Eastern Electric M-88 Integrated...New Tubes?

Peter J · « **on:** 1 Nov 2012, 08:49 pm »

I've been messing with audio gear for most of my adult life, but never have owned tube gear until I got this integrated. I have to say I get it now when I read something about the richness of tubes. In spite of their quirks, I'm a believer.

All that being said, I just don't know a lot about them. Here's the deal; recently was getting some noise on one channel and because it's easy on this amp, I checked the bias. Had one tube that was way off, and when I tried to adjust, there was no response. I assumed I had a bad tube and swapping tube position confirmed this. The suspect tube also doesn't get hot like the other three, which would also lead me to the same conclusion...correct?

I think I need new tubes, these are the originals and I suppose I could replace with same...or something else, but what? It appears it's customary to replace them as matched quads, is that the case? Pairs? Singles? Looks like lots to choose from, but I'm certainly not gonna drop some of the big money I've seen exotics go for. It it really worth it?

I'm music-less, (well OK, there are other systems in the house

) and don't know what I don't know when it comes to tubes, Help!

wilsynet · « **Reply #1 on:** 1 Nov 2012, 09:05 pm »

$325 for a quad:

http://www.grantfidelity.com/site/Shuguang_Treasure_KT88-Z_Grade_B

roscoeiii · « **Reply #2 on:** 1 Nov 2012, 09:20 pm »

And those quads can be found for less elsewhere, but you don' t get the Grant Fidelity Quality Control.

Not sure if the M-88 can accommodate them, but if so, you might look into KT120s. They are getting rave reviews, BUT you must confirm that they will work in your amp.

richidoo · « **Reply #3 on:** 1 Nov 2012, 09:42 pm »

Nice amp! The US importer, Bill O'Connell, will have some sage advice for you.

If it were me, I'd try the Shuguang Black Treasure KT88, or Psvane KT88-T, they are similar tubes, since same people designed them for the 2 companies, they work at Psvane now, but I've not heard a specific review of PsVane power tubes. All the treasures I have heard were excellent (best.) For something cheaper the Gold Lion Genelec KT88, matched quad from Jim McShane. Something even cheaper SED 6550 "Winged C" is pretty good. The KT120s are nice if the amp can power them.

Peter J · « **Reply #4 on:** 1 Nov 2012, 10:30 pm »

Quote from: richidoo on 1 Nov 2012, 09:42 pm

Nice amp! The US importer, Bill O'Connell, will have some sage advice for you.

If it were me, I'd try the Shuguang Black Treasure KT88, or Psvane KT88-T, they are similar tubes, since same people designed them for the 2 companies, they work at Psvane now, but I've not heard a specific review of PsVane power tubes. All the treasures I have heard were excellent (best.) For something cheaper the Gold Lion Genelec KT88, matched quad from Jim McShane. Something even cheaper SED 6550 "Winged C" is pretty good. The KT120s are nice if the amp can power them.

I did send an email to Bill, figuring he'd know what's good and not-so-good. Thought I'd mine the minds here as well. I have to admit the $$ for the Black Treasure takes me a little aback, but like all audio, perspective changes as we dive deeper into the hobby, so I'm acclimating.

SteveFord · « **Reply #5 on:** 1 Nov 2012, 11:35 pm »

It looks like there's individual tube biasing on that model so if the other 3 tubes are still good you could just go with a single tube - same as what came out, of course.

JakeJ · « **Reply #6 on:** 2 Nov 2012, 12:08 am »

Good advice so far, thank you gentlemen.

It does depend on the depth of your pockets. I run the Gold Lion re-issues and they are nice. Another possibility would be the Penta Labs KT88-SC which I also have a set of.

Think about this option as well -
http://www.cryoset.com/catalog/product_info.php?cPath=22_27&products_id=90&osCsid=88147f3752a300f45b4207363a04870f

Many listeners have been very happy with their tubes and you can find some threads here about Cryoset and cryogenically treated tubes in general. My next tubes will be cryo'd.

All our best and please keep us posted on you experience!

(Edited for spelling errors)

Freo-1 · « **Reply #7 on:** 2 Nov 2012, 01:12 am »

I had that amp for awhile. Nice sound.

