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Dynaco ST70 Reintroduced!

Broadly similar front end I suppose.

Both ran a voltage amp direct coupled into a split load phase inverter. Williamson used a dual triode and followed it with another dual triode that worked as a gain stage, Laurent used a pentode/triode tube and made all of the voltage swing in one step.

Williamson output stages are class A, Dynaco used AB1.

On some level, everything is related to everything else. I have a Radiotron Designer's Handbook that was published in 1941, and its got some stuff in there that looks awful darn similar to things in amps from the 50s and 60s.
 
They sure look like Hammond transformers. Trademark end bells that don't cusp around the ends of the lam stacks, and the red/brown rubber washers on the ends of the bolts, plus the top stickers, while I can't make out the specific markings, sure look like Hammond stickers. One thing I will give Hammond is their transformers are very consistent and very professionally done. But I think the original winding method on the Dynacos is a notch above the stock Hammonds, so I hope they contracted with Hammond to replicate the original winding. And then wouldn't it be nice if Hammond stocked them for the DIY market!
 
Was just looking on the Dynaco site.
ST-70 series 3 delivered is dropped to $1499 (from $2999 :eek:)
Comments about price earlier in the thread seem to be panning out.....
 
It may be fine. I'm not in the market for another tube amp so someone else will have to be the guinea pig. I have to say i'm not too thrilled with the copy. (i'm referring to written words about it not copying the ST70)
http://dynaco.com/st70.php
 
It may be fine. I'm not in the market for another tube amp so someone else will have to be the guinea pig. I have to say i'm not too thrilled with the copy. (i'm referring to written words about it not copying the ST70)
http://dynaco.com/st70.php
The copy seems to have been written by people who are barely familiar with hifi tube amps, and think that Marshall guitar amps are a good comparison. And they are deliberately not replicating the original A-470 outputs.

Looking at the price of a well-known kit, I take back my earlier comment about pricing.
 
I'll give this guy the benefit of a doubt. This copy is better.
http://dynaco.com/inside-story

I have my doubts that the new output iron is better (not impossible just unlikely) also i think the new iron from triode, dynakits, and tubes4hifi are in fact accurate clones of the original so somebody has the recipe to the secret sauce.
 
Reading that, it appears they settled on a Williamson front end. Not a bad choice, just sort of funny that the Williamson was basically considered the benchmark at the time the ST-70 came out originally but eventually fell out of favor for assorted reasons. Sounds like we've come full circle.
 
When I think of how many items have hit the retail market with 'old' iconic names.....meant to illicit a response that makes you think you're getting a piece of history! Hah!! I don't think there's too much about this amp that's really 'Dynaco' except the name......and even that is just because someone bought that!! Don't get me wrong.... I don't think there's anything 'wrong' with this! Indeed, it's 'brilliant' in some ways!! Triumph motorcycles are back, Dodge brought back the Charger....even though 'Dodge' is really Fiat, and 'Triumph' is mostly made in Thailand....if you buy one, you 'think' you're getting a piece of 'old school' nostalgia. And, perhaps you are.....as there is a bit of 'throw-back' involved in the process of design and manufacture. This new ST-70 is beautiful, and I bet it sounds wonderful, and it's tubes glow just like tubes did back in 1960! If I had a spare $1500 sitting around I'd buy one in a heart beat. Do I believe it would sound better than an 'old, original' ST-70? Well, Yea!! Why? Well.... go read Dave Gillespie's write up here on AK about some of the issues with an ST-70. Given that most any 'stock' ST-70 you'll find today will contain 'some' if not 'all' of those short-comings....and given that this new amp appears to have compensated for much of that.....then, 'yes, it probably does sound better'! BUT....take an 'old' ST-70 and do some of the upgrades to it that are easily performed and reasonably priced.....and now you've got an amp that sounds REALLY great!! In particular, simply 'enhancing' the power supply with a solid-state rectifier and some added capacitance. Then, make sure everything else is 'in spec'...INCLUDING having 2 good driver tubes in the driver stage.....and as Dave supports.....now the 'stock' amp performs extremely well. BUT....that said, take a look at it!! It's old, most are pretty ugly (by comparison), and the WAF just is NOT what this new one is!! At one point when I was deep into my Harley 'customizing' days, I sent a couple of Dynaco Chassis and Cage Cover assemblies to my local HD Chrome shop. I've done spray painting, powder coating, and custom wood covers. In spite of all that, I still think that 'new' amp looks better! AND, THAT is, what I believe, is going to sell it! That, along with the fact that it's a 'good' amp, a 'safe' product, with 'all new' stuff in it, thoughtfully upgraded, and 'guaranteed' by it's manufacturer. Yes, you can still have the 'fun' of building your own Kit.....and I believe MANY will still want to do that. But, as we used to say in the car business: There's an ass for every seat!! I bet they sell every one of these new amps they make.....at least while they're at $1500!! $3K....yea, too much! But I think the $1500 is probably a good price-point. I'm actually 'tempted'....but like NJ..... I'm now at the point where; "if I didn't build it, I'm not listening to it!!". So.....there's my $0.02 worth....FWIW. Tom D.
 
Don't confuse me with the facts:rolleyes:
I'm not sure what you mean by externally commissioned,. He appears to be the lead engineer on the redo.
Also I'll give him a pass on the 5AR4.
I'm reasonably sure Laurent would have went SS had he been making one today.
Honestly , I'd like to see (hear) what they did. Not enough to buy one. At the new price point someone will. Hopefully someone close .
 
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Here’s a Series 2 I purchased hardy used as a demo years ago. It has worked very well over the years. It uses 6GH8’s as drivers. I am currently finishing up a Latino ST70.
 
Yes, sorry for being picky. We should be grateful for this reasonably affordable, new, Canadian- made product. Not everyone can build a kit or refurbish an old unit. :music: It would be really interesting to read a review which compared the sound of this series 3 with refurbished or modified originals using original OPTs.

All I meant (before seeing the lead engineer's article) was that their marketing copy says very little, which is surprising given that the original and its aftermarket upgrades are so well known. I guessed that the lead engineer's write up was commissioned by audioxpress, but maybe it was placed by Radial Engineering..

It's hard to say when an ST70 becomes something else. I got my unit stock, but all that remains of it is the chassis, choke and OPTs. It has a replacement 240v PT from an organ, a 5V4 rectifier tube chosen for its voltage drop with the PT and a VTA board with 12AT7 tubes.
 
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I am new to tubes but after reading the Absolute Sounds article on the ST-70 series 3 and seeing it priced at $1499 I decided to make the plunge pairing it with the Rogue Aduio RP-1 pre amp driving some DQ-10's the sound is wonderful and I'm very happy with it.
 
I would like to see a shootout with this, the ultravalve, and the Latino VTA ST-70. I really wish the VTA had dual rectifiers. This one actually just moved to the top of my list, pending more info
I am new to tubes but after reading the Absolute Sounds article on the ST-70 series 3 and seeing it priced at $1499 I decided to make the plunge pairing it with the Rogue Aduio RP-1 pre amp driving some DQ-10's the sound is wonderful and I'm very happy with it.
What does the switch in the front center do? I guess this only runs in ultralinear mode?
 
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