[nurxhunter]

I have the RM9-mk2.  This may have ended (hah) my upgraditis.  I have a large tube collection to roll endless the PT and 6922.  Cannot say there is a 'best'.

Can someone recommend what caps I should upgrade the original from on the driver board, please.  Any other critical recommendations, please.

I think that the driver board caps are 22uF/450 axial caps (unless I am missing a decimal point).

If someone can recommend brand and values I can order and either me or my tech as an 'outpatient' can do a fast swap.

There is mild hum coming from right channel, less so on left; so, it's worthwhile for me to give this a try.

Any help greatly appreciated.  Much thanks.

[audiodoc]

The coupling caps are 0.22uf/450v.I have used Infinicaps signature series and my favorite Sonic Craft Platinum.Very clean,clear,less glare(not saying there is any to begin with)-- more natural sounding.Takes awhile for them to break-in.Well worth it.

Mike

[KDus]

You need to deal with the hum first. HIGH VOLTAGE...Inspect the big filter caps and 2 chokes. Look at all the solder connections and look for bulge-ing caps. The power supply of the MKii has more caps than the previous version and more that could need replacing.

[nurxhunter]

Thanks for reply--esp. to audiodoc--I did not see this until now.

I will have someone inspect the caps all around.

The front plate get VERY hot, and I thought that the caps on the driver board with that heat might be causing the hum--but--it seems more reasonable it should in in PS.

Roger has said the PS caps rarely (like never -2) have failed and the driver caps more--but also rare.

The hum is not bad -inaudible from listening position, only up close on VSA VR3.5.  I suppose with very efficient speakers it might be a problem, but who would use 125W/ch with HE speakers?

I feel the amp sound just a bit 'dark' (NOS DD EL34). The depth and width are great, mids PERFECT--if I could squeeze a bit more detail out, I might be cured.

With GL KT88, the detail is there, I loose the perfect warmth I like in mids, and upper mids are a tad sharp.

Would be nice to try some more reasonably priced caps.  I thought Auricaps are a pretty good deal; though they are also warm in mids and laking a touch transparency, based on my limited experience.

My goal is to pre-oder parts and have an 'in office procedure' locally done.

Seems I might have to leave in shop for inspection.  Sending by mail is so expensive, and I would need to get prosper carton, risk manhandling,...etc.

BTW--all tubes test NOs, perfect balance in quads with a variety of testers, and in the amp vis a vis current draw.  I use 34mA for EL34 and 40mA for KT88.  Still rolling the E88CC with great NOS types.  Thought to give caps a try.

Thanks all.