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ST 70 best sounding version?

Thanks for reading and for your input.  I am thinking of acquiring another tube amp to use in a secondary system and there are so many versions of the Dynaco ST70 available (will Vincent, latino, van alstine, etc).  Has anybody heard several and any feedback would be greatly appreciated....Ralph/Atma too!   Cheers!
pehare
jetter
1,035 posts
 
And while bdp24 is surely right about design flaws, I love mentioning that the ST-70 is the greatest selling amplifier of all time.  I will sheepishly mention that mine are in storage at this time.

Per the Absolute Sound article titled - The Ten Most Significant Amplifiers of All Time - "Along with Avery Fisher’s 500c, David Hafler’s ST-70 put high performance audio in the American home. Introduced in 1959, the ST-70 is the world’s most prolific stand alone amplifier with over 300,000 units manufactured. Amazingly, its clear, three-dimensional sound is comparable to many amplifiers made today."
bdp24's avatar
bdp24
4,908 posts
 

I've had a couple of stock Dynaco ST70's, and there have been some mods or even redesigns which addressed the flaws in that very historically-important and influential amp. Some of Bill Johnson's early ARC designs were variations on those of David Hafler (particularly the SP-3 pre amp)---even at the time of the SP-3/D75/D51, Johnson was selling modded ST70's, and Frank Van Alstine at one time offered an extensive mod which eliminated the ST70's major flaws.

In contrast, Roger Modjeski started with a blank slate for the RM-10, creating a completely new design, not an updated version of a design from the 1950's. Why anyone would want an ST70---old or new, stock or modified---rather than an RM-10 is a mystery to me, especially when an RM-10 can be had for the same price as an ST70. What if a Porsche cost the same as a VW? ;-)

To view the historical significance and number of Dynaco ST70's sold as a reason to consider it worthy of consideration today is akin to doing the same for the Acoustic Research 3a in the field of loudspeakers. Good for it's time, but far surpassed today. I regularly see pairs of AR 3a'a offered on Audiogon at a price that can also buy one a pair of Vandersteen 2c's. Which loudspeaker would you rather own?

twoleftears's avatar
twoleftears
1,457 posts
 
https://www.prosoundnetwork.com/gear-and-technology/dynaco-ships-st-70-series-3-tube-amplifier
jetter
1,035 posts
 
Interesting reading about the RM-10.  Does anyone know what the differences were before the RM-10 and the RM-10 MKII?
jsl1234
32 posts
 
FYI: Bob Latino sells his wares on http://www.tubes4hifi.com/, along with Roy Mottram who sells pre-amp kits and customizations to original Dynaco 70s.

Regarding recitfer tube vs SS, Bob’s amp can run either without issue. In addition, there are a lot more upgrades to the amp beyond the power supply (output transformers, better caps, upgraded chokes, high precision resistors, driver circuit changes, a fully modern tube compliment, upgraded chassis, to name but a few). So IMHO Bob’s amps are really just modeled after the Dynaco ST70--his VTA 120 is a fully modern amp that is much closer to the Rouge Magnum and other modern tube amps that can run KT88s and KT120s (and now even includes an auto-bias board option.....)

Full disclosure--I own Bob’s VTA 120--super product with super support (something you might want to consider). Great supporting community as well.
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