|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
71.137.237.5
In Reply to: another approach posted by DaveV on November 30, 2006 at 21:00:08:
DaveV,I believe I'll be doing the capacitors as well as the tubes. My MR67 has a problem in which I think the two tubes on the MPX decoder- 12AU7 and 6U8, are being driven too hard. These tubes appreared to be new when I bought it and soon developed burn spots in the flashing. Resistor, capacitor- RF emspitzeratoriser- who knows?
As the signal meter is sticky, no alignment for no one knows how many decades, mostly original tubes, the hot running MPX tubes, I'm planning a whole going through with caps, resistors, alignment, and all new tubes. This all may make this close to a $900 tuner, but after 20 years use with the inflation in McIntosh tube tuners, I anticipate the value around $901 and I'll have used the thing for free!
I find the sound of the MR67 to be just fantastic- nearly unbeatable FM- if reception is solid enough. I'm convinced the MR67 bests the MR71 sonically- I don't know why. With luck, this tuner will last the rest of my life- or at least until the end of analogue broadcasts in 2009.
BTW, What do/did you use for the 6U8 in your MR67? Modaferri suggests to use the ("higher gain") 6GH8A and I've also read that the 6BL8 is the thing. If the 6BL8 is best, I have an odd-out Amperex PQ 7643 (E80CF or 6BL8). I'm curious as to the relationship of the 6BL8 to 6U8- interchangeable? Also, I bought some Amperex (Philips, France) 6GH8As and these appear to be identical to the original "McIntosh by Amperex ECF80's- 6BL8s which are also Philips, France. For 6U8, I have these attractive Sylvania Gold Brand "GB-1252"/6U8As plus a couple of 6678s. So, 6U8 or 6GH8A or 6BL8 ?
Thanks!
Cheers,
Follow Ups:
To be honest I haven't used my MR67 in years because I found it difficult to find broadcasts that sounded good enough for me to want to sit down and listen to. Had I roof mounted my NOS Finco FM-4G antenna maybe it would have been different? Now that I'm out of the NY Metro area there's even less reason to listen to FM because the station choices in my area of SC are grim in my opinion. My FM experience now is with a Pioneer Receiver that serves only as background music when I'm puttering around the house. I stuck with the tube numbers marked on the MR67 chassis and never tried alternates. The MR67 is a good tuner but I thought my Citation lllX sounded better. My MR sounds too full for my taste, like too much bass overlay where the lllX has a brighter more open sound. Could be the different de-emphasis circuits in play but because FM broadcasts have gone downhill so much over what they were 30 years ago I gave up on trying to have FM sound I can really enjoy and all my efforts go to the enjoyment of LP's. I was never fully up on the interchangeability of 6U8, 6BL8, 6EA8 and 6GH8. I went thru that with a couple of Scott integrateds I have and I never reached a conclusion.
Seems that Scott was good at changing the tube numbers in different production runs of the same model. Maybe it was a price and availablity thing with them?
This post is made possible by the generous support of people like you and our sponsors: