Martyn73

I called a valve supplier and the only explanation for cryo treated tubes sounding better was that they wouldn't sell them otherwise which is not a ringing endorsement. Taken at its highest, you may get a slight improvement but for £130 more than the cost of a normal service which would include the stock tubes which at least would keep the 006T within factory specification. I can't help thinking I would be happier with a solid state amp. The 727 is beyond my budget, but the 323S has to be better than a 252? Both the 252 and 323S are three stage I understand.

I'll have to sort out the source soon. Do you know of any custom made electrostatic energisers?

What's the ECC99? I tried searching but to no avail. I've found that decent tubes such as Cleartop or GE are difficult to get in the UK and wonder if in the long term servicing is going to be a problem. Hopefully, the 323S will be tolerable with vocals with the SR-404. Female vocals were irritating with the SR-407 and 323S and the combination of the SR-404 and 006T seem to reduce this problem. My torture track (which caused me to begin to hate my Sennheiser HD700), Slow by Kylie Minogue which is usually sibilant, is acceptable with the current Stax gear. Is it normal to hear a crackling noise in the left earspeaker when the 006T is cold, say a few minutes after turning on? Oddly, with an MP3 playing with the 006T set to zero I can still hear sound so this should be fixed on servicing.

Hi Spritzer, Thanks for replying. You probably saved me a lot of money! I've since read that the Kimik mod involves Philips 6CF7 tubes so I'll try to find a matched pair of RCA Clear Top tubes in the UK to replace the existing tubes. At least I can certify that the 006T has been serviced if I decide to sell it. The existing tubes seem to be working OK but I didn't notice harshness in OMD's Souvenir played through a HD 650 and a cheap Bravo Ocean tube amplifier. I'm starting to think that solid state may be easier and cheaper to live with. Does the SR-404 have a harsh mid-range with a 323S? I briefly owned a SR-407 with a 323S (both returned for various reasons) and I noticed that vocals could sound slightly harsh but this may have been due to listening to an MP3 of indifferent quality. Many thanks, Martyn

Hi, I recently bought a used SRM-006T to power my SR-404 headphones. The amplifier seems to be working fine and it has the stock 6CF7 tubes. Sometimes I notice slight distortion when listening to fast paced electro music and Souvenir by OMD. I'm not particularly attracted to the idea of tube rolling but I think I should get the SRM-006T serviced soon and I've been offered the Kimik upgrade for £200. This is a lot of money and I'm starting to consider getting a newer SRM-323S or 323II to replace the 006T. I'm not sure whether to service/upgrade the 006T or get a new and cheaper to run solid state 323. I did try SR-407s with a 323S and noticed that the mid range was harsh but the SR-404s are noticeably smoother so the amplifier may not the issue. I'd be grateful to read your views on the tube v. solid state debate as far as Stax is concerned. Having read many reviews on the 323 series there doesn't seem to be any negative comments but Innerfidelity weren't especially complimentary about the much more expensive 727II amplifier. I've chatted with a few engineers and aren't convinced about the merits of tube amplifiers for electrostatic headphones but honestly I don't really understand the technical explanations. Cheers, Martyn