Harmonix EL34???

[maxg]

These are the tubes that came with my amp (http://www.tsakiridis-devices.com/Powerhouse.htm - ultalinear pentode 70 wpc).

There are 8 of them in total.

Question: Worth rolling for something else? If so what?

According to the Tubestore.com this tube:

"The new Electro-Harmonix EL34EH is extremely musical, with a sound that is rich, smooth, and highly detailed without being edgy. It is the perfect EL34 for vintage equipment and a sure way to improve the performance of modern equipment. According to the technical journal, Vacuum Tube Valley, the "...new EL34EH comes very close to the sonics of a Mullard EL34..." They go on to say, "The Electro-Harmonix tube is balanced throughout the entire music spectrum. Bass goes deep and is tight, mids are sweet and well defined and highs are detailed and extended."

I presume coming close to the Mullard is a good thing. Are Mullards recognised as being the best EL34's around? How muc would I expect to pay for 8 reasonably matching Mullards?

[Deang]

The newer EH tubes, almost regardless of type, are receiving raves from just about everyone that has tried them. As far as sounding like Mullards -- who knows. Output tubes of the Mullard variety are so ridiculously expensive that many just can't afford to try them. Also, there were several different types of Mullard EL-34, and my understanding is that they all sounded somewhat different from each other.

I know I'll probably get slammed for saying this, but in a pentode/ultralinear amp, it's almost equally effective just rolling the driver tubes. Changing out the four JAN Philips 6922's for Amperex 7308's in the Bruce Moore Dual 70 made a big difference.

Since you already have a nice set of EH EL-34's, you might try some JJ Teslas down the road.

[JBryan]

Max,

NIce looking amp ya got there! I have a little experience with EL-34s and of the EH offerings, I'd suggest the "fat bottle" 6CA7s. They're actually copies of the early Sylvanias I think while the ones you refer to are the EH version of the Mullards. The "Fat Bottles" seem to do a little better in the bass - tighter and more defined. I thought the Mullard-type EHs were a bit muddy down under. If you listen to rock at high SPLs then the "fat Bottles" would do you well. If you prefer jazz or classical, then I'd suggest the Svetlana ("winged-C") EL-34s. They are also copies of the fabled Mullards but I think they are more musical and have a cleaner midrange. They lack a little bass compared to the "Fat Bottles" but sound better everywhere else which may make a difference with your musical preferences.

On another note, I like dual mono amps and have been enjoying a 6C33c amp with a similar set up to yours. I thought the DM idea would indicate a separate power supply for each channel (essentially being monoblocks built into a single chassis) but your amp doesn't appear to have that feature. Have you noticed any difference in separation from monoblocks? Also, I was looking at the specs and wonder how the amp does noise-wise with your speakers. Please fill us in on your impressions as curious minds want to know. Thanks, Bryan

[JBryan]

Also, a octet of NOS Mullards will set you back at least $500 and much more for the metal-based version. Not the best bang for the $ in my opinion and the Svets and EHs offer a very close copy and a great value. YMMV - Have fun, Bryan

[sunnysal]

max, it is more a money thing. the mullards are SO expensive that you really need to consider price versus benefit before investing. the EH EL34s are great tubes, for the money they are impossible to beat IMHO. tony

[mobile homeless]

Changing out an octet of EL-34 is sure not going to do your pocketbook any favors... I think Jbryan makes some good comments and solid recs here. Ultimately, I would go with Dean's suggestion of upgrading your input/driver tubes first as this will be cheaper and bring about a serious change for the better depending on your selection.

On the output options, I would instead first opt for a complete set of the very best KT-88 you can find with perhaps Svetlana an option if you want new. Why? Because this would REALLY offer a very different presentation than the EL-34 outputs and I would rather go with this option for a totally different take, bringing more of a "two amplifiers in one" result. Granted, the KT-88 is not my favorite tube per say but this would be a no brainer for bringing another perspective from you amp. They have a different signature than the EL-34 slightly more clear and dynamic but not as much midrange dimension and warmth. Since you have run the KT-88 in the past, you might have some left over. Alas, it will be costly getting the matched quads... totally eight. But it would be fun to sub them in. I was also opt for the SWITCHABLE TRIODE WIRED Option since you know the designer. This is not a difficult mod to do and since he offers it, I would grab it. I also prefer the KT-88 in triode mode and this would be another no brainer. This would give your amp an even more convertable nature.

Jbryan brings up another important point as well with his dual mono comments. Unless the online pic is just ONE power supply, you are apparently running your amps with this ONE POWER SUPPLY TRANS. While this might not be critical depending, just wonderer where the dual mono starts in that amp.

