KA1J
Member
I have two MC275 as monoblocks, a model V, & a VI. They're fed balanced from the C2600 and I've obtained some nice 60's 12AT7 to go with them. I've read as much as I could find regarding any caveats or benefits for selecting which socket is best to use with a perfectly matched tube (if it matters at all), if the rest of your tubes are not perfectly matched.
I found most of these tubes are reading in the 90's-104 (Minimum value is 50) on a TV7-DU but being in pairs, most have one triode stronger than the other side.
One of the articles I came across from 10 years ago related to balanced inputs, in the 275 MKV, it was claimed the 12AT7 in V1 is not in the audio chain. I have no idea, I discovered the small tube layout between V & VI are different, so advice based on one amp doesn't transfer to the other.
275MKV.....275MKVI
V1 AX7...... V1L AT7
V2 AX7...... V2L AT7
V3 AT7.......V3L AX7
V4 AT7.......V4L/R AX7
V5 AX7.......V5R AX7
V6 AT7.......V6R AT7
V7 AT7.......V7R AT7
What I'm hoping to do is find out if it makes any difference that I'll notice if I use a particular AT7 in any slot?
If for instance, as I've read in past searches, some contend there is one socket position with the 12AT7 chain that isn't part of amplification. If I'm only using balanced inputs, I'd rather put a lesser tube in that socket, not put time on a good tube, & keep it for future replacement.
Along with all that, is there a particular 12AT7 position that will greatly benefit from a closely matched pair? Or, should I just put them in and it doesn't matter how closely matched one 12AT7 is over another?
As this is Covid time & McIntosh is closed, I can't just ask them.
Thanks! & Stay safe.
I found most of these tubes are reading in the 90's-104 (Minimum value is 50) on a TV7-DU but being in pairs, most have one triode stronger than the other side.
One of the articles I came across from 10 years ago related to balanced inputs, in the 275 MKV, it was claimed the 12AT7 in V1 is not in the audio chain. I have no idea, I discovered the small tube layout between V & VI are different, so advice based on one amp doesn't transfer to the other.
275MKV.....275MKVI
V1 AX7...... V1L AT7
V2 AX7...... V2L AT7
V3 AT7.......V3L AX7
V4 AT7.......V4L/R AX7
V5 AX7.......V5R AX7
V6 AT7.......V6R AT7
V7 AT7.......V7R AT7
What I'm hoping to do is find out if it makes any difference that I'll notice if I use a particular AT7 in any slot?
If for instance, as I've read in past searches, some contend there is one socket position with the 12AT7 chain that isn't part of amplification. If I'm only using balanced inputs, I'd rather put a lesser tube in that socket, not put time on a good tube, & keep it for future replacement.
Along with all that, is there a particular 12AT7 position that will greatly benefit from a closely matched pair? Or, should I just put them in and it doesn't matter how closely matched one 12AT7 is over another?
As this is Covid time & McIntosh is closed, I can't just ask them.
Thanks! & Stay safe.
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