Tour2ma(ST-70)...

organ

Hey Tour, just wondering if you're still using those Electro Harmonix EL34's? You had the EH in your amp from the pic you posted a few months ago. If you're going to replace those tubes I HIGHLY recommend Svetlana EL-34's.

I've been using my EH for about two months and today my quad of Svets EL34 and a pair of JAN-Philips 7199 just came in. I've been breaking them in for the past 10hrs and the sound is f#ckin killer! The Svets is a huge improvement over the EH. The bass is much warmer, the mids is more plump sounding with more bloom and the highs is awesome. The mids have a "wet n juicy" quality that makes it sound much more realistic. I can also hear more natural ambiance in good recordings. I was listening to Sarah Brightman's "Harem" earlier and her voice sounded so realistic. I was able to hear her spit swirling around in her mouth and lips. It was a very erotic experience!

So whenever you're upgrading be sure to consider the Svet's.

Maurice

gidrah

I'm glad to hear you like the new tubes. Out of curiosity, did you listen with just changing the EL34s? Or did you swap them all at the same time? I had heard good things about the EH EL-34(?)s. I may have to go with the Svetlanas in the future. I haven't heard great things about Westinghouse EL-34s or rectifiers.

Thanks for the heads up on the RCA 7199s btw. If they go anywhere it'll be into tissue paper to be used at a later date after things calm down and I can fully appreciate both them and this amp.

Unfortunately mine is packed away for the move. I hope to put it back into commission soon driving my new fronts. There's a very slim chance that the new speakers will fit in my destined 2-ch room. Where they go the ST-70 follows. I hope to put my 2-ch rig in the basement (much more space) someday, but right now it's not a good option. The house is over a hundred years old and has drainage/waterproofing issues.

organ

Yeah, I swapped them all at once. I will give the other 7199's a try with the Svets. Yeah, the EH tubes get great review. They're very good tubes, but they sound very different than the Svets. Svets have a much warmer sound and EH is brighter.

Your Westinghouse tubes are suppose to be great tubes. Search the archives in audioasylum.com I've seen discussions about Westinghouse there. Vintage rectifier tubes are better quality than the new ones, so you should be safe there. I'm sure Westinghouse was competing with Mullard when they were still around.

You have the most sought after 7199 tubes for ST-70 owners. I'm still looking around for NOS RCA. It's really too bad that we only have one company currently producing 7199's(Sovtek).

What new mains are you getting? Good luck with the move and your new rig.

Maurice

gidrah

I hadn't realized the 7199s were so scarce. My wife bought me this amp for last Christmas off Audiogon and I haven't been able to give it a dedicated listening yet.:) , much less judge and tweak to taste with any given speaker.

My new mains are vintage Altec Lansing. Very large, smooth and efficient. http://clubpolk.polkaudio.com/forum/showthread.php?s=&threadid=11537 Hopefully the change in gain will offset the sensitivity.

organ

Those things are HUGE! Great review in your link there. I've always wanted to try horns to hear their dynamics. Those new speakers can really kick you in the nuts when pushed eh? Do you know their efficiency rating?

Maurice

gidrah

With being in homemade cabinets it's hard to say. I believe these drivers can be around 101 db@1w with the bass horn cabs and 96 db@1w in a smaller (smaller than mine at least) ported cabinet. They aren't just loud, they're effortless. They're loud without any sign of strain. I have a pair of little battery powered Discman speakers taken apart right now. I'm curious to see what they'll do with this little amp.

I was showing them off to my brother when a big crescendo hit and the hairs on the back of neck stood up. I could feel the goosebumps spread down to my feet. I once again giggled like a little schoolgirl. We looked at each other and mouthed the "F" word.

I've been thinking about unpacking that ST-70 since last night. Just to make sure it works before I move it and all. Come to think of it, I think my silver plated speaker cables are in the same box.

organ

AAAh you ****!!!:D Now I really want to hear some horns! That's exactly why I'm interested in them. I always hear about their effortless and dynamic presentation. Their going to sound awesome with your ST-70. Horn speakers were made to go with tubes as their efficiency suggests.
A dealer not too far from me was selling the Klipsch RB3 @ half price several months ago. I should have grabbed them and set up a second system. Let me know how they sound with your ST-70.

Maurice

gidrah

If you'll pay for crating and shipping I'll send you mine for about an hour.

I've heard a few horns. Rear loaded, front loaded, compression, dome, etc. I've even heard 10" midranges on 30" circular wooden horns (thanks to Mike Bates aka Magnetar on AA).

It's easy for them to sound bad, but when they sound good, watch out.

Tour2ma

organ,
Thanks for the heads up. The EH's were NOS that came with the amp. Oldioes, but goodies. Very knowledgeable ebay seller I won the amp from, has been my personal guru. He matches tubes on an $1100 Hickock modied for computer interfacing.

I agree, for modern tubes Svet's are a very good value.

Gidrah,
How long has your ST been down? If it's been a good, long while consider bringing it up on a variac to reform the caps properly.

organ

gidrah,
Nah, my parents would kill me if I bring them into the house for even one minute. How about I pay for packaging and shipping and you send me those 7199's and Westinghouse:D. Do you consider the Klipsch Reference bookshefs as good horns? How did those large horns sound at the inmate's house?

That was a good suggestion from Tour, If you haven't used the amp for a few years you might want to bring it up to a variac. I think my Dynaco's quad cap was leaking because of that. Any good repair shop should have a variac.

Tour,
I think I got an older EH in my batch. I'm sure it's not the NOS variety though. I have an older EH with the sheep face stamp on it. It's also labeled EL34EH. The other 3 don't have the logo and doesn't say EL34EH, just EL-34. All four tubes were matched by thetubestore.com for up to 5% tolerance level. Those Hickok testers are excellent but damn expensive.

Maurice

gidrah

Tour,
Thanks for the warning. I think it'll be about 3 or 4 months of downtime by the time it gets glowing again. Should this be okay?

I'm also getting a tube console stereo. I think it's a GE. It's got speakers in the doors that fold out and a Gerrard phono (needle variety) that folds down, and a tuner. The cool part is that it has aux ins. For this I'll try a variac for sure.

organ,
I like the RB-3s. They're a usually a little overpriced, but look pretty nice. IMHO Klipsch really worked out some of their problems when they went to the tractrix horn (BTW they didn't invent it or anything) and these are in a small enclosure. They are still VERY bright sounding and can be a bit fatiguing for extended listening, but the ringing they were getting from the others horns dropped off quite a bit. The brightness can be off-set by the use or tubes or attributed to user preferrence, whereas nobody likes horns that ring like a bell. My horns (back to me, afterall it's all about me) have a lot of metal surface area, but with the 3 vertical dividers welded into place they are very rigid.

Klipsch is one of the brands that can deffinately make a bad sounding horn. I think they are the main contributor for giving horns a bad rep. I'm sure it'll only get worse unless BB starts selling tube equipment or at least set up decent sound rooms.

The "inmate" I bought them from had them very far apart, pointed to the center of a wall of windows, connected to a mid-fi 5.1 receiver. He was more into the musician side of music. Besides I had ended the bid with BIN and was only there to verify they worked and looked as stated, pay, and haul them away. I drove the whole way back smiling from ear to ear they sounded so good.

Mark

organ

Hey Mark, thanks for the info on Klipsch. I think it's going to be a long time before I try some horns. The reason is that I'd like to get some big mofos like yours so I can start with great horns. This will happen when I get my own place. It will be many years away:(. The Klipsch La Scala looks nice but very pricey.

3-4 months should be fine. The only thing to worry about with stock ST-70's is the quad cap and bias supply. If the quad cap goes, you get a loud hum and crappy sound. If the selenium diode in the bias supply goes, you'll lose your EL-34. Almost all ST-70 owners have replaced the bias supply with better caps(2) and use a silicon diode to replace the old diode. If you want to upgrade the bias supply, www.triodeelectronics.com is selling the kit for $3. I got my kit and quad cap from there. If everything was fine last time you used the amp then your quad cap is still healthy. If you know how to solder, it's better to replace the bias supply sooner.

Another thing to keep in mind before the next poweer up is the bias adjustment. Before turning your amp on, set your bias adjustment to minimum(counter clockwise all the way). The bias will drift before the amp is warmed up. After about 15-30mins, use your multimeter and bring up the bias slowly. Check again after about 1 hour. I keep mine around 1.45V for longer tube life.

Aaah, those rides home with your new toys is always fun because on the way home you're wondering how it's going to sound on your system. You have a killer system there mate, enjoy.

Maurice

Tour2ma

organ,

You've been getting your study on when it comes to tubes... impressive.

Agree that three to four months is OK on the caps. Hard to know exactly how long is too long, but it's out more towards a year.

Nice tip on the bias at re-start. As for the running bias, I've heard varying opinions on running reduced especially since the original design setting is already under max for the EL's.

gidrah

Thanks for the info guys. This'll be my first bias adjustment. Don't give me any tips as I'll forget them by the time I need them and the hands on will do me some good. Mine has had a few mods done to it already. Whether or not they're improvements or not is hard to say.

One of the guys at the local A/V store is redoing his ST-70 with a bunch of stuff from Triode Electronics. He seems quite pleased.

dcarlson

Maurice,

I just came across these. No affiliation or anything.

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=3042232614&category=14993

organ

That's right, I totally forgot the EL34's are running lower than max on the ST-70. I believe each tube runs at 65% power. Just brought them back up to 1.56V. Thanks.

gidrah, yeah Triode Electronics has some nice replacement parts and mods. I'm going to get some nice tube sockets from there. Still looking around for a web store that sells replacement caps and resistors for the driver board though. I'm not planning on getting a modded board. Most of them completely change the original design and you lose the vintage sound. The reason a lot of people modded their amps is becase those 7199 tubes are becoming rare and their price is getting pretty high. Sovtek is the only company making 7199's today. The NOS JAN-Philips is very nice too. That's what I'm using right now.

Derick,
Thanks for the liink. That's what I've been looking at for my future upgrade. I can't get those Klipsch though:(. I'm broke and my parents will probably get a heart attack if I got them. I'm still extremely happy with the LSi.

Maurice