MC275 tube rolling with mixed tubes

[arien]

Hi Arien,

Thank you for your reply! Mine is MKIV Gold version. I envy the monitoring circuit that the latest version has. I will get the fuse tomorrow or on Saturday so will check with my healthy Reissue GL tubes if there is no damage to the amp. Then need to test the malfunction tube of Psvane. I will update here once I have any news on the issue!

Hi kj510,

Hope everything's okay...

Just a question, why do you have to test the tubes, why not send it back to your dealer and let them test it, the thing is that if you happen to plug the faulty tube then it might blow your fuse again and who knows what other damage it might cause, just an opinion...

 

[kj510]

Hi kj510,

Hope everything's okay...

Just a question, why do you have to test the tubes, why not send it back to your dealer and let them test it, the thing is that if you happen to plug the faulty tube then it might blow your fuse again and who knows what other damage it might cause, just an opinion...

I purchased directly from Psvane web site and sent directly from China. Grant Fidelity is an US or Canadian company and asking me to check the wrong tube(s). You know that's their service level they can offer. Of course if I bought from a dealer in Japan, I would complain if they ask me to check brand-new tube for them. I need to accept the risk of buying from oversea. I just think it would be a good information for people in the forum in the future what service level is expected from them. In fact I purchased Grade A.

I think Grant Fidelity wants me to send back only the damaged tube, that's why asking me that. But if they ask it, I will ask them to make sure it matches the lest. Anyway, I will share their after service with you as it would be a very good information for who are thinking to purchase Psvane in the future.

 

[arien]

I purchased directly from Psvane web site and sent directly from China. Grant Fidelity is an US or Canadian company and asking me to check the wrong tube(s). You know that's their service level they can offer. Of course if I bought from a dealer in Japan, I would complain if they ask me to check brand-new tube for them. I need to accept the risk of buying from oversea. I just think it would be a good information for people in the forum in the future what service level is expected from them. In fact I purchased Grade A.

I think Grant Fidelity wants me to send back only the damaged tube, that's why asking me that. But if they ask it, I will ask them to make sure it matches the lest. Anyway, I will share their after service with you as it would be a very good information for who are thinking to purchase Psvane in the future.

Now i understand, thanks kj510, hope everything will be sorted soon and you can start enjoying music in your system....

 

[kj510]

Test did not identify but 4 Psvane blew fuse again immediately

Now i understand, thanks kj510, hope everything will be sorted soon and you can start enjoying music in your system....

Thank you!:thmbsp: I received spare fuses today and tested as Rachel advised using 3 good tube I own and one of 4 KT88-T each in MC275. This test did not blew the fuse. I thought the tubes might be ok and tried 4 Psvane KT88-T again in my MC275, but it blew the fuse immediately after switching on mC275.:tears:

I checked with another fuse with Reissue Gold Lion KT88 and MC275 plays good music. I am doubting there is a problem in Psvane tubes and asked Rachel to inspect at their site and replace them with good quad matched tubes.

I hope they will provide me a kind and good support on my issue.

 

[ssmith3046]

Try the Gold Lion 12ax7 reissues. They're the best new 12ax7 I've found.

 

[kj510]

Update about my Psvane KT88-T

I have sent my Grade A quad to GF Canada for testing and just had a reply that the all tubes had almost 100% emission which means the tube is very strong with longer life, but flows more current. Manual Bias Amp can adjust but total current flow of my tubes blows my MC275 fuse. So we might have to mention that we use the tubes for auto bias amp. However, they will replace with the 90% emission Grade A quad matched tubes for me. Hope it will work on my MC275. And hope my case will be a useful experience for those who are considering Psvane KT88-T Grade A quad in the future. I will update once I receive my replacement.:thmbsp:

 

[arien]

Hi Kj510,

Thank for the update....

Just a question: have you had a chance to confirm this with Mcintosh? Is this really the case when you have an amp that's auto bias (later models)? There is a facility in the Mcintosh website called "Ask an Expert".

cheers

 

[kj510]

Not confirmed with McIntosh

Hi arien,

I have not contacted McIntosh Japan, as I thought they won't comment using non-McIntosh tube, or insist me to use McIntosh tubes. If my replacement works properly, I would be happy!
And my 3 other quads (GL reissue, SED and Sylvania 6550) are working fine.

However, I will update once I receive the replacement. I seems that it will take about 2 weeks as they are sending tubes from Hong Kong to Canada, and will test the tubes suitable to my amp, then send a quad to Japan. I am happy if I receive a trouble-free tubes to my amp.

 

[kj510]

Received a replacement quad pair yesterday from Canada. They are now only 8 hours on my MC275 and seems working fine so far. It was written 86% emission tubes. They are shorter length than my previous pair and should be able to use the cage. I will need a long burn-in from now, the sonic now is fine though but too early to compare with other tubes. When we make a purchase, we might need to specify we use tubes for MC275, otherwise you might have the same issue which I had. However, my problem seems solved with the replacement and I am happy with the result.

 

[arien]

Good to know that kj510:thmbsp:....i'm sure that sound will get better and better as you burn-in the tubes....now it's time to do listening and enjoy the music

 

[kj510]

Tubes are cool!

Thanks Arien, tubes are now about 33 hours and the sonic is improving. Surprisingly, those tubes operate very cool compare with other brands, you can touch tubes and not get burnt. I asked Grant Fidelity about it and knew cool tubes tend to last longer, it is good. And asked when I repeat buying the tubes for MC275, I should ask them tubes for "moderate emission to match amp bias setting". Hope this helps for MC275 user buying Psvane KT88-T in the future!

 

[zagoreos]

The more I am digging through these threads, the more confused I am getting...
Maybe I need a winter vacation?
So, here goes:

I am using a C2200 connected to an MC275 (version V).

All interconnects on my system are balanced Jorma 2 cables. Even my turntable is connected to the phono stage with balanced cables.

The power tubes on the MC275 are the Shuguang Black Treasure KT88-Z.
V-1 tube is a plain EH, since using something more elaborate would not bring anything better.
All the rest of the tubes are Golden Lion ECC81 new version (gold pins).
Is that wrong? Should I have different types on different positions?

 

[ron-c]

You will need 12ax7a and 12at7a 9 pin type tubes in the proper positions. One tube type in all locations will not allow the amp to spec out or make full power.
I use NOS US military 6201 and 5751 RCA and GE tubes in my MC275 V with the KT88z tubes and it sounds superb.

thanks,
Ron-C

 

[twiiii]

Are any of you guys using a good distortion analyzer and signal generator to verify your results or are you just guessing? I used to hall my two 275 originals to the shop where I worked or the radio station and connect them up and replace or swap tubes to get the best performance every 6 months. Also, when Davie or Tom. Jr came to town for the annual Mac clinics I would take them in. I don't remember which miniature tubes gave the best performance, it doesn't matter that was 43 to 49 years ago. I am so thankful for SS today. Replacing $300.00 worth of tubes in todays money was a challenge, while in school every 6 months. I wouldn't attempt tube rolling without proper testing today. I would love to have a new C2500, but the tube issue will keep me away.

 

[ron-c]

The C2500 does not use expensive tubes and it will perform very well with average or older tubes. It is not uncommon to have McIntosh preamps run a decade or more on the original tubes and meet all specifications. Yes MC275 are heavy beast to carry about.

Thanks,
Ron-C

 

[zagoreos]

You will need 12ax7a and 12at7a 9 pin type tubes in the proper positions. One tube type in all locations will not allow the amp to spec out or make full power.
I use NOS US military 6201 and 5751 RCA and GE tubes in my MC275 V with the KT88z tubes and it sounds superb.

thanks,
Ron-C

Thanx Ron,
I have just checked again using a stronger light, and two of the tubes are actually ECC83's , so I guess they are OK.
Sorry for the trouble...

 

[twiiii]

In order to keep my original C-22 below specs like new I had to at least change one tube every 6 months. I don't know if it makes a difference for the newer products, but our local voltage swings from 123 to 125.2 volts. Great for making power, The only way we could derive long service from our tubes at the station was to step down the power at the stations transformer to 117 and leave the miniature tubes on 24 hour per day with adequate ventilation. We could go years that way, also. Power supply tubes were changed on a schedule and tubes for power amps etc were checked every six months and if passed replaced bi annually. Of the MC-60, 75, 240 and 275, the 240 seemed to eat the most tubes of the amps that I owned. A friend of mine has my MC-60's and has only replaced the tubes two or three times in 40 years.

 

[alfa]

Ordered matched quad of Shuguang treasure kt88-z...I'll compare it with GLs...

Hi I also have the MC275 markvi. Did you push through with the Psvanes kt88's?

How does the psvane, gold lion and stock tubes compare with each other. Many thanks

 

[kj510]

My Psvane KT88-T quad T-collection Grade A were sparked and blown after 8 months (about 2400 hours) with a big noise... it blew Isoclean too. Sound was good but not sure about the quality/reliability... Now I am using Sylvania 6550 which sounds great.

I was using A2900s too and they are good. But expensive. I found Siemens ECC801s instead and which sounds as good/powerful as A2900 (and cheaper).

 

[arien]

Hi I also have the MC275 markvi. Did you push through with the Psvanes kt88's?

How does the psvane, gold lion and stock tubes compare with each other. Many thanks

Sorry for late response, i did not try the Psvane kt88s, at the moment still running the shuguang treasure kt88-z