Latest purchase - Dynaco ST-70. PAS-3 Preamp and FM-3 Tuner

[Sal Brisindi]

Last week I mentioned (on another forum
) someone was selling a complete Dynaco ST-70 amp, PAS-3 preamp and FM-3 Stereo tuner all are tube based in case some didn't know. I took a look at them and the tuner was missing its volume knob, the ST-70 amp chassis has oxidized and the preamp looking good from the outside. I did not buy them.

I offered the seller a lower price via email thinking he would not accept it but he did. (I should have gone lower). Anyway today I picked the system up. Here is a photo of the preamp, very clean inside, all original tubes installed with made in West Germany 12AX7's! I'm not going to keep the ST-70 amp, as now I have 5 of them. I might keep the FM-3 tuner. The only reason why I bought the set was for the preamp.

The PAS-3 preamp sounds great, no hum at all, I have to clean the potentiometers as they are a little scratchy. The previous owner built the system about 40 years ago.

The amp has 2 Dynaco labeled Mullard EL34's that test new and a Dynaco label Mullard 5AR4. The EL34's are hitting ebay to help fund my latest acquisition.

Regards,
Sal

[rh2music]

I have a Dynaco FM-1 tuner and Pas-3 plugged into a baldwin 2 channel tube amp. I'm waiting to rebuild my Dynaco MK 3'S But for now my system sound great. Hope yours sounds as good.

[RobertWStephens]

Sounds like you are in for a lot of fun! I have a Dynaco PAS2 and love it. Mine is heavily modified. You can check out Dynaco Doctor if you want to rebuild the phono stage, bypass the tone controls or rebuild the power supply. In the forum it describes how to do it without buying his replacement boards and power supply. They also have a good discussion if you do a search under PAS at AudioKarma. Changing the volume pot(250K log) can also do wonders. Peace. Robert

[EWBrown]

Check the West Germany 12AX7s and see if there is a little "diamond" shape embossed on the base. Those would be Telefunkens.

If it sounds good as is, then I wouldn't replace anything. I like to keep original units around as a "control" against which to compare any upgraded/ modified units, and this sometimes proves out that some of the "fancy" mods and upgrades may not be so hot after all...


One of my better flea market / yard sale "scores" was a PAS-3 which was 100% original for $10, including four nice Telefunkens. The seller just called it "that old tube junk". I had better luck a few years earlier, with a rather messily assembled and somewhat rusty looking PAS-2 at teh local dump's "freebie" table, it also contained 4 Teles. I later replaced the boards with newer aftermarket units from ebay Vintage Electronics, and it sounds a lot better than it looks... The original boards and the wiring / soldering were pretty bad, and I doubt that it had ever much use, because it was so intermittent and noisy on my initial power-on test...
The best part about this particular find was the Scott 310 FM tuner and the Fisher SA-100 that accompanied it Yellow_Light_Colorz_PDT_06
More "old tube junk" , heheheheheh

Unfortunately such finds are becoming increasingly rarer every day...

/ed B

[DerekVa]

I think the proper term for that preamp would be 'minty'. Nice score!

-D

[EWBrown]

It is definitely the cleanest-looking unit that I've ever seen outside of a brand-new unit (and that was around 40 years ago)...

I wouldn't "hot rod" this one, just keep it stock (like a nice clean vintage '57 chevy).

The FM-3 is a decent tuner, if it is in as good shape as this PAS-3, then it should sound really good. These tuners often do need some TLC acter 40 years, but sometimes that "perfect" unit still shows up after all these decades. The "tuning eye" tube for the signal strength meter and "stereo" indicator is about as rare as honest politicians these days, burt everything else is common, easily available stock. The FM-3s power trannie is far larger than is really needed, as the mono version of the tuner (FM-1)
used the same space as for the FM-3's multiplex board, for an EL84 based PP power amp, which was good for around 10 watts of clean mono sound. FWIW, these ampboards are about as rare as the "magic eye" tubes...

/ed B