My Dynaco ST-70 Has Ruined My Other Amps

[David_NC]

My Dynaco ST-70 has ruined my other amps... at least in terms of my listening enjoyment. I've used a QSC USA 900 and later a Parasound HCA-1000A as my main amps with a pair of ADS M12 towers. I've enjoyed these speakers, and the rest of my setup, quite a bit.
Recently, I put my refurbed ST-70 in the mix in place of the Parasound. It was good, and I really liked the sound of it. After getting comfortable with it, I swapped the original tubes back in - Tung-Sol 7199's, Dynaco 5AR4, and Sylvania / Philips 6CA7's. I've listened to that combo for a couple weeks now, but a few days ago, I decided to go back to the Parasound due to the fact that it's a pain to use the Dynaco; it won't physically fit into my setup properly. That lasted for two days; the qualities that had really impressed me were gone. Many / most of the tracks I played were lacking something, and, in many cases, sounded sort of lifeless... not bad, but not as lively. Dynaco to the rescue! I swapped the Dynaco back in, and all is well.
Honestly, I did not think this combo of speakers and 35 watt amp would sound so good. The M12's are power whores at 87dB efficiency and really shine with lots of power. The previous amps I used with them are rated at 440 and 200 WPC at the M12's 4 Ohms. My current listening setup has me positioned closer to them than is typical for speakers their size, but I can't change that at present. The worst I can see is that I'd need more power for them in a larger room, though crossing them over at 55Hz to a powered sub undoubtedly helps with that. Still, at this point in time, in this situation, the ST-70 and M12's are a great combo. I'm curious if others have tried any of the larger ADS models, in particular the towers, with a mid-powered tube amp like the ST-70 and what experiences they had.

 

[tonyg88]

its the tooobs man

 

[adnick]

Have a Latino “upgraded” ST 70 that I use with some Infinity RSMs at 4ohm, and they sound just as good as with my Threshold, and that’s saying a lot!

Have discovered another amazing tube item...rebuilt my PAS 3 with the top end Erhard Audio PAS components, dual power supplies, tone control, and phono upgrade, (7 tubes in all now) and wow, it was like a new listening experience.


Paired with the ST 70 it’s now my favorite system...

Regards,
Andy

 

[nj pheonix]

There is a reason there were more of those sold over 40+ years than any other amplifier.
Simple well designed circuit and excellent transformers.

 

[Akustic]

Bi-amp them with tubes on the top end and a serious SS amp on the bottom ..

Minor and cheap (like $60 labor and $10 parts) modification to the speakers if they don't already have two sets of binding posts ..just tap into the crossover between the woofers and the midrange.
You have the amps and ADS's almost all have that smooth accurate sound that I call the ADS house sound .. they're great classic speakers in need of amplification.
Use the Parasound on the bottom (woofers) and the Dynaco on everything but the woofers..
You'll be surprised what they can sound like with plenty of both kinds of power..

You have everything that you need for great sound ..
The Parasound will keep the bass strong and tight, but the speakers will sound like they do through the Dynaco.. just with tighter more plentiful bass ( and probably improved dynamics across the spectrum) ... easy to try a more powerful bass amp down the road too ..

 

[jblnut]

What akustic said...I did this for a decade on JBL 250's and it all started when a friend let me borrow his ST70. Just wait until you hear it coupled with big SS power on the woofer.

Jblnut

 

[PPstereo]

I have allot of different tube amps, solid state amps, speakers including ads 810 and many jbl speakers large and small so on....

In general I've found tube amps just sound great on most of all of em, so long as i was listening within the power limits of the tube amp. And yeah, tube amps sound as if they are more powerful than their watt ratings. But that simply isnt true. Imo they demonstrate how when listening below VERY loud levels we are often within the 15 watts or less realm most of the time. And tube amps often have a euphoric kind of sound that is often very forgiving.

With that said I have many ss high power amps that sound great too. But imo ss amps can "integrate" into a setup with a bit more fuss to the whole process. Whereas when one sticks a tube amp into the mix, theres often better synergy right off the bat.

Again these are all generalizations on my part. And clearly theres more to it all.

But overall when not playing at really loud levels it's real easy to love the sound of a well made tube amp. Just when I'm alone with no one to disturb and I want to jam some rock or whatever at LOUD levels, I not fortunate enough to own a 300 watt tube amp

 

[David_NC]

Bi-amp them with tubes on the top end and a serious SS amp on the bottom ..

Minor and cheap (like $60 labor and $10 parts) modification to the speakers if they don't already have two sets of binding posts ..just tap into the crossover between the woofers and the midrange.
You have the amps and ADS's almost all have that smooth accurate sound that I call the ADS house sound .. they're great classic speakers in need of amplification.
Use the Parasound on the bottom (woofers) and the Dynaco on everything but the woofers..
You'll be surprised what they can sound like with plenty of both kinds of power..

