MC275 - McIntosh tubes vs. others

Major thanks, my fingers are still twitching, physically, and metaphorically. :rockon::beerchug: :bowdown:
I will take an opposite view. I took one of my preamps in for servicing. The McIntosh tech said I should change out the phono tubes. He said that he often finds that these McIntosh branded tubes are too noisy for the phono application. I wasn't using the Mac preamp for phono but I changed them nonetheless. Again, do as you see fit.
 
I will take an opposite view. I took one of my preamps in for servicing. The McIntosh tech said I should change out the phono tubes. He said that he often finds that these McIntosh branded tubes are too noisy for the phono application. I wasn't using the Mac preamp for phono but I changed them nonetheless. Again, do as you see fit.

Man, no easy paths! Did you upgrade the tubes when you changed them out? And if you don't mind, what tubes did you go with?
 
Man, no easy paths! Did you upgrade the tubes when you changed them out? And if you don't mind, what tubes did you go with?
I changed the tubes to using Genalex. They have gotten good reviews in general and are relatively affordable. If you have the cash and want to step up, I suggest looking at tubes from Upscale Audio or someplace like Tube Depot or Tube Store.
 
Well, I`ve read this post with great interest, being I have (4) 275VI`s configured each in mono with balanced inputs used.
They have been in use as my highs(1,700 Hz~20khz.+. and mids (80 Hz~1,700 Hz since 2012 in a tri-amplified Mac XRT-30 speaker system with probably around well over 1000 hrs. of time on them and have not given me any problem at all.

The system is run every weekend(Sat.& Sun.)evening for either a DVD movie or CD music, and when my next door neighbor BIL goes on vacation for a week(5 X a year), then the system is run every night for 7 evenings of 4 or more hrs. per session..

The 275`s each sit on a it`s own cutting board(sorry about that, but they were quick and cheap !) on the well padded and carpeted floor below the XRT-30`s matching center channel speaker.

I realize that these 275`s are not being asked to swing large amounts of power and being in mono helps spread the load(current) amongst all 4 KT88 in each amp, however they can & do get driven hard since the XRT-30`s are not very efficient and I do like to play the system at very realistic SPLs when I fire it up..

Plus I think since they are running on the floor which is the lowest temperature for them, with some vibration isolation provided by the carpet/padding that has helped the longevity of the original KT88`s..

Next time I pull the cages for dusting, I`m going to setup my Amplitrex A 1000 tube tester on the kitchen table and take a gander of each KT88`s one at time to see how their aging, since I didn`t install an hr. meter on the fat power cable that AC mains feeds the 275`s at the time of installation.
But when I end up replacing the KT88`s(a very, very expensive proposition that I`m not looking forward too !!) I will possibly connect an hr. meter to that AC line.

Anyway, just my experience & $.02`s worth folks.

Kind regards, OKB
 
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BTW, I've left my MC 275's tubes naked and afraid. Besides safety "issues", are there any reasons not to leave them open, such as dust buildup (assuming that time goes by without a good dusting)..... THX
 
BTW, I've left my MC 275's tubes naked and afraid. Besides safety "issues", are there any reasons not to leave them open, such as dust buildup (assuming that time goes by without a good dusting)..... THX

No, nothing wrong with keeping naked, as long as you use them in an controlled environment..
People, pets, ect. can harm themselves and the tubes.

The tubes will probably run slightly cooler..

My BIL had a large St. Bernard who used to join us in my living room when watching a DVD, and large hound dog type dogs can drool sometimes, and with the shaking their heads for whatever reason, can sling substantial slobber wads in great arc`s across the room and I had visions of one of her "sling-nasty`s" landing on one or more of my 4 floor residing 275`s and popping one or more of the (16) KT88`s that would die like a trouble shooting/automobile repair lamp while working on a car underneath, with that one little drop of liquid that lands on the incandescent bulb !! Pow !! At nearly 63, I`ve seen it happen more than once, whilst helping friends work on the cars in low light..

So I keep my cages on, even after she passed on...

But who knows I might have a violent juicy sneeze and inadvertently shoot a expensive snot rocket into one or more of the amps eight feet, or so, in front of the listening seating distance..

Hey !! It could happen ?? HA !! I hope not !! :no:

Folks can do as they feel comfortable with their wallet..

Kind regards, OKB
 
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No, nothing wrong with keeping naked, as long as you use them in an controlled environment..
People, pets, ect. can harm themselves and the tubes.

The tubes will probably run slightly cooler..

My BIL had a large St. Bernard who used to join us in my living room when watching a DVD, and large hound dog type dogs can drool sometimes, and with the shaking their heads for whatever reason, can sling substantial slobber wads in great arc`s across the room and I had visions of one of her "sling-nasty`s" landing on one or more of my 4 floor residing 275`s and popping one or more of the (16) KT88`s that would die like a trouble shooting/automobile repair lamp while working on a car underneath, with that one little drop of liquid that lands on the incandescent bulb !! Pow !! At nearly 63, I`ve seen it happen more than once, whilst helping friends work on the cars in low light..

So I keep my cages on, even after she passed on...

But who knows I might have a violent juicy sneeze and inadvertently shoot a expensive snot rocket into one or more of the amps eight feet, or so, in front of the listening seating distance..

Hey !! It could happen ?? HA !! I hope not !! :no:

Folks can do as they feel comfortable with their wallet..

Kind regards, OKB

LOL! I'm afraid that my snot rocket would set up an arc searing my sinuses like bacon. Well, the ER crew would get a great laugh. :beatnik:
 

I run a MC275CE together with a C22CE.

For sure, the McIntosh labelled tubes did not survive the time. So, here are my replacements.

MC275 CE
Gold Lion KT88, RSD E83CC, JAN 12AX7WA Philips :thumbsup:, Westinghouse 12AZ7A

C22 CE
Philips E83CC SQ :bowdown:, JAN 5751 Sylvania, Brimar 6060:bowdown:

Unhappy with
Sovtek 12AX7LPS:rolleyes:, JJ ECC83MG :eek:

Not in use for the moment
JJ KT88, TAD KT88-STR, Siemens E81CC :thumbsup:, Siemens ECC801S :thumbsup:, Mullard CV4024, Mullard 12AX7WA :thumbsup:

IMHO the most important stage, building up the sound, is the preamp.
Therefore do not be stingy with the money you spend on the tubes for your preamp.
 
hi, i have 275V with kt88 svetlanas (round holes) , and i see many pictures V comes with "Square" holes ? last production they used new tubes ? ?


mcintosh-kt88-vacuum-tubes-kt-88_1_a3b7a0a1631a552c87be4a75ea5b3b29.jpg
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Mac tubes were checked in a Power amp to make sure they met specs, while Davie Obrien was alive. thru production of the MKiV version I was told. For the prices they charge now I assume they are doing the same and the rejection rate must be pretty high causing them to increase the prices. Checking a tube on a tube checker doesn't tell you anything about the actual audio performance of the tubes. Plus they must be matching them for gain and other parameters, too. ARC checks all their tubes. too. This is the issues with tubes, if you can't afford to put the best tires on your Ferrari you should buy an American SUV. That's one of the main reasons I gave up tubes in the 70's. Davie was having. very difficult time finding enough tubes for new units let alone owners units and we weren't talking to the the Soviets back then..
 
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