Have you ever taken off the bottom of your amp and PS to see what caps and resistors he uses?

kh

[DRBILL]

I have had some difficulties using 6CA7 EH Fatboys in Dynakits. The screen grid glows red. This is not a good thing! Life expectancy drops to nothing. No problem with Svetlana EL34's.

Anybody else observed this?

FATHER BILL

[NOSValves]

JBryan and Max

Have you tried the Fat Bottle EI 6CA7's ? I run them now and then in my Mark III's and get the same impressions you stated with the Fat Bottle EH's .

I have used Svetlana KT88 flying C and S , EH KT88 ,Sovtek KT88, USA 6550A , Tungsol 6550 , EI Fat Bottle 6CA7's, Svetlana EL34 , Golden Aero KT88 ( Chinese GEC Copy)

My Favorites so far

#1 Tungsol 6550 ( Smooth, Dynamic they just sound oh so right, running strapped in triode or UT)

#2 Golden Aero KT88 (this was a real surprise but not sure about longevity sound very similar to above)

#3 Fat Bottle 6CA7 EI ( Very nice bass for a EL34 when running in UT this is my favorite in Triode there a little weak for me)

#4 Svetlana C & S , EH and Sovtek ( All about a tied slightly edgy but expectable they sound much better in triode)

#5 the rest listed none of them float my boat the USA 6550's I have tried were all weak and would not hold steady bias so hard to make any judgment.

Front end tube do make a difference but in my amps the output tubes and output topology does make a difference in a big way also mostly changing topology and tube type imparts the major changes.

Craig

[NOSValves]

DRBILL,

What Dynaco's did you run them in and with what rectifier and what Bias settings ? I was thinking about trying them in my Mark III's just for kicks the next time I order something from uncle Ned.

Craig

[AnalOg]

Craig,

Where did you find the best price on the Golden Aero KT88's?

Tom

[JBryan]

Max,

I would agree that the driver tubes will make a big difference in the gain and brightness areas while the power tubes offer extension (especially bass) and fullness. However, I didn't see any divers nor mention of them on the site. Does the amp have a tube driver section and if so, what tubes are used? If its a hybrid (aka Sonic Frontiers, etc.) then you'll definitely want to use warm-sounding tubes like the EHs you have (pretty convenient) or the Svets. Generically, KT-88s sound like brighter, more powerful EL-34s with more bass - a good compromise between the EL-34s and 6550s but they may be too harsh if you use tubes like 12AX7s or run SS in the driver stage. - Bryan

[Guy Landau]

Max,

The price of 8 matched EL34's Mullards can exceed $1k. Is it worth it? For me it was. There are many variants of the Mullard EL-34 tube. The best sounding are the "Big Base" xf1 code and the double getter xf2 is almost as good. The 1950's Amperex double D getter is at least as good as the xf1 but the prices are almost identical.

Try and find early Teslas with the big, brown base, they were manufactured using Mullard tools and they look similar. They will sound better than most new production tube with full midrange and crisp highs and not as machanical. I have not heared the EH tubes myself, but have heared good comments about them.

[DRBILL]

CRAIG,

ST-70 and MARK IV. 1.56 bias as specified. I started out with Zenith (British) NOS GZ34's. I swapped them for some used (tested good) 5U4GB's. That lowered the plate voltage somewhat, but still got the screen incandescence, so I went back to the GZ34's. I swapped in Svetlana EL34's for the EH's and the problem was solved.

The Dynakits are ultralinear which is hard on the screen grids since they are driven with part of the output signal. I think the EH's were flimsy. It might have been a bad run. I bought six. I tossed them.

FATHER BILL+

[sunnysal]

wierd problem dr. bill, I never had problems with my MkIVs and I used a number of different EL34s. I always used 5AR4s (sovtek and chinese). perhaps something is out of whack elsewhere in the dynakit? a bad cap, etc.? tony

[mopar dave]

i have to agree with jbryan about the fat bottle EH's. when i first purchased my chineese amp (audcom) it was alittle bright and not the way i thought a tube amp should sound (simular to my yamaha ss). after rolling input and phase spliter tubes the sound was cleaner and closer to what i had expected, but still did'nt have a tube sound. after changing out the chineese el34 for some svet's i was happier with the sound, but it was not quite what i was looking for or should i say listening for. next tried the EH fat bottles, that was it. the sound i had been waiting for, that tube sound without being too slow or boomy, just the way jbryan explained it. although i'm very happy with the EH fat bottles, i'm thinking of tring a quad of jj's just to satisfy my curiosity. dave

[DRBILL]

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On 11/3/2003 4:25:10 PM sunnysal wrote:

wierd problem dr. bill, I never had problems with my MkIVs and I used a number of different EL34s. I always used 5AR4s (sovtek and chinese). perhaps something is out of whack elsewhere in the dynakit? a bad cap, etc.? tony

----------------

One might have thought so. But that it occurred in two seperate amplifiers and was corrected with different tubes points a finger at the EH Fat Bulbs. I think it was a bad run. Again, ultraliner amplifiers make unusual demands on the screen grid. It has made me cautious about buying more EH tubes. The only reason I bought these was that I was trying to save some kids some bucks. I wound up eating the mistake. I only charged them for the EH's (which went in the trash) and I bought the Svetlanas. This business is as much an art as it is a science. I'm an old f--t but I try to learn something new every day. One thing for sure. At the rate I'm going, I'll be 109 by the time I pay for my bench equipment! But, it keeps me out of the pool halls.

FATHER BILL

[NOSValves]

DRBILL,

Well I would try some fat bottle in my Mark III's but there strapped in triode so your UT theory may still be the culprit and we wouldn't know for sure.

Mopar,

Your amp is Ultra linear maybe this is why your fat bottles are giving you fits heh !

Tom,

I got them from Penta Labs he sells on ebay . I got my Quad for $95 shipped !! Good luck get another set for that.

Craig

[maxg]

God I love this forum!!!

Thank you all for your input.

I think I will try the KT88 option first. I have 6 lying around (Tesla JJ's) from my old amps so I will get a couple more and get the maker to do the biasing thing for me.

The only bad part of that it that this amp is so damn heavy I will give myself a hernia moving it!!!

Nice to know that this time he seems to have chosen the right tube for the job. The last amp I bought from him was populated with 6550 WE Sovteks which, thanks to Kelly, I swapped out for the above mentioned KT88's.

OK - there were some questions about the amps:

1. The dual mono design. Actually I run a dual mono pre-amp too - by the by.

Unfortunately there have been too many changes in my system to be able to tell if the channel separation has been affected by the shared PSU. It is leaps and bounds ahead of anything that I have used before, but that could well be due to the cartrdige - the Shelter 901 - which is simply on another plain from anything I have ever heard before.

2. The insides of the amp. Never looked. There is a metal plate at the bottom which should be easily removable. I will endeavour over the weekend (time permitting) to open it up and take a picture for you all to gaze at and tell me what is there.

I should say that there is no buring need to change anything - I just want to play a little. Right now my system sounds so right to me it raises the hairs on my arms every time I listen to it.

If I were to get really picky I would say that it is a little too adjustable for its own good.

I listen to a fairly broard range of music - from Rock to Classical. As I have it set up now it plays classical perfectly. I can get it to play Rock perfectly as well - but that requires several adjustments:

As in:

1. Adjust the outputs of the pre-amp from normal to aggressive. (Power off the pre - wait 30 seconds - flip a switch on the back - power on - wait 2 minutes for the pre to settle). Total time 3 minutes.

2. Adjust the height of the back of the arm. This cartridge is a little weird. I have found that running it more angled down works better with classical and flatter works better with rock - no idea why. It is not quite as bad as it sounds to do this - I have put 2 tiny nicks in the bass of the arm to mark the spots. Undo 2 alum key bolts - allowing the arm to move freely - hold with one hand at the required height - tighten one (it holds the arm in place) tighten the other and presto - except that I use my Shure Stylus gauge every time. Total time 3-5 minutes - depending on mood.

I have the feeling that were I to get the KT88's I would prefer them for rock and the El34's for classical. Powering down the amp, allowing the tubes to cool, replacing them, powering back on the amps and waiting at least 5 minutes for them to warm up would add another, what? 30 minutes.

Bit of a pain in the backside just to listen to Rock after classical.

To be honest I dont usually bother with any of the above - but when I do.....

[AnalOg]

"To be honest I dont usually bother with any of the above - but when I do....."

Max,

You was beginning to worry me there for a second, I was ready to recommend a good therapist.

Seriously, I find that when I start fiddling to much, its "robbing Peter to pay Paul" situations that leave me frustrated, so I find the best balance between and leave it alone.

Tom

[JBryan]

Max,

Adjusting the VTA by lowering the arm increases bass response but reduces detail. Too much and the bass gets muddy. Raising the arm increases detail and adds air to the midrange but too much and you lose bass. Its always a compromise but it sounds like you've got the idea nailed. I've heard that the Shelter is not very sensitive to VTA so your adjustments must be very minor. Please give us your impressions of the Shelter when you've put a few more hours on it. I'm very interested in your take as I may put one on my xmas list (which I'm sure would be a gift to myself).

In regard to the amp, I'm still curious about the driver section. Does it use tubes and if so, which ones? - Bryan