The tubes that I found sounded the best was Canada Fuller KT88 (clear glass), in or NOS GE 6550A.

Ericus Rex · « **Reply #8 on:** 2 Nov 2012, 12:08 pm »

Quote from: SteveFord on 1 Nov 2012, 11:35 pm

It looks like there's individual tube biasing on that model so if the other 3 tubes are still good you could just go with a single tube - same as what came out, of course.

+1, unless you want to try a different flavor of course!

Andre2 · « **Reply #9 on:** 2 Nov 2012, 02:27 pm »

I was hearing some distortion with myEE kt88 lately, so checked the back and I could not bias two tubes. So, I ordered this set:

http://www.cryoset.com/catalog/product_info.php?cPath=22_27&products_id=90&osCsid=88147f3752a300f45b4207363a04870f

Let's see how they sound when they arrive next week. Cheers.

Andre2 · « **Reply #10 on:** 2 Nov 2012, 03:15 pm »

So, I am a professional Structural Engineer (design of steel buildings/structures etc...) who hated electricity related courses in college. But, here where I work I have a good double-e (that's how electrical engineers call themselves, for those who don't know

) on the next office from me.

I was sharing with him my tube amp problem that could not bias, and my lack of knowledge in this area, and why the tube amp sounds better than my solid state amps. Thus, ever helpful, Richard emailed me this in pdf for my weekend reading.

Sooo, I am here to share with my AC virtual friends, so we all can become more knowledgeable on the subject.

There you go. CHEERS!

http://www.ax84.com/static/p1x/p1-ex-theory.pdf

Ericus Rex · « **Reply #11 on:** 2 Nov 2012, 04:02 pm »

Andre, that link looks to have some very good information in it. I've printed it out to read later today.

Another thought, PeterJ, after you get your replacement tube(s) if you still have any trouble with the biasing turn the amp off immediately and take it in for evaluation. It is possible you have something wrong with the bias circuit that then killed the tube (as opposed to the tube just going bad). Running a new tube wouldn't fix the problem, in that case, and you'd then just kill the new tube too. Not trying to scare you here, just don't want you to lose any more money than absolutely necessary.

Tubes definitely are a bit more maintenance than SS but they are absolutely worth the extra effort and expense.

Andre2 · « **Reply #12 on:** 2 Nov 2012, 04:19 pm »

Ericus, Thanks for your post above. I have a similar problem as the OP, that is:

"I checked the bias. Had ~~one~~ two tubes that ~~was~~ were way off, and when I tried to adjust, there was no response."

I guess another way of checking if it is the circuit or the tube, is to swap the 'good' tube and put it on the location of the' bad' tube. I will do that tonight. Too bad that I already ordered 4 new tubes.

Gopher · « **Reply #13 on:** 2 Nov 2012, 05:57 pm »

Quote from: wilsynet on 1 Nov 2012, 09:05 pm

$325 for a quad:

http://www.grantfidelity.com/site/Shuguang_Treasure_KT88-Z_Grade_B

$220 here if you're willing to pass on grants' matching service: http://www.goodcomponent.com/Shuguang%20Treasure%20tube.html

JakeJ · « **Reply #14 on:** 3 Nov 2012, 02:37 am »

Andre2,

Thanks for the link to the tube theory article. Looks good, after a quick perusal, I also downloaded a copy for future reading.

Please let us know what you think about the cryo'd GL tubes. Start a new thread, please, if you would as I would like to document our members experiences with cryogenically treated tubes with a thread directly titled for the subject. Thanks.

E-Rex,

Quote from: Ericus Rex on 2 Nov 2012, 04:02 pm

Andre, that link looks to have some very good information in it. I've printed it out to read later today.

Another thought, PeterJ, after you get your replacement tube(s) if you still have any trouble with the biasing turn the amp off immediately and take it in for evaluation. It is possible you have something wrong with the bias circuit that then killed the tube (as opposed to the tube just going bad). Running a new tube wouldn't fix the problem, in that case, and you'd then just kill the new tube too. Not trying to scare you here, just don't want you to lose any more money than absolutely necessary.

Very good advice!

Quote

Tubes definitely are a bit more maintenance than SS but they are absolutely worth the extra effort and expense.

I couldn't agree more.

To all vacuum tube using music lovers, if you own a tube amp and it has a bias adjustment for the output tubes then you need to check it periodically. How often will be (hopefully) stated in your owner's manual. If not then make a habit of it every three to four months, depending on the amount of time the amp is on. I listen mostly on weekends but do some listening on the weekdays so I check it right around three months. For those who don't get that much listening time in you may be able to check it once every six months. If you listen every day and almost constantly on the weekends then I would check the bias once a month.

Gentlemen, please feel free to weigh in on this subject. I welcome your input.

FYI - I am running non-cryo'd GL re-issue tubes in my VAC PA-160 amps (monoblocks). I have been using them for ~1 year, maybe a bit more. Out of curiousity I pulled and tested them to see where they are in their life-expectancy and they are about half gone. This is based on what the tested at new and what my tester says is the minimum acceptable reading. Next I did the life test and they are still quite strong.

I also have an octet of matched non-cryo'd Penta Labs KT88-SC tubes for back-ups and the reason they are back-ups is that when I compared them to the new GL's I heard/felt/sensed the GLs are a bit more refined and ever-so-slightly more resolving of details. However, the Pentas are certainly no sonic slouches and in the right circuit may trump the GL's. Next, I have an octet of GL KT77's but I don't think they are the preferred tube for these amps (just my .02). I really would like to get an octet of the Tung-Sol 6550 re-issues to see what they sound like in this particular circuit. Curiousity is one of my banes in life.

Jake

mjosef · « **Reply #15 on:** 3 Nov 2012, 03:14 am »

I recommend the GL KT88 reissue also. Full bodied sweet sound, just a step on the warm side of 'neutral' vs the reissue TS 6550 which I thought was a tad 'dry' but dynamic (more than the GL) and falls on the other side of that 'neutral' line in my imagination.

It all depends on your 'sound-taste' preference.

I might more apt to go for the TS (cheaper) and then experiment with the small signal tubes(much more affordable options) to dial in the sound my taste dictates. There is also the EH 88 which is decent (and cheaper yet).

Andre2 · « **Reply #16 on:** 3 Nov 2012, 04:38 pm »

Quote from: JakeJ on 3 Nov 2012, 02:37 am

To all vacuum tube using music lovers, if you own a tube amp and it has a bias adjustment for the output tubes then you need to check it periodically. How often will be (hopefully) stated in your owner's manual. If not then make a habit of it every three to four months, depending on the amount of time the amp is on. I listen mostly on weekends but do some listening on the weekdays so I check it right around three months. For those who don't get that much listening time in you may be able to check it once every six months. If you listen every day and almost constantly on the weekends then I would check the bias once a month.[/b]

Jake, thanks for posting this schedule. I got my ee m88 almost a year ago, my first tube amp, and I never checked the tubes prior to this week. My new tubes have shipped, will open a new thread with my impressions on them next week.

Andre2 · « **Reply #17 on:** 4 Nov 2012, 03:12 am »

what should we do to check the other smaller tubes 12ax7 ? How do I know if these are okay or not?

morganc · « **Reply #18 on:** 4 Nov 2012, 06:28 am »

Quote from: Andre2 on 4 Nov 2012, 03:12 am

what should we do to check the other smaller tubes 12ax7 ? How do I know if these are okay or not?

You can buy a tube tester, find a friend with a tube tester, or do like most of us and buy new tubes and see how it sounds.

Ericus Rex · « **Reply #19 on:** 4 Nov 2012, 12:24 pm »

Quote from: Andre2 on 4 Nov 2012, 03:12 am

what should we do to check the other smaller tubes 12ax7 ? How do I know if these are okay or not?

If you've got a noise or hum then the ole' swap from L to R channel (only one type at a time) will help you figure out which tube is the noisy one. You may have to rebias after the swap. If you don't have any noise then the tester option is the only one. In all likelihood, you won't ever wear out your 12AX7s. I've never worn out a 9 pin, but I've had many die prematurely.