Preamp Deal of the Century

Amandarae,

No, no step up transformer involved. I emailed Mick about my specific cartridge and he said no problem using it as that's the same cartridge he uses. It does sound like an overloaded phono stage to my ears. No difference between channels either. I'll try to explain in slightly different words what's going on. It sounds okay from initial play until the unit warms up for about 45 minutes. Then the sibilance sets in and gets worse, pretty quickly (5 minutes or so), until the sibilance is so pronounced it effects everything which sounds like distortion to me.

Hi Patrick. Yes, sounds like a classic case of phono overload to me too. Are both Syrah's using the same tube topology in the phono stage. Some used a combo of the 6j5 and 417a/5842 and others with a 6dj8/6j6. Are there any gain options on them ei: high and low. You mentioned you are using a high output mc... what is the manufacturers loading recommendation?

Don't think I'm not anxious to answer these questions and get some input but I've got a really busy day going. Company is arriving today for a weeks stay. I don't have the tube layout memorized. Maybe Steve will post about the two preamps and their minor differences. One point to consider is that in the other system with a 901 cartridge it sounded bad too. In both systems and with both cartridges it had, at one time, sounded as wonderful as this thread talks about. Anyway, the factory loading spec for my cartridge is 47K. Again, this cartridge (same one I have) is one that Mick uses.

Hi, Ecclectique, both amps use the 417a/6GK5 or 6FQ5 tubes. I am pretty sure it is not the phono stage that is causing the problem. The first amp went bad in the line stage functions too. It acted the same for the phono as well as the pre amp functions.
Having two Syrahs with the same problem would make me think it is something we did or another problem with both of our systems. We have spent a lot of time ruling that out.
Remember, the first Syrah sounded wonderful in both systems, and for over a year.
Thanks for your time and responses.

Hello Vetterone. Thanks for the prompt reply.Due to this abberation being common to both units and through both the phono stage and the line, I think it would probably be the most logical to start with the rectifier and regulators in the power supply. A weak rectifier or mismatched halfs of a full wave rectifier can have a profound effect on both the line and phono and can indeed demonstrate the characteristics that Patrick is alluding to. Can you test your rectifiers and tell me what rectifier you are using [5ar4, 5z4,5u4,5v4?? etc]as well as regulation tubes. Do you have any spare rectifiers around you can substitute? The regulation tubes are not likley the culprit here unless they are very weak or grossly mismatched as they do not have much influence on the tone per sey,but... rather more with spacial cues and air in the soundscape. Are you experiencing any woofer pumping in the phono stage? Try turning up the gain in the phono "Without" cueing the record and observe the reaction of the woofers. Is it a thinness that may be highlighting the upper midrange/treble range? Sorry to ask so many questions here sir, but persevere here and I am sure we can get to the bottom of it in time for Lugnut to entertain his guests. cheers David