SETs

[pigmode]

Who else is using, or is interested in SETs?

My new system is breaking in beautifully and I've pretty much made the arbitrary decision to stick with SETs through this and the next upgrade.;)

Why? because I love my new system, and there's zilch for audio in this town--I can't afford to experiment anymore, and will stick with this proven formula.

[Steve Hoffman]

I use SET's in two of my systems. Nice sound!

[akshobhyavajra]

Same here - I use a SET in my primary system - love it.

[Metralla]

Ditto - 8 watt SET amps in my main system. Full Music mesh-anode 300B output valves (China), Sylvania JAN VT-229 driver tubes (USA - from 1944), Mullard GZ37 rectifiers (UK). In my apartment I have all the volume I need.

Regards,
Geoff

[JakeLA]

I have Atma-Sphere OTLs. Would like to hear an SET in my system -- maybe someone wants to trade for a couple of weeks?

[Jim Ricketts]

"Full Music mesh-anode 300B output valves (China)"

I think VERY highly of these tubes, esp the latest version with the ceramic base and gold pins. Think about cryo treating the tubes. We have a review publishing 1-Nov and the meshies were cryoed with even better results.

[Steve Hoffman]

Jimbo,

Can you explain what "Cryo-ing" is and does, and who does it?

[Metralla]

Originally posted by Jim Ricketts
"Full Music mesh-anode 300B output valves (China)"

I think VERY highly of these tubes, esp the latest version with the ceramic base and gold pins. Think about cryo treating the tubes.
Jim,

I'd definitely buy another pair of these tubes, and I would spring for the deluxe version with the ceramic base and gold pins, and even more exciting would to have a cryogenically-treated pair. You have me drooling.

Where will we see your review published?

Regards,
Geoff

[Jim Ricketts]

Steve,
Cryogenic treatment is "the ultra low temperature processing of materials to enhance their desired metallurgical and structural properties." This seems to provide a smoother, clearer sound when applied to metals, tubes, cables...even CD's....supposedly. Here's a link to a lab in AZ that provides more information to what they do and what they do it to.

http://www.cryogenicsinternational.com/

Be sure to read the audio related links at the bottom.



Geoff,
Check my tmh audio website (link on Steve's homepage) under "Reviews" as it is scheduled for 1-Nov and will be added at that time. Until it's official, that's the best I can do.

[Ambel]

Single Ended Directly heated triodes.
They are wonderful. For me It's the original Western Electric 300B
from the 30's, 40's, 50's, and the 60's later vintage and new production
forget about it. Nothing comes close to sound of these puppies.
And here's the list of SET amps that I had 45, 2A3, 10Y/Vt-25 and 71A.
They are not at par with the WE 300B.
The WE 300B engraved version is the ultimate tube.

[darkstar]

300B Full Music Meshplates in Welborne Labs Laurel Ultimates.

yumm.

SET + horns + vinyl > sex!

[Metralla]

Originally posted by darkstar
300B Full Music Meshplates in Welborne Labs Laurel Ultimates.
Ultimate Upgrade Laurel IIx here also. What other valves do you use, darkstar? Are you still using the NOS Mullard GZ37 rectifiers that come with the Ultimate Upgrade?

The driver tubes that come with this version of Ron Welborne's amps are NOS Philips, which are quite good, but I swapped them for JAN Sylvania VT-229s made during the War. A small but very worthwhile improvement - you can usually score these for $30 a pair.

I also have a pair of Full Music 274B rectifiers (directly-heated cathode) but I haven't tried them yet. These don't have the really nice "slow start" action of the Mullards, but do have a little of it.

For those who don't know (but are interested), "slow start" means that the large B+ potential is not applied across the cathode-anode of the output valve immediately, but after a short period, allowing the cathode (directly-heated in the case of the 300B) to get to operating temperature.

This delay prevents "cathode stripping" wherein the cathode material is adversely affected by the high potential, which is tends to pull negative ions out of the cathode material when it is not hot enough.

Another way to achieve "slow start" is to have a way of applying the B+ voltage after the amp has been turned on. This can be done through a second switch (though considering the large voltage this has to be well-designed) or some type of relay.

I'm going to try these rectifier tubes in due course, but I am keeping my system unchanged at the moment pending the arrival of my Ric Schultz modified Sony XA-777ES.

Regards,
Geoff

[darkstar]

I'm still using the GZ37's because I like the way they look :)

I have also some metal base GZ34s and a pair of Mullard 5AR4s.

I still can't fault the GZ37, so stay it does.

Also have VT229 drivers, and a pair of 5691s, also hard to say which is my favorite. The vt229s are in there currently.

I tube roll every few weeks, trying to hit on a 'mix' that will be a clear winner.

So far, nothing sounds bad in combo, so it's hard to pick favorites.

[Metralla]

darkstar,

I actually have an big collection of NOS 6SL7-type valves, including many VT229s, 5691s, ECC35 (Mullards and Adzams), Brimars (including the military version), Valvos (from the 1950s), and the domestics - Sylvania, RCA, Philips, Tung Sol, Ken Rad, WE. I have some Tung Sol 6SU7s as well. I must have at least 40 pairs of NOS tubes of this style. I hope to try them all out one day. :)

I got a bit excited about these tubes when I bought my Laurels 12 months ago and I have collected as many different makes/styles as I could - really, just for fun. I have only made the one swap and that was the original Philips for the Sylvania VT229.

I agree that the GZ37s look cool - but so do those metal-base GZ34s you have.

