Dynaco St-70

[Doug J Keaton]

Hi All. I'm new to the forum.

I've had a pair of rt1000's for a couple of years and now I want to buy a Dynaco St-70. For some reason I decided to get obsessed with tube equipment and that's the one I want/can afford.

Will this amp be a good match for the speakers? I'm at work now, but from what I recall they are 200 watt speakers with a sub-woofer. Is 35 watts per channel too little to power?

Also, as far as wiring goes I obviously can't use a sub-woofer connection from the amp so do I just go with a normal hook up for the speakers?

[steveinaz]

Depends on how loud you like your music. 35 watts is no push-over, just be careful about pushing the amp too hard.

Let some of the experts with this particular speaker/knowledge of this amp chime in though.

[Tour2ma]

With the 1000's powered sub handling the load below 80Hz, I think a ST-70 is a good place to start, if you're set on going tube amp.

Alternative to consider would be a tube pre-amp with a SS amp behind it.

Welcome to the Club...

[TroyD]

I'd opt for the tube pre/SS amp option as well

BDT

[organ]

Hi Doug,
Welcome to the forum.

You will be amazed by the RT/Dyna combo. I used to have a pair of RT800i that I ran with my ST70 and the sound was just amazing. I would take that system over my LSi/NAD combo any day.

If you're not planning to annoy your neighbors, the Dyna should provide enough power.

Make sure the amp have been tested by a technician and is working right. Dynacos are old and a lot of ST70 need plenty of TLC. If you decide to get the Dynaco, forget the EL34 output tubes. Get KT66 instead.

Maurice

[BlueMDPicker]

If you decide to get the Dynaco, forget the EL34 output tubes. Get KT66 instead.

Won't he have to do the triode operation mods to run KT66?

[organ]

Hi Mike,
No need to do the triode mod for KT66. My 66 are running in ultralinear.

Actually, I did the triode mod last week to see how they perform. Went back to ultralinear in two days.

[Doug J Keaton]

I went ahead and bought the Dynaco. I will also be buying a Scott 130 preamp to match. I hope it all works out.

As far as the sub-woofer goes do I just run a normal old set up? Before I had a sub-woofer out channel - that is obviously not the case with the Dynaco.

[organ]

Kick ass! Congrats on your purchase. The ST-70 is really something special. I love mine very much and will probably be my last amp.

A few questions... What tubes did you get with it? If it's the original "Dynaco" labeled tubes or anything that says Mullard, take them out and put them in a safe place and replace with current production. Those old Mullard tubes are worth a lot of $$$.

Do you have a multimeter? You're going to need one to bias the amp.

Is the amp stock or modded?

Here's a great site with a ton of info that will come in handy to all ST-70 owners www.dynaco-doctor.com

I've done a lot of work on my amp. Feel free to PM me if you have any questions.

Maurice

[Tour2ma]

I think Maurice is more excited than Doug...

Congrats, Doug. Assuming your Sub has a built in cross-over, just feed it via the speaker level inputs, then carry on from it to your mains.

[Doug J Keaton]

It's the audio research modification and in absolutely in great shape. It's the older model with the brown shell - so I think it has the cloth lead transformers I read so much about. I'm having the inputs replaced with some gold plated stuff (It was recommended), but everything else should be about good to go.

The amp is at a repair shop now being looked over. Is there anything I should ask them to fix or update in particular?

I don't know about the tubes, but I'll check that out for sure.

Any opinions on the Scott 130 preamp?