You have everything that you need for great sound ..
The Parasound will keep the bass strong and tight, but the speakers will sound like they do through the Dynaco.. just with tighter more plentiful bass ( and probably improved dynamics across the spectrum) ... easy to try a more powerful bass amp down the road too ..

Yeah, I'm thinking about it. Ideally, I'd like to find the input panel from a pair of M12/90's (or L1290's) that had the biamp setup from the factory to keep that factory look. For now, with the speakers so close to my listening position, I'm OK with the ST-70 as-is. It'll be much more of a priority when things change in the next year with different living situation.

 

[Akustic]

Yeah, I'm thinking about it. Ideally, I'd like to find the input panel from a pair of M12/90's (or L1290's) that had the biamp setup from the factory to keep that factory look. For now, with the speakers so close to my listening position, I'm OK with the ST-70 as-is. It'll be much more of a priority when things change in the next year with different living situation.

Sounds like you're happy as is .. but ya might be surprised ..
You can certainly make it look good with these ..

https://www.parts-express.com/cat/terminal-plates-cups/321

 

[David_NC]

Sounds like you're happy as is .. but ya might be surprised ..
You can certainly make it look good with these ..

https://www.parts-express.com/cat/terminal-plates-cups/321

Oh I have no doubt it'd improve them. I've gotta figure out how to use the ST-70 in my current setup some way other than on a small plastic tote sitting in front of the shelf! I don't have enough vertical clearance in the shelf unit for it at the moment. I've found a couple ADS input boards on eBay and will keep my eye out for some that are more reasonably priced.

 

[Lavane]

Bi-amp them with tubes on the top end and a serious SS amp on the bottom ..

Minor and cheap (like $60 labor and $10 parts) modification to the speakers if they don't already have two sets of binding posts ..just tap into the crossover between the woofers and the midrange.
You have the amps and ADS's almost all have that smooth accurate sound that I call the ADS house sound .. they're great classic speakers in need of amplification.
Use the Parasound on the bottom (woofers) and the Dynaco on everything but the woofers..
You'll be surprised what they can sound like with plenty of both kinds of power..

You have everything that you need for great sound ..
The Parasound will keep the bass strong and tight, but the speakers will sound like they do through the Dynaco.. just with tighter more plentiful bass ( and probably improved dynamics across the spectrum) ... easy to try a more powerful bass amp down the road too ..

One of the best systems I ever heard was a restored ST-70 played through some amazing speakers designed my an acoustic engineer. A Sub built by the same engineer was used for the low end. The main speakers were just plain weird looking maybe 27"high and maybe 4 or 5 inches deep and hung on the wall. There were some strange custom drivers built into the "thick picture frame" looking cabinets. The sub was built 8 to a big granite cube.
After that I always kept the ST-70 in mind.

 

[Lavane]

My Dynaco ST-70 has ruined my other amps... at least in terms of my listening enjoyment. I've used a QSC USA 900 and later a Parasound HCA-1000A as my main amps with a pair of ADS M12 towers. I've enjoyed these speakers, and the rest of my setup, quite a bit.
Recently, I put my refurbed ST-70 in the mix in place of the Parasound. It was good, and I really liked the sound of it. After getting comfortable with it, I swapped the original tubes back in - Tung-Sol 7199's, Dynaco 5AR4, and Sylvania / Philips 6CA7's. I've listened to that combo for a couple weeks now, but a few days ago, I decided to go back to the Parasound due to the fact that it's a pain to use the Dynaco; it won't physically fit into my setup properly. That lasted for two days; the qualities that had really impressed me were gone. Many / most of the tracks I played were lacking something, and, in many cases, sounded sort of lifeless... not bad, but not as lively. Dynaco to the rescue! I swapped the Dynaco back in, and all is well.
Honestly, I did not think this combo of speakers and 35 watt amp would sound so good. The M12's are power whores at 87dB efficiency and really shine with lots of power. The previous amps I used with them are rated at 440 and 200 WPC at the M12's 4 Ohms. My current listening setup has me positioned closer to them than is typical for speakers their size, but I can't change that at present. The worst I can see is that I'd need more power for them in a larger room, though crossing them over at 55Hz to a powered sub undoubtedly helps with that. Still, at this point in time, in this situation, the ST-70 and M12's are a great combo. I'm curious if others have tried any of the larger ADS models, in particular the towers, with a mid-powered tube amp like the ST-70 and what experiences they had.

I have several restored early to mid 70's Marantz separates and integrated amps. But after building a VTA ST-70 they haven't gotten much use. Now just setup around my Bench. I have rotated the SS gear in from time to time, but always came back to the ST-70. I only have one amp that I've built that I like almost as much. But it's only 5.5wpc and I need to get more efficient speakers for it. There must be a reason the ST-70 is well liked. It never did go completely out of production with people like Bob Latino keeping them alive.

 

[Lavane]

Have a Latino “upgraded” ST 70 that I use with some Infinity RSMs at 4ohm, and they sound just as good as with my Threshold, and that’s saying a lot!

Have discovered another amazing tube item...rebuilt my PAS 3 with the top end Erhard Audio PAS components, dual power supplies, tone control, and phono upgrade, (7 tubes in all now) and wow, it was like a new listening experience.


Paired with the ST 70 it’s now my favorite system...

Regards,
Andy

Did you use the older 12au7 line stage board or the new 12ax7 board? I tried both and both sounded really good. Erhard sent me one of the first 12ax7 boards to try out and see how I liked it. With that power supply the line stage is dead quiet.

 

[adnick]

Here’s a picture of mine close to completion, includes tone control, and decided to keep it analog with the rectifier tube....(new board)

Run my ST 70 in Pentode mode about 30% of the time, bu think that’s gonna go up considerably with the “new” Erhard PAS....

 

[David_NC]

I have several restored early to mid 70's Marantz separates and integrated amps. But after building a VTA ST-70 they haven't gotten much use. Now just setup around my Bench. I have rotated the SS gear in from time to time, but always came back to the ST-70. I only have one amp that I've built that I like almost as much. But it's only 5.5wpc and I need to get more efficient speakers for it. There must be a reason the ST-70 is well liked. It never did go completely out of production with people like Bob Latino keeping them alive.

I have a couple 1060's that I want to try as a preamp for the ST-70. I generally use it with a Mac C31v, which I doubt the 1060 will beat, but it'll be fun to compare the 1060's internal amp to the ST-70. It's one of my favorite vintage integrateds.

 

[Lavane]

I have a couple 1060's that I want to try as a preamp for the ST-70. I generally use it with a Mac C31v, which I doubt the 1060 will beat, but it'll be fun to compare the 1060's internal amp to the ST-70. It's one of my favorite vintage integrateds.

I restored two 1060's. I gave one to my son. I used mine as a preamp for a model 140 power amp. It's a nice combo. Now that I think I of it I don't think I've tried my 1060 with the ST70. I did try a model 33 and 3200 preamp along with a 3600 pre. The 1060 should sound good, but probably not as good as the C31v. For the second from the bottom offering by Marantz the 1060 is pretty well designed and liked.

 

[Nixxuz]

Bi-amp them with tubes on the top end and a serious SS amp on the bottom ..

Minor and cheap (like $60 labor and $10 parts) modification to the speakers if they don't already have two sets of binding posts ..just tap into the crossover between the woofers and the midrange.
You have the amps and ADS's almost all have that smooth accurate sound that I call the ADS house sound .. they're great classic speakers in need of amplification.
Use the Parasound on the bottom (woofers) and the Dynaco on everything but the woofers..
You'll be surprised what they can sound like with plenty of both kinds of power..

You have everything that you need for great sound ..
The Parasound will keep the bass strong and tight, but the speakers will sound like they do through the Dynaco.. just with tighter more plentiful bass ( and probably improved dynamics across the spectrum) ... easy to try a more powerful bass amp down the road too ..

Now I'm paraphrasing, and there might be some fundamentals I'm missing, but I've heard that my tube amp, (Yaqin MC-13S), is very close to the ST-70 in design.
In any case, I'm doing a variation on what you are talking about. signal to DAC to preamp, then to a MiniDSP 2X4. One set of signals, crossed over with the MiniDSP, goes to the Yaqin powering a pair of Lii Audio Fast 10S FR 10"s. The other set goes to a Crown XLS1000, and out to a pair of Dayton Ultimax 10" subs. Built both drivers into a common baffle with the Ultimax sitting in a slotted enclosure tuned to 27hz. Bad pic and plenty of finish work to be done, but they sound great. Hybrid setups are awesome.

 

[sKiZo]

I know where you're at here ... the Dynaco design certainly had something going for it that's easy to get addicted to.

Still does, matter of fact. Picked up a Latino ST120 kit as I'd always wanted one, and my big ol' McIntosh amp needed service desperately. Been several years now, and haven't seen any desperate need to repair that SS amp after all. ;-}

 

[David_NC]

I know where you're at here ... the Dynaco design certainly had something going for it that's easy to get addicted to.

Still does, matter of fact. Picked up a Latino ST120 kit as I'd always wanted one, and my big ol' McIntosh amp needed service desperately. Been several years now, and haven't seen any desperate need to repair that SS amp after all. ;-}

Yeah I keep eyeing the ST120 and M125 kits! Not now, but soon!

 

[lokerola]

Yea, I still have my ST70 running in the living room - sounding great this morning. One day I'd like to try a tube preamp with it.