DCC Archive Need some tubular advice...

Well, a disastrous 4th quarter means my toy budget is halved. I'm getting a pair of stand mounted speakers and a modest ASL tube amp. I'll probably just get the ASL AQ1003 DT and the Triangle Titus.

What about SET? There are amps and the appropriate speakers that fit my budget but are they any good for Rock music? Should I stick with the push-pull amp?

 

The answer to your question depends on the size of your listening room and the efficiency and impedence characteristics of your speakers.

It is a myth that SET's can't rock. I use in one of my two systems a 45 based SET producing about 1.7wpc with Tannoy dual concentric speakers. This is in a small room, ultimately I can't break the windows with volume, and it would need more power in a larger room, but the volume is more than satisfactory in a smaller room with exceptional sound. Yes, it rocks very heavily.

In my living room is a 7 wpc PP amp also driving Tannoys. With this I can very easily disturb my neighbors and annoy my wife.

 

I'm not 100% sure, but I believe the ASL AQ1003 comes thru with the Chinese EL34's and 12AU7 tubes that most people complain about. Same with Jolida's 202A which is a comparable model you might want to checkout.

Most people say these amps compare to the Dynaco ST-70's, but you have to buy some better valves first.

I recommend you do some searching for info in the tube forum over at audioasylum.com.

Maybe you might want to consider going vintage... An ST-70 in good shape is less than either of these on Ebay.

 

Push-pulls are incredible, but you have to really explore your options.

Without me gushing all over again about how incredibly cool and re-tweekable (and fun) a Dynaco St-70 is, I'll just say that most of the EL-34's I've tried, the Electro-Harmonix and the Sovteks, both made in Russia by basically the same company, are absolutely easy to obtain, have the strong, comfy sound as most higher-end American tubes, and I'd have to say, short of losing your shirt for a quad of Mullards, they're most enjoyable per-dollar.

I'd really look into getting a ST70. I'm actually building a 3rd one from scratch using NOS and new parts. Yes, I love the ST70s that much, yessir!

Anyone got any A470 or PA-060 trannys they wanna sell cheap? I have a home for em, a shiny vacancy!

 

Sckott, you seem to be going in the same direction (DIY) as me, kinda sorta. I've been looking at schematics on the net for different circuits.

I've been thinking about building a push-pull circuit using 2A3 triodes. I found a schematic over on angela.com. If it doesn't workout, I can always keep them as spares for the bottlehead paramours.

One of the big issues is, as you say, the cost/availability of good output transformers. I've seen ST-70 transformers go for over $100 each on Ebay.

Since I entered the world of DIY, I'm afraid I may never leave.

 

Yes, I agree. Just getting the trannys can mean $300 total, and that's not even entering in the caps and tube sockets, the time to build. Sad, becauxe I have 40% of another Dynaco. I just guess saving a few parts won't hurt.

A great guy and a DIY nutt from NY has done some work using those wild 2A3's. It's Jeremy Epstein's "Free Lunch" found here. He's quite a charactor, and I think using "horizontal" connect-guitar back plates for mount connectors are way cool. Gets the wires over the overhang of the tubes without sending the wires upward, then hanging over.

The Free Lunch is a nice little circut, but you DO have to hunt for a decent tranny. Ahhkkk, that's what it is USUALLY about!

Triode mode just does something different to the sound. Not bad, just different.

My main system still uses a big-honkin power SS amp, but in the basement, it's all DIY, not only for serious listening, but for inexpensive and "worthwile" too.

Trying to use tubes to power electrostatic speakers I have now is both expensive and difficult, but those electrostatics make you feel like the trumpets and drums are IN THE ROOM!

For now, I'm building a couple of homeade Foreplays just to be cocky. They're very cheap to make. Not even sure if I'll sell em, but I'll just get one for the bedroom stereo. Beats having a boombox in there! I'll have pictures. I just have to buy some huge caps and some diodes. The rest is coming, and I have the wood and I need to get some junk pate metal, or aluminum.

I'm also going to build a Free Lunch, but I need to get some other projects off my plate. I know Jeremy is not adverse to get questions about his circut design and ideas for trannys. By spring I'm sure I might bug him w/a few questions!

 

Sckott,

There's some interesting info on that page.

Have you checked out Joseph Esmilla's web page over at http://users.starpower.net/je2a3/welcome.htm?

He compares some (relatively) expensive Tango Transformers with the newer (relatively) inexpensive Hammond 125ESE with a 2A3 amp, from the point of view of a pretty serious do-it-yourselfer and musician.
He even give pics of a square wave going thru the amps and how distorted it can be coming out the other end.

These are all transformers for single ended applications tho.

Pigmode,

I apologize for hijacking this thread away from your original question and I'm not sure if any of this info has been a help to you.

If I didn't have the electronics background that I have (which was completely solid state until 6 months ago) I'd be totally lost within the technobabble.

Single Ended Triode, Push-Pull Triodes, Pentodes modified into Triode mode in a Single Ended Circuit, Pentodes modified into triodes in a Push-pull circuit, Class AB Untralinear...

Your obviously trying to squeeze out the best sound for the dollar, but if I didn't enjoy DIY (and laughing my dog ass off at myself when I screw up), I'd play it safe and go for a vintage (unmodded) Dynaco ST-70 or Mark III.

I think $750 is a lot of cash for that Antique Sound Labs, but thats just IMHO.

I just noticed you do have a thread going in the tube forum of audioasylum.

 

Nothing wrong, Drew! At least you realize many threads have sprouted multiple heads before, here.

Thanks for the info. I like how this guy buils! His speakers look great for tubes! High-efficiancy stuff, very simple.

 

Sckott,

I found some of his schematics over at angela.com, then I did a search for JE Labs.

One of the schematics that used to be over at angela.com is the push-pull 2A3 circuit I'm looking at.

If anyone is interested here is an interesting link (to me) over at svetlana web page. about 2/3 of the way down the page, it explains different amplifier classifications.
http://www.svetlana.com/docs/tubeworks.html

I knew the theory behind most of these before, but since there really is no equivalent to ultralinear in solid state ciruits, that was new info to me.


Have you purchased the constant current source mod for your foreplay yet? I suppose I could scan the schematic if you need it.

You could precure the parts for much less than the $75 that bottlehead is asking, I'd think.

 

All right Sckott, you flushed me out, I'm as vulnerable to flattery as anybody else. Thanks.

My 2A3 amp puts out about 3.5W per channel. This will not rock your world with an 87dB-efficient speaker. But if you get up a little higher, low 90's even, you may be able to live with it. I listen to everything - classical, rock, jazz, reggae, and while the sound does not remind me of the old days when I was sticking my head in the bass bins at Talking Heads concerts, there is something else you get with the SET experience that I enjoy a lot.

You should make an effort to hear a system with your own ears before you jump in - some people just don't care about what the SET systems add, they just want "pump."

While I have some disagreements with some of their design principles, there is no doubt that the kits that Dan "Doc Bottlehead" Schmalle sells at www.bottlehead.com provide excellent value for the money and very good sound. You could do a LOT worse and I think taking the bull by the horns and building stuff yourself is an interesting way to go.

-j

 

If you're looking for a cheap SET, the Decware Zen is the way to go. Steve Deckert is losing money on these in an attempt to gain recognition for his (excellent) company. DecwareThey're not who I'd think of first when considering an amp that "rocks," however, I can almost promise you that after hearing the sweetness of the Zen (with the right speakers), you will not regret it.

 

I'll second the Zen recommendation. Have had one only for a month or so and it's my first experience with tubes. Extremely nice sound. Not much power (only about 2 watts or so), but even with 90db speakers it's plenty loud enough for most music. Can be had built for $500, or in kit form for $400.
Ray

 

No problem Drew. It' all related to the subject at hand.

My first choice was the ST 70, but the reason I'm considering the ASL is twofold: my lack of even the most basic electronics knowledge at present, and the fact that it's an intergrated unit--I can't build my own Foreplay as of yet.

Anyway, this is for a small room of 12'x14'. The two speakers I ran across were the Soliloquy SM-2A3 and the Triumph Signature.

I think I'll stick with push-pull for now.

 

There is a list at Decware's website of users that have sucessfully matched their Zen with particular speakers. Speaker Database