MC275 - McIntosh tubes vs. others

[McTwins]

Ov-Clove...

Thanks,
Ron-C

What is an Ov-Clove? :scratch2:

 

[Bill C]

Current KT88 tubes used by McIntosh are made by SED St. Petersburg and New Sensor. We use both suppliers.

Any tube by any vendor can fail. Usually this happens early in the tube's life. In the case of stock tubes they have a 90 day warranty.

The other day I changed outputs in my current 275 just for comparison sake. I tried NOS GEC KT88s, NOS Tungsol 6550, current Shuguang KT88s, Gold Lion reissues, and NOS Sylvania small bottle 6550s.

The Shuguang sounded closest to the GEC KT88s, Tungsols next pretty much tied with the Sylvanias then the GL reissues.

So I left the 6550 Sylvanias in and after about 30 minutes one arched over and blew the main fuse. It was clear which tube failed as you could see a burned spot on the anode-plate. GRRRRRRRR. I have more of these though so no bigee. It can happen with a small percentage of any tube brand.

That said, that is the first tube I have had arc in over 10 years of continuous MC275 use. It is silly to make a judgment on a few failyers about a whole tube brand. Out of a set of well regarded current premium priced KT88, I had to replace two out of the matched set of 4 I bought for low output.

So I tossed the bad Syl. 6550, replaced the fuse, reinstalled the Shuguangs and moved on.

That is life with tube amps.

Thanks,
Ron-C

Ron,

Which Shuguang KT88 were you referring to above?

 

[ron-c]

Ones I bought about 4 years ago.

Thanks,
Ron-C

 

[Bill C]

Ones I bought about 4 years ago.

Thanks,
Ron-C

Thank you Ron.

 

[jakeman]

Hi Jake, I wasn't aware that McIntosh supplied Svetlana KT88's as stock tubes. When did you get your 2102? Anyway, before I comment, I'd like to know what speakers and music you listen to.

As for the 220, I think TFK's are fine in the line preamp part. If you use the phono preamp, you might be happier with something else in that part.

I didn't think I was doing that much flag-waving ; but I do want to encourage people to take control of this wonderful hobby - that is, to the extent they want to refine their system. Plug and play is OK too, but if tube effects intrigue someone, they should get into it and not be intimidated. A minimum three-digit I.Q. will do just fine :yes:

Speaking of TFK, that was how this all started for me. A friend came over to see/hear my new amp and brought a pair of middle-aged TFK 12AX7's with him (wanted to compare them with my brand new factory Chinese 12AX7's) Well, minds and socks were blown off (just from those two substitutions!) Great sound can be a powerful drug :nono:

Nsgarch, I believe they used Svetlanas in 2006-07. Mine have the Wing'd C Svetlanas though I am told the Wing'd C 6550s are a better tube with the 2102s.

No you weren't doing that much flag-waving and your opinions make good reads even though they are a bit pedantic at times. :tresbon:

Anyway I've been running all 12ax7 and 12at7s Blackburn Mullards in the front eight . Last week I thought I'd put the stock tubes back in and I have to admit they sounded very good. Not as much air as the Mullards but the bass seemed more textured.

Have you had much time with the 2102 or has most of your tube rolling been with the 275s?

 

[nsgarch]

Nsgarch, I believe they used Svetlanas in 2006-07. Mine have the Wing'd C Svetlanas though I am told the Wing'd C 6550s are a better tube with the 2102s.

My only experiencewith 6550's was the SED Winged C's (16 of them!) in my ARC monoblocks. They sounded terrific, but that begs the question "compared to what?" and I don't have an answer, My only regret is that I never tried NOS blackplate Tung Sol 6550 which at the time could have been had relatively inexpensively, and according to some is the only 6550 worth the electricity :yes:

No you weren't doing that much flag-waving and your opinions make good reads even though they are a bit pedantic at times.

So you're saying I sound a bit "teachy"? That's possible, although I've never been described that way in person

I've been running all 12ax7 and 12at7s Blackburn Mullards in the front eight . Last week I thought I'd put the stock tubes back in and I have to admit they sounded very good. Not as much air as the Mullards but the bass seemed more textured.

I've tried the best Mullard NOS 12AX7's and CV4024's (12AT7's) and not been excited by them. They were OK sounding, definitey more detail, and quiet background, but not impressive sonically (to me anyway.)

Have you had much time with the 2102 or has most of your tube rolling been with the 275s?

I've spent no time with the MC2102, but have a lot of tube-rolling experience with the new MC275. Because both their circuit design, power supplies, and parts components are so similar, I would imagine the same tubes would give similar sonic results in either, everything else being the same.

 

[quinlanmw]

Nsgarch,

I had to refer to Webster's to confirm my understanding of the meaning of "pedantic". For what it's worth, I always learn something when I read your posts and hope you will continue to share your knowledge and experience of all things "tube".

