[vtst70guy]

Hi all,

I am new to this and just purchased a rebuilt St-70 from a guy in South Dakota who has rebuilt a ton of them.  Right out of the gate, I found that the preamp I had purchased (a Schiit Saga) did not seem up to the task of creating any real volume with the amp.  In fact, I am returning it and I have purchased a PAT-3 to replace it.  (Should arrive soon.)

I guess my question is this, I am replacing a solid state Kenwood KR-6600 with this dyanaco and am now worried that is till not be loud enough even with the new preamp.  Can someone attest to how loud these are when properly set up? I am not looking to break window or anything, but I like my music pretty loud.  Also, I am running a set of Heathkit 1373 speakers.

Any advice would be great.  Thanks!  Liam

[FullRangeMan]

Welcome 
Check the output preamp voltage and impedance with the power amp sensitivity and impedance, impedance ratio must be at least 10x.

[mick wolfe]

I drive a Latino ST 70 with a Schitt Saga. No issues whatsoever with plenty of gain. I think there's an issue in this aside from the Saga.  Maybe call the amp builder ( I assume Will Vincent ? ) and explain the problem.

[rotarius]

What sources do you use?  How efficient are the speakers? The Saga adds no gain to the mix.  You should ask the seller if he used a low gain board or not. 

[vtst70guy]

Thanks, guys!  I went through about every permutation of hook ups I could.  It turns out the phono hooked through the preamp and then through the amp resulted in a whisper of sound.  Same when I put the phono direct into the amp.  (Phono worked fine when plugged back in to my Kenwood.)  Next I put my iPhone through preamp and then amp and then just through the amp.  Louder, but not as loud as I would like.

Not sure how efficient the speakers are. 

I called the builder, a guy named Bob Arshem, and he and I went through some troubleshooting and we came to the conclusion that something is up with the Schitt (which I got used).

I am going to figure out how to measure impedance tomorrow.

I appreciate all your ideas.  thank you.

[Phil A]

Welcome - you could always go to a local store and take the amp (and if the speakers are small enough, you can take those too)  and audition what they have and look at sources like - https://www.stereophile.com/category/tube-preamp-reviews   to ascertain what gain particular preamps have before auditioning.  That should at least give some exposure as to limitations.  If there are local audiophile clubs where you are you could always join and see what others use and maybe get local members to bring over different preamps.

[FullRangeMan]

Not sure how efficient the speakers are.

If the speaker are low efficiency as 83-85dB there is no prob, just inefficient speakers.

[rotarius]

Your iPhone output is around 1V probably, not enough.  Try to connect a CD or DVD player and see if all is well, I suspect it will be.  In that case, you need a preamp with gain.

[vtst70guy]

Update:

Miraculously, the dynaco preamp I ordered yesterday arrived this afternoon, somehow.  I hooked it up with my phono and same problem.  I then set the ground from the phono to the back of the preamp and wham, good volume.

I am know suspecting I sent away a perfectly good Saga preamp, but at least everything seems to be functioning properly and I can settle in to enjoying this stuff for a minute.  Thanks for all your suggestions.  see you around here soon!

[JerryM]

Having a "new to you" ST-70 and all, you'd be remiss not to check out Frank Van Alstine's AC Circle here within, or especially his Audio Basics Newsletter Archives.

Frank is the Granddaddy of ST-70's. 

Have fun,

Jerry

[bladesmith]

Welcome...

Get some efficient speakers..
that's the answer.

 

[Delta77]

Just a quick recommendation with very little thought,
Would be to look into something like a used Wyred 4 Sound preamp/Dac and some Omega Speakers..
Also sounds like a Phono preamp may be in order. Some preamps have them (added Cost), most don't..

[mick wