably weighs more than most components I’ve owned, but I could care less about the form factor.

These are NEW QS 60s received from the factory TODAY with all stock tubes, all brand new. Psvanes have yet to arrive.

One odd thing is that while both the website and owner’s manual reference an LED for setting the bias, there most assuredly is no such thing on my amps! Instead there are ports for voltmeter probes (regular ones, not the 1/4" jacks on the old QS amps).

Since the manual provides no actual numbers, I don’t know what bias current to target. They both ramped up to 70 mA after I installed the factory tubes so I figure that must be close - I’ll call the factory tomorrow. Does anyone here know the actual factory recommendation for THIS current-gen. Quicksilver "60 Watt" mono amp (there have been various QS KT88 amps over the years)? I don’t care about the LED indicator; as an Electrical Engineer and irrepressible tinkerer I would rather use a meter anyway.