There is no shortage of pedants around here, but you're not one of them. Your objectivity is refreshing. Keep up the good work.

Mike

 

[jakeman]

I've tried the best Mullard NOS 12AX7's and CV4024's (12AT7's) and not been excited by them. They were OK sounding, definitey more detail, and quiet background, but not impressive sonically (to me anyway.)I've spent no time with the MC2102, but have a lot of tube-rolling experience with the new MC275. Because both their circuit design, power supplies, and parts components are so similar, I would imagine the same tubes would give similar sonic results in either, everything else being the same.

The Mullards do sound different than the Telefunkens. To my ear the Mullards have more harmonics and air so voices and strings sound more natural and detailed. However the bass does not sound as tight compared to the TF tubes. Mids are lush with both. I suspect the TF 12ax7 are more linear with less harmonic distortion than the Mullards. I like them both which is why I switch them every few months.

 

[nsgarch]

The Mullards do sound different than the Telefunkens. To my ear the Mullards have more harmonics and air so voices and strings sound more natural and detailed. However the bass does not sound as tight compared to the TF tubes. Mids are lush with both. I suspect the TF 12ax7 are more linear with less harmonic distortion than the Mullards. I like them both which is why I switch them every few months.

Jakeman, FWIW, here is Steve Hoffman's take on the Telly v. Mully issue with the 275: http://audiokarma.org/forums/showpost.php?p=1103255&postcount=17
- Neil

 

[jakeman]

Thanks for the link Neil. Interesting opinion from Hoffman though he did wisely couch it as being system dependent.

12AT7's for McIntosh MC275

Mullards are leaner with more mids.

Teles are much bassier and slower.

System dependent thing. I am using Tele 12AX7's and Mullard 12AT7's right now in my MC275 Mark V. When I change speakers to a different brighter brand (that shall remain nameless), I switch to all Telefunkens and everything smooths out nicely but for normal speakers the full Telefunken sound is too slow and draggy with the 12AT7's in there.
__________________
http://www.stevehoffman.tv


On my system the bass is more prominent and quicker with the TF., Mids about the same and the highs more detailed and airy with the Mullards. Maybe its a mc2102 vs mc275 thing. More power and damping with the mc2102 is likely a factor.

My current system:

Pre-amp: McIntosh c220
Amplifier: McIntosh MC2102
Digital: MacMini, Weiss DAC2, NAD M5 SACD, Squeezebox Duet
Speakers: Verity Audio Sarastros
Speaker Cables: DIY biwired 16/4 inwall with Nakamichi connectors
Interconnects: Neutrik-Canare XLR, Blue Jeans Low Capacitance, Mantisory Special Twisted Cat5
Vinyl: VPI Scout with Soundsmith “The Voice” cartridge

 

[avstooge]

......And all for the cost ($400 on eBay) of a mint Hickok 6000A, which has paid for itself many times over and opened up a world of understanding for me.

Hey nsgarch,
Why did you pick a Hickok 6000A tester over a 600A model?
Just curious, thanks.

 

[nsgarch]

Hey nsgarch,
Why did you pick a Hickok 6000A tester over a 600A model?Just curious, thanks.

I didn't really choose one over the other. A lot had to do with peripheral factors like price, condition, availability, etc. If I had my druthers, I would have really liked to have a 539A (B, or C) but they were/are priced out of my budget, as are the very popular military TV-7/U testers which were (mostly) manufactured by Hickok. As for the 600A; it's an earlier model and as such may not be appropriate for the kind of tubes audiophiles would be using, and charts for setting it don't include many of those tubes either. Again, this is a good overview page: http://www.tubewizard.com/recommended_Hickok_testers.htm

- Neil

 

[midlife]

I bought a used MC275ce, it came with Sovtek 6550s, RCA 12at7s, and GE 5751s. It is very stable and sounds great. Nice mids, good bass, and requires only a very slight treble boost from the preamp tone controls. How much improvement could I really hear from some other tubes?

 

[ron-c]

The big advantage of the 539s is that we have a meter for everything which allows monitoring of the tube under test. In the case of KT88s by adjusting bias exactly to spec and maintaining test voltage while testing the tubes you can compare actual performance. This is the ONLY way to compare these tubes.
On the models with bias and 'english' knobs and one Mmho meter the same KT88s that tested above spec in the 539 will be all over the map.
The ultimate test for a power tubeis when in an amp while running power and distortion tests. What tube will make the most power in a current MC275? EH KT88s then a watt or two down SED KT88s. Both of these vendors supply McTubes. Of course the tubes shipped with your new MC amp are tested in the amp which must meet spec.

