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dynaco [message #8296] Tue, 29 June 2004 14:54 Go to next message
tube newbie is currently offline  tube newbie
Messages: 2
Registered: May 2009
Esquire
what dynaco is best? what price is fair on ebay? are they as good as new tube amps made these days?

Re: dynaco [message #8297 is a reply to message #8296] Tue, 29 June 2004 20:01 Go to previous messageGo to next message
metasonix is currently offline  metasonix
Messages: 103
Registered: May 2009
Viscount
Any Dynaco is good. If you just need a small amp for low-power listening, the SCA-35 or ST-35 are great. If you need more power, look for a decent ST-70 (they got loved a lot, so finding one in good shape is difficult). And get Mark IIIs if an ST-70 isn't enough.

BEWARE of units showing rust--it really ate those chassis quickly, and rust is usually a sign of abuse or neglect. Such amps almost always need new filter capacitors, and often new power tubes. Once rebuilt they are as good as new amplifiers in performance. Ebay can be a dangerous place to look for old tube amps, so be aware of this. If you win a bid, tell the owner that you won't accept an amp that has a bad transformer, lots of rust, or other major problems. If they act squirrely, CANCEL the bid.

Re: dynaco [message #8298 is a reply to message #8297] Tue, 29 June 2004 22:45 Go to previous messageGo to next message
tube newbie is currently offline  tube newbie
Messages: 2
Registered: May 2009
Esquire
thank you for your advice. are the transformers available? expensive or impossible to replace?

Re: dynaco [message #8299 is a reply to message #8296] Wed, 30 June 2004 10:31 Go to previous messageGo to next message
akhilesh is currently offline  akhilesh
Messages: 1275
Registered: May 2009
Illuminati (3rd Degree)
IMHO, dynaco amps, are useful if you are looking for using with speakers with normal efficiencies (85-89 db) if you have efficient speakers (90 db +) then there are plenty of other choices....for examle the stoekit from heart audio, that i am currently reviewing, that sound pretty good.
If you do buy a dynaco,spend the $600 and buy one that has been done up completely, otherwise you may be entering a never ending cycle of buzz and hum......
just my 2 cents
-akhilesh

Re: Raining on the Dynaco parade [message #8300 is a reply to message #8296] Wed, 30 June 2004 16:16 Go to previous messageGo to next message
BillEpstein is currently offline  BillEpstein
Messages: 886
Registered: May 2009
Illuminati (2nd Degree)
All the while I was building my ELLA amp, I was listening to A restored ST-70 courtesy of Speakerman. Over about a 2 week period I became very familiar with it's sound. Once I hooked up ELLA, it was obvious that the Dynaco lacked the detail up and down the frequency range of ELLA and had less low end weight. It was warmer sounding but not as "balanced". We later had a shoot-out at Ron's place and the Wave 8's also fell well short.
2 of the most over-rated amps out there, I would say.

Re: dynaco [message #8301 is a reply to message #8299] Wed, 30 June 2004 18:05 Go to previous messageGo to next message
hurdy_gurdyman is currently offline  hurdy_gurdyman
Messages: 416
Registered: May 2009
Illuminati (1st Degree)
Sounds like good advice for ANY respected vintage amp.

Dave

Re: dynaco [message #8302 is a reply to message #8298] Thu, 01 July 2004 00:01 Go to previous messageGo to next message
metasonix is currently offline  metasonix
Messages: 103
Registered: May 2009
Viscount
> are the transformers available? expensive or impossible to replace?

The power trans on the ST-70 runs very hot and fails occasionally.
And in 1990 I counted 6 different Stereo-70 driver boards on the market. Most of those companies have since dropped out of sight.

Magnequest makes some Dyna replacement transformers. Rather costly at ~$150 each.

Curcio Audio still makes new Stereo-70 driver boards and repair kits for Dynas. Curcio now calls himself Dynaco Doctor (http://www.dynaco-doctor.com/).

After some looking around, I found that Triode Electronics (Ned Carlson) now carries new driver boards and transformers for Dynas. Their prices are more reasonable too.
http://store.yahoo.com/triodeel/dynacoupgrades.html
(I should warn you that Ned is very opinionated and also friendly with some of the more antisocial elements on Audio Asylum and rec.audio.tubes.)

Welborne Labs has new driver boards for ST-70s and Mark IIIs.
http://www.welbornelabs.com/st70.htm
There's also the Van Alstine stuff.
http://www.avahifi.com/root/equipment/dyna_rebuilds.htm

I should note that if you replace one bad output trans on an old Dyna stereo amp with one of these new replacements, the channel with the new trans might sound slightly different from the channel with the old trans. Usually unavoidable. You could always try a vintage hifi repairer like VTV (which I do occasional work for). VTV actually has a stockpile of genuine old Dyna transformers. (Not cheap!)

If you go looking on search engines or other websites for Dyna info, be aware that they tend to be out of date and / or contain errors or misinformation. For example:
http://www.tnt-audio.com/ampli/dynaco1e.html
It's a pretty good article, though I take great exception to his statement that Dyna output transformers were "among the best ever made". Not really true, and you can even get new ones (Plitrons, for one) that make Dyna transformers look sick. Plus, that article is from 1998, and some of the advice is outdated.


indeed, dave! (nt) [message #8303 is a reply to message #8301] Thu, 01 July 2004 01:30 Go to previous messageGo to next message
akhilesh is currently offline  akhilesh
Messages: 1275
Registered: May 2009
Illuminati (3rd Degree)
nt

Excellent advice Metasonix! [message #8304 is a reply to message #8302] Thu, 01 July 2004 01:32 Go to previous messageGo to next message
akhilesh is currently offline  akhilesh
Messages: 1275
Registered: May 2009
Illuminati (3rd Degree)
Great advice! My impression after reading metasonix's post is to wonder, why bother with the dynaco? There are many other amps available today that are new.
thanx
-akhilesh

Re: dynaco [message #8305 is a reply to message #8302] Thu, 01 July 2004 06:54 Go to previous message
Manualblock is currently offline  Manualblock
Messages: 4973
Registered: May 2009
Illuminati (13th Degree)
The stereo 70 was an excellent amp when they went for 150$. I have one and have replaced the:
Driver Board(sound values)125$
All tube sockets w/ceramic 80$
The power supply w/Curcio's upgrade90$
power supply choke 20$
various jacks and resistors and caps 50$
All in all it now is a very good sounding amp but for approx. 500$
Now I see them going for 400$ just for the amp so do the math. The stock units are not so fine sounding but you can replace certain caps and other parts to sqeak by but I would look elswhere.
I use it when I need power the amp drives the PI 4's to very respectable levels. Good for backyard parties!

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