VTA ST-70 Review (Stereo Tube Amplifier)

[wwenze]

Can I hook this to a microwave oven and send 36 bytes of data

What else would you buy antique electronics for

 

[H-713]

Can I hook this to a microwave oven and send 36 bytes of data

What else would you buy antique electronics for

The fact that they're interesting? I mean, did you look at the thing?

New doesn't inherently mean better. There are usually (though not always) improvements in some regards, usually at the cost of performance in others. Sometimes the tradeoffs do not make sense - for example, you can use an arbitrary waveform generator as a pulse generator, but boy is it a pain.

Tubes still have their place in the world - they can handle very high voltages and are generally unaffected by some of the things that annihilate semiconductor devices.

As for tube amps? Because they're fun. Same reason people buy old cars. If you view your stereo as an appliance, there's no point (and if that's the case, why are you here?) If you view your stereo as a project, there's plenty of reason. I for one find old tube amps to be beautiful, and they're lots of fun to play with.

 

[Billy Budapest]

Convinced yet that it'd be a good wager??

Not at all. It would be a terrible risk, whereas with a $4500 payment for the genuine article, you are getting a reliable amplifier—and one that measures respectably for a tube amp.

 

[H-713]

Not at all. It would be a terrible risk, whereas with a $4500 payment for the genuine article, you are getting a reliable amplifier—and one that measures respectably for a tube amp.

And also one with known resale value.

 

[MattHooper]

Another excellent review.

I was launched in to the audio hobby upon listening to my friend's system: Quad ESL 63s powered by the Dynaco ST70 amp.
The sound was magical (mainly because it was my first extended listen to electrostatics). I can't remember if he ever used a solid state amp with the Quads as well.

(I later bought Quad 63s and a Conrad Johnson MV55 tube amp and really enjoyed that set up).

 

[xarkkon]

Some eye candy about the Dyna ST-70.

dumb question, what's with the RCA splitters?

 

[Doodski]

dumb question, what's with the RCA splitters?

I wish I knew what they are doing like that. Perhaps running 2 sources into one amp? That seems like a bad idea.

 

[Labjr]

dumb question, what's with the RCA splitters?

Are those hydraulic hoses!

 

[Midwest Blade]

"But how does it sound."

...just kidding!

Thanks again for another revealing test and review. When this one was put up on line the results were almost predictable. Is it only my impression that decently good gear is actually harder to come by than I thought?

 

[anmpr1]

The one thing that really stands out to me is how dynamic the midrange is using my amp is on my upgraded Forte II's. I've never heard a SS amp do this. In my limited experience, of course.

I don't doubt that, subjectively. Recent anecdote: when I replaced my Mk IVs (and an 'updated' PAS look a like) with the AHB2/DAC3HGC (and external phono stage) I too experienced something like that, and frankly thought the Benchmark combo didn't sound as good as the Dyna.

But I know that it is easy to fool oneself, and the next day I fired up the Benchmark, and that combo sounded better, with 'tighter' mids and lows, and generally more 'strength' (if any of that makes any sense at all). How much is just imagination? When you go to the ball park, the dogs always taste better than those you water boil at home, on your stove.

Now, in a DBT could I tell the difference? Levels matched, and brands hidden? Possibly, with a 60 year old tube design v a SOA (in the distortion department) SS amp. Possibly, differences could be distinguished. At least it wouldn't surprise me. I'm not going to worry about it, and in any case, I am happy I have both.

I admit that for me, as a hobbyist, it doesn't really matter. For ASR, however, the idea (as I understand it) is to decide the best engineering given what is out there, and given what one has to work with. But there has to be some grounding. Some overriding perspective to it.

I've always thought that comparing tube to SS makes little sense. It did in 1960, but not today. We know (or should know) the results before we even start. I mean, when we take higher math we don't have to go back, on the first day of class, and prove the Distributive Property of multiplication and division. It's one of a foundation that we know and accept. Likewise, we 'know' that anything you can do with a tube, you can do better (electrically) with a SS circuit. It's just the way it is.

Before ASR there was Peter Aczel (in his second version of his Audio Critic). Peter refused to review tube gear, or take it seriously, because he was looking for 'the best with the the less', as it were. His analogy: If I was looking for the fastest land animal I'd want to investigate the thoroughbred race horse, and not the donkey. I'd certainly consider the greyhound or the Afghan hound, but I wouldn't mess with a Pug. Maybe check out a cheetah or jaguar, but probably not your overfed lap cat. Of course that doesn't mean a donkey can't pull a cart as well as a racehorse, or that Snoopy or Garfield can't calm your nerves in a way a cheetah or high strung hound probably won't be capable of.

 

[don'ttrustauthority]

I think within the DIY community, many mods are based on assumptions and beliefs.

You think? LOL

 

[Cougar]

I have the Latino VTA-120 and this is my favorite amp. I use Class D Crown XLS 1502 and EDGE M8 amps and I still come back to the VTA-120. The circuit design is all new like the VTA-70 and only share with Dynaco is their looks. Even the Transformers are bigger and better built. My VTA-120 pushes my Clearfield Continental 87db 4ohm speakers to loud levels with no problem no sign of any stress and that is using a GZ37 Rectifier Tube. This amp is very quiet and I hear no noise or hiss at all. I'm glad I bought and built this amp.

 

[don'ttrustauthority]

and we say tube amps sound rich due to 2nd order harmonics.

They say acetaminophen and ibuprofen are safe.

 

[pseudoid]

Nelson Pass' H2 - DIY Harmonics Generator are for those who yearn nostalgically for the olden tube days!

 

[anmpr1]

Not sure if this has been posted. High Fidelity magazine, December 1959. Before Gillian Gersh went to Stereo Review.

 

[B&WTube]

This is where ASR needs to evolve. I have a umber of issues with this.
First, is the poll- If you have experienced a device firsthand- you shouldn’t get a vote.
Second, measurements need to evolve to measure some of the immersive qualities. I don’t know how this needs to be done but it does. Audio science should work towards utility that is both technically good and practically good. For an example, right now the Aiyima A07 is unbelievable value, and blows the VTA70 out of the water on theses test. However, as an owner of both they are no where in the same league, and I can’t imagine anyone picking the Aiyima over the VTA, blind on anything except bass- the tubes even with SS rectifiers still aren’t close on the lows. However, the VTA brings the artist into the room far better, and it is a much more real feeling experience. I am not advocating that this is Benchmark levels at all- but it is very a very good experience that pretty much everyone who heard them would agree on.
So, how do we measure these aspects and how they appeal to people?

 

[SIY]

So, how do we measure these aspects and how they appeal to people?

Step 1: Confirm via ears-only tests that these aspects actually audibly exist. Then measurement becomes straightforward.

 

[anmpr1]

This is where ASR needs to evolve. I have a umber of issues with this.

My view is that as long as it's all kept in perspective, everything is fine. To make a kind of comparison, no one expects a 1959 VW Beetle to compete in any way with a 2022 GTI. But you can do a lot of things with a 1959 Bug that you can't do with a new GTI.

With a manual, and some parts off the Internet, along with a few basic tools, you can work on it yourself. If something breaks you can fix it on a weekend. The average cat can't do that with a new GTI.

You can hot rod a Beetle. Turn it into a dune buggy, and have a ton of fun. While you can have some fun driving a new GTI, it is doubtful you can turn one in to a dune buggy, in your garage, on your summer vacation. Or if you could, you wouldn't.

You can drive a Beetle around town and people will admire you. Or think you are crazy. If you drive around town in a GTI, no one will care.

So you just have to keep this old stuff in perspective.

 

[pseudoid]

... 1959 VW Beetle to compete in any way with a 2022 GTI

Why couldn't you pick the Vette or the Porsche for your comparison...

 

[amirm]

First, is the poll- If you have experienced a device firsthand- you shouldn’t get a vote.

The vote is membership reflection of the data as presented, plus anything else they would consider (e.g. cost).