Mastersound Compact 845 with Pvsane 845T


I own a Mastersound Compact 845 and Mastersound PH5 Pre Amp and orderd two Pvsane 845 T Valves.I was advised by the valve supplier that they would work ok as they were the top of 845 range of valves.I was then advised by my dealer that a mod had to be done to the Cathode Resistor on the Compact 845 to take account of the voltage increase.Otherwise the uit could in the future fail.Any body out there using the 845 T in the compact without modification to the resistor should be aware of this .Any comments welcome
patal
Hi Patal,
Glad you like the amp more now with the Pvsane T's. Did the tech need to mod the amp in anyway or did the tubes just drop in and need re-biasing?? I have some Psvane T's here now but haven't tried them yet. Still lovin' the 845A's at mo. If the T's are better then it will be seriously good,
Thanks for getting back to me,

Jonathan
Hi Jonathan,
He put in on test for over a day and done the required measurements and said there was no problem whatsoever.He did say there was a significant re biasing but there was still plenty of room up or down to spare. Re 845 Ts they sound very good still burning in, indicators say they can take 70 Hrs so using Isoteck burn in disc to help the process.
Hope this helps
Patal
The 845Ts have now been running for approximately forty hours and getting better all the time .Brightness and rough edges of high frequencies are slowly fading away .Soundstage is excellent .Vocals extremely clear and vibrant.No signs of amp overheating or valve problems.Will try these for a while give them a chance to settle down then try the 845B and determine the difference.
Regards
Patal
Another problem or perhaps not.The 845Ts have been running for approx 45 Hrs ,Sound is fine ,however there is a very very low buzz which does not effect the listening,coming from both speakers.This can only be heard when the music is off.the level of the buzz does not increase or decrease with the volume control.Could it be Bias or Hum adjustment which is required.ANY OTHER 845 COMPACT INTEGRATED OWNERS DOES THE LARGE CENTRE TRANSFORMER MAKE A AUDIBLE HUM/BUZZ.
Thanks
Patal
“…845-T is a drop-in replacement for 845A and 845B, but it is not a clear improvement over 845A, while 845B generally is….”
I can’t believe that someone having an amp of such a caliber could write this. The information is misleading and not true.
I’ll start from the beginning.
I’ve been using Mastersound 845 for three years, power tubes Shuguang 845B. I lost two of them in that period, one after 6 months and another one after two years (was plying 1200-1300 hours a year). After having done my homework I’ve decided to try Psvane 845T MkII. The difference between 845B and Psvane 845T is obvious, no need to do ABA listening tests, it’s obvious and instantly audible.
The thirst thing you notice immediately , Psvane is a cleaner sounding tube, less noise.
Psvane 845T MkII has much better HF extension and is a better resolving tube. You get better detail across the whole frequency range. There is more low level detail, soundstage has more “air”, more ambience info. Images are more precisely drawn within the soundstage, localization of instruments more stable. 845B images are a bit vague in comparison. Overall Psvane 845T has better clarity, better transparency and slightly improved dynamics.
If that’s not an improvement then what is?