Thanks,
Ron-C

 

[SomeNoise]

Interesting enough, I have been blind testing my MC275V with neighborhoods, friends and family members who isn't audiophile or whatsoever. The test result is... 80+% can tell the sound was better when all original tubes were installed. They did not know what I did or what I've changed before the test. Of course, I myself also think the original tubes are the best sonically too. Most other tubes sound boxed and restricted (simple terms)

 

[Matt The Cat]

To each his/her own!

Getting those pesky small Chinese tubes out of my McAmp was the best thing I could have done for it.

-Matt

 

[Butchthetiger]

The Mullards do sound different than the Telefunkens. To my ear the Mullards have more harmonics and air so voices and strings sound more natural and detailed. However the bass does not sound as tight compared to the TF tubes. Mids are lush with both. I suspect the TF 12ax7 are more linear with less harmonic distortion than the Mullards. I like them both which is why I switch them every few months.

I use Mullard 12AT&/CV4024 tubes in my MC-275 and recently went from RCA JRC 5751 tubes to the new Full Music 12AX7 tubes from Grant Fidelity. The FM tubes are clearly lower in distortion, allowing one to hear more deeply into the music. They are the best 12AX7 tubes that I have used with my MC-275 amp. Would be interesting to try the Shuguang Treasure Series KT-88's and Full Music 12AX7's.

 

[nsgarch]

Butch, there are so many versions of the RCA 5751's. Are yours the triple-mica blackplates?

I like the CV4024's also (the old ones!) But the GEC A2900's are the best AT7 ever (as the current prices of up to $600/quad unfortunately reflect!!) I scooped up 3 quads when they were cheap, lucky me

And I have already compared the Shuggie Treasure KT88-Z's with my excellent NOS Gold Lions. Very impressive sound, the Shuggies, but according to my Chinese connections, they really need that 300-hour burn-in before they can be fairly evaluated, or even tested accurately (which is why the factory only matches them for plate current right after production!) I'm guessing it has something to do with the carbon coating incorporated in the new design.

I put 85 hours on them so far and they sound so great I wondered "Why 300 hours burn in?", but continued periodic testing reveals test numbers still getting better ;-) I mention this because it makes me question the validity of certain retailer "extra testing" performed before the tubes are fully burned in (for the full factory recommended 300 hours.)

 

[Butchthetiger]

Butch, there are so many versions of the RCA 5751's. Are yours the triple-mica blackplates?

I like the CV4024's also (the old ones!) But the GEC A2900's are the best AT7 ever (as the current prices of up to $600/quad unfortunately reflect!!) I scooped up 3 quads when they were cheap, lucky me

And I have already compared the Shuggie Treasure KT88-Z's with my excellent NOS Gold Lions. Very impressive sound, the Shuggies, but according to my Chinese connections, they really need that 300-hour burn-in before they can be fairly evaluated, or even tested accurately (which is why the factory only matches them for plate current right after production!) I'm guessing it has something to do with the carbon coating incorporated in the new design.

I put 85 hours on them so far and they sound so great I wondered "Why 300 hours burn in?", but continued periodic testing reveals test numbers still getting better ;-) I mention this because it makes me question the validity of certain retailer "extra testing" performed before the tubes are fully burned in (for the full factory recommended 300 hours.)

Neil, I don't know if they are triple mica-blackplate tubes. I do know that they were manufactured in 1953. I also have some RCA Command Series 5751's. Both are great tubes but the Full Music are IMHO better sounding.

I have Penta-Lab KT-88's and like them. Will appreciate hearing how your TS KT-88's perform at the 300 hour mark and if they are worth the difference in price.

Butch.

 

[Butchthetiger]

Butch, there are so many versions of the RCA 5751's. Are yours the triple-mica blackplates?

I like the CV4024's also (the old ones!) But the GEC A2900's are the best AT7 ever (as the current prices of up to $600/quad unfortunately reflect!!) I scooped up 3 quads when they were cheap, lucky me

And I have already compared the Shuggie Treasure KT88-Z's with my excellent NOS Gold Lions. Very impressive sound, the Shuggies, but according to my Chinese connections, they really need that 300-hour burn-in before they can be fairly evaluated, or even tested accurately (which is why the factory only matches them for plate current right after production!) I'm guessing it has something to do with the carbon coating incorporated in the new design.

I put 85 hours on them so far and they sound so great I wondered "Why 300 hours burn in?", but continued periodic testing reveals test numbers still getting better ;-) I mention this because it makes me question the validity of certain retailer "extra testing" performed before the tubes are fully burned in (for the full factory recommended 300 hours.)

Neil, I don't know if they are triple mica-blackplate tubes. I do know that they were manufactured in 1953. I also have some RCA Command Series 5751's. Both are great tubes but the Full Music are IMHO better sounding.

I have Penta-Lab KT-88's and like them. Will appreciate hearing how your TS KT-88's perform at the 300 hour mark and if they are worth the difference in price.

Butch.