Regards,
Geoff

[Ambel]

Here's the other half of my mono block SET 300B amp . OPT's are
Tamura F-5002, Black Gate Filter caps, WE 300B (1956), RCA 5692,
RCA 5V4G, Mils spec UTC pwr transformer, and choke. Mils-spec
aerospace silver hook-up wire, Audio Note Copper in oil coupling caps.

[pigmode]

Wow! Ambel, is that the WE? What vintage?

Maybe we should start checking in with the speakers we are using. I have the Galante Rhapsody--a dual-concentric bass reflex design.

Here's a pic of my Fi X with Magnaquest OPT.

[Ambel]

Here's the list of speakers that I'm using with my 300B amp.
DIY Transmission line with Access/Focal 6B and HiVi RT-2 Isometric
ribbon tweeters, Altec 604E open baffle, Altec 605A, Lowther DX-3, and
JBL L-65. The second system is SET 10Y/VT-25 amp driving the Altec
VOT Flamenco speakers here a pic of the amp with Electraprint silver OPT's.

[Metralla]

Originally posted by Jim Ricketts
We have a review publishing 1-Nov and the meshies were cryoed with even better results.
Jim,

Just finished reading the review. Excellent review of a very nice WAVAC 300B SET, and one that is far more affordable. It's nice to see that you can get 95% of the EC sound for one third of the cost.

I'm delighted to read in this review that Wayne Donnelly feels that the meshies are still running head to head with the WEs. I figure that I can't really afford to indulge in NOS Western Electrics, so it's reassuring to know that I can stay with the far cheaper option.

If you want to see how far some folks will go to get classic WE 300Bs (especially the engraved ones), here (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1393075139) is a healthy auction. $1975 (and it's not done yet) is more than I paid for my amps, and that was with tubes (KR Enterprise).

Regards,
Geoff

[indy mike]

What are you SET guys getting in the wacky ways of sonic bliss? My tubes experience is tied to EL-34's and I wonder what goes on with 300B's...

[pigmode]

Originally posted by indy mike
What are you SET guys getting in the wacky ways of sonic bliss? My tubes experience is tied to EL-34's and I wonder what goes on with 300B's...

I moved from an EL 34 based amp to a 2A3/45 SET. For me the difference was pronounced and hard to explain, and I can't generalize on anything but my own limited experience. Earlier, if someone told me an amp could make this much of a difference in sound I would have laughed.

Most importantly, tonality is more full. The music seems to fill your "insides" as opposed to just filling the room. I feel touched by the music in a physical sense, and I'd guess this has something to do with midrange reproduction.

The sound has both more texture and is more liquid. My PP EL 34s seemed much more sterile by comparison.

I'll stop now because I don't want to come off like someone enamoured with his new toys. However, I will say this: with my PP EL 34s, my tweaks were always directed at trying to fix something or another. One fix would move the sound way over in one direction, and another would move somewhere else. It was never quite "there". With my SET, there is nothing to fix. I have some ICs and tubes waiting, but these are for exploring possibilities and potentialities...

[indy mike]

It's fun to play mix and match (as long as the budget permits)! I have several brands of El-34's, settled on Some Siemen's from E. Germany (thanks boss o' the sonic sauce SH for the hint on those), tracked down some NOS Mullard GZ-34's (thanks sckott), and found some nice RCA 7199's. Down the road I'd like to try some Curcio mods for my amps - they're not too expensive, and best of all they don't need physical modification to the amp's chassis. Do those 300B's throw off a lot more heat than my EL-34's?

[Drew]

A 300b in a single ended configuration is a class A amplifier, so it will be very hot. Even Class A solid state amps are very hot. The 2A3 in my Bottlehead Paramour is hot enough to sear skin (I found out by reaching over the top of it to turn it off and dropping my forearm down into it). D'oh!

[Metralla]

Drew,

I'm not sure your reasoning is completely sound. As far as transistor amps go, you are certainly correct. A class A sand amp will throw off a lot more heat than a class AB tranny amp. I own a Kostas Metaxas A1 - 100w of pure class A. It has very efficient chimney-style heat sinks on the front and it hardly gets warm, but it does heat up the room.

I thinking that a class A transistor amp probably does not give off as much heat any big valve. I'd say that the size of the filament in the valve contributes most of the heat, and I'd estimate (using my hand) that the Mullard GZ37 rectifier puts out about 2/3 as much heat as the Full Music 300B in my Laurels. There are really big filaments (directly-heated cathode) in the 300B. The driver tube - a 6SL7 - is certainly not as hot as either, and the little pentode is only slightly warm.

I'm going to go out on a limb and say that the heat generated is roughly proportional to the number of big tubes (output valves and rectifiers). It's commonly accepted that the AtmaSphere OTLs are the hottest valve amps - lots of bottles there.

I think that my BAT VK-50SE preamp puts out more heat than one of my power amps - it has 8 x 6H30 twin triodes and they run pretty hot for a small signal tube.

I'm not denying that the glass envelope gets very hot - but am talking about overall heat generation. I'd say that a push-pull amp with 4 EL34s and a valve rectifier will give off as much heat as a SET.

Regards,
Metralla

[pigmode]

That's very interesting about the Paramour. My X puts out considerably less heat than my PP El34. I've brushed against the 2A3 tube a number of times already and it never really gets all that hot. There's no way you can get burned by that tube. Might be the circuit topology, and the open design of the X must be a factor as well.

I like having to roll only one output tube per channel., that way really good NOS tubes become more easily affordable.

[indy mike]

I'm in a particular pickle - I have an almost 2 year old and a wife who's not a lover of clunky ol', red-hot stereo equipment; this evening she looked over at my Dynaco's and said "what are those?" - the not so subtle hint was, back to my hidden in the entertainment center solid state amp. Guess I'll live vicariously through you boys whith the neat-o toys...