ST-70 Series III

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ST-70 Series III

Postby dmfraser » Tue Apr 07, 2015 10:52 am

A new company with a strong reputation in professional music has acquired the Hafler and Dynaco brands and intellectual property. I will not say who as that may be considered advertising.

Our question is:

For an ST-70 Series III amplifier would the preference be for:

1. An amplifier as faithful to the original ST-70 but incorporating the improvements of that have been done to it by the audio community but using no New Old Stock parts. Sorry, no 7199 input. But following the original Pentode-Triode input circuit with feedback.

2. The best possible amplifier that will still use the EL34 output but where the input/driver uses new topologies for what we feel will be better sound quality. We have spoken with people who knew David Hafler and we would basically do what he would have done today if he were around. However, the signal path will still be through tubes.

Either of these made with all new parts will have an MSRP a little north of US$1200. We are not sure yet as we are still waiting for quotes on the transformers from top suppliers.

We ask because there are so many old and rebuilt ST-70 amplifiers out there, that some here have felt that a person who wants the original 1950s sound quality will just buy one of the original or reproductions for a lower price. That a person buying a new unit wants something that is competitive with a current well rated tube amplifier.

Note that the lead engineer on this project received their basic electronics education in the 1960s on tubes and has been involved with the audiophile community for decades. This is not just some rebadging exercise.

Regardless, as a long time DIYer, I would appreciate the input of the DIY community on the approach to take. And your comments do not need to be limited to the ones I have given. For your suggestions, all I ask is that you only recommend tubes that are still in production.
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Re: ST-70 Series III

Postby Geek » Tue Apr 07, 2015 9:51 pm

Well, I know who you are, but the registry still shows Panor as the owner of the Dynaco name (???)

You have some talented personel on hand, these questions should be answered for you ;)

I believe one of your distributors up in the Valley has already given you a few names.

Cheers!
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Re: ST-70 Series III

Postby EWBrown » Wed Apr 08, 2015 8:34 am

EL34s are still abundantly produced by several overseas manufacturers, and probably will continue to be produced for decades to come. The guitar amp industry still consumes the majority of audio power tubes.

In place of the 7199, perhaps using EF86 and ECC82 / 12AU7 (or 6CG7 / 6FQ7) would be a good alternative, both these tubes are currently produced in Europe, Russia and China.
If they want to go to an all triode input / PI topology, then there are numerous circuits using various combinations of the twin triodes
ECC81 / 12AT7, ECC82 / 12AU7, and ECC83 / 12AX7. All of which are still currently produced.

For an all-octal design, then modern versions of 6SN7 and 6SL7 are available.

FWIW, the name "Dynaco" has been taken by a manufacturer of roll-up doors:

https://www.dynacodoor.com/

/ed B [:)
Last edited by EWBrown on Tue May 10, 2016 6:37 pm, edited 1 time in total.
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Re: ST-70 Series III

Postby dcriner » Fri May 08, 2015 8:14 am

FWIW, the name "Dynaco" has been taken by a manufacturer of roll-up doors:

They have a work-around. Buy a Dynaco roll-up door and they with throw in a free ST-70 kit. (lol)

Seriously, I think most people who like ST-70s already have one, and probably aren't in the market for another one. They tend to be an older crowd, children of the '60s, and dying off rather quickly.

P.S. My ST-70 was made from a modern kit, but follows the original design exactly and is a good reference amp. I have two pairs of 7199s (NOS JAN Philips) - one pair installed in the amp and one as a spare. Because the 7199s are lightly driven in an ST-70, I'm set for life.
Last edited by dcriner on Sat May 09, 2015 2:38 pm, edited 1 time in total.
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Re: ST-70 Series III

Postby dcriner » Sat May 09, 2015 10:07 am

A Google search turns up news of Radial Engineering, a Canadian concern, as having bought the Hafler name, but no mention of their buying the Dynaco brand.

Personally, I think that US$1,200+ for a spiffed up ST70 may be a challenging price point.
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Re: ST-70 Series III

Postby Geek » Sat May 09, 2015 4:25 pm

Yep Doug, you hit the nail. They're an hour or so away from me and one of their salespeople have already been in the store.

We requested info, but it has been weeks and nada (???)

Personally, I think that US$1,200+ for a spiffed up ST70 may be a challenging price point.


Even importing something cheap from overseas and slapping on the name, there won't be enough points of margin left for any retailer I know of to want to touch it, methinks (sick)
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Re: ST-70 Series III

Postby dcriner » Sat May 09, 2015 5:04 pm

I wonder if the $1,200+ is with or without tubes? They might have better luck selling it as a kit via the web, but that market already has several internet sellers.

The improvements mentioned, over and above the original ST70, could be readily incorporated inexpensively by a DIYer, if desired, in a used, original ST70 or any of the modern clones (like mine).

I'm still wondering if they just bought the Hafler name or the Dynaco name, too? I don't think it makes much difference, marketing wise. Hafler has been out of the picture for so long, I don't his name on the chassis will result in much spark. Many sellers represent modern ST70 amps and kits as "Dynaco clones," etc., so what would it buy them to "own" the Dynaco name, if indeed they do?
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Re: ST-70 Series III

Postby Geek » Sun May 10, 2015 12:30 am

The ST-70 driver variations have been so fully covered by you, me, Shannon and others that they'd also be hard pressed to do something original enough (if not the classic circuit) to not be hit with a suit.....
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Re: ST-70 Series III

Postby EWBrown » Sun May 10, 2015 1:32 pm

As I recall, a company named Panor bought the Dynaco name a couple decades ago, and sold their (imported from Asia) Solid-State audio and video gear, labeled "Dynaco".

Redistributed from Wikipedia:


In 1991 the Pan Orient Corporation (later Panor Corporation) acquired the Dynaco trademark, and in 1993 began marketing electronic audio components with the Dynaco brand. Panor introduced some new products and reintroduced the Stereo 70 as the Stereo 70 II. Panor/Dynaco's most ambitious stereo tube amplifier was the Stereo 160, a 75wpc, all-tube stereo power amplifier with switchable pentode/triode modes, adjustable tube bias potentiometers, and 6550 output tubes. While Panor owns the Dynaco brand name and trademark, there is no longer any direct connection with the company founded by David Hafler.
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Re: ST-70 Series III

Postby Geek » Sun May 10, 2015 2:34 pm

The database at the public library still shows Panor as the registrant (hence my comment earlier).

They however are using the Dynaco logo on their brochures, BUT unlike the Halfler logo, they claim no (TM) or (R) beside it.

Didn't Dynakit Parts lease the logo rights already? (???)
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Re: ST-70 Series III

Postby EWBrown » Sun May 10, 2015 2:58 pm

The names Dynaco and Dynakit are so old (nearly half a century) that they might be considered as "public domain", just like with old music.

And like New Sensor has done with the Mullard and Tung-Sol brands :/ :| *)
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Re: ST-70 Series III

Postby Geek » Sun May 10, 2015 3:09 pm

I Googled that an application was made for the name, but has yet to be granted. Hence the lack of (TM) or (R)
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Re: ST-70 Series III

Postby dcriner » Sun May 10, 2015 3:31 pm

I googled U.S. trademarks and learned the following. Trademarks must be renewed every 10 years for a fee of $300. Once they expire, they can't be renewed - but I suppose the original TM owner can apply again from scratch or somebody else can swoop in and apply for the expired TM.

Personally, I resent old, well-respected, but now defunct U.S. brands being exploited by Johnny-come-lately organizations, often with Asian or other overseas ties - whether it's legal or not. If somebody wants to advertise or sell a "Dynaco clone," fine - but to brand and label it as Dynaco, No.
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Re: ST-70 Series III

Postby petercapo » Tue May 10, 2016 1:03 pm

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Re: ST-70 Series III

Postby Linn lover » Thu Dec 06, 2018 9:53 pm

I just found this posting on the ST-70 Series III

I am putting this out there: I am a new owner of Dynaco ST 70 Series III from Radial.

I've had it for two days in my home.

Looking to see if others have the same amp, and, if they have tried tube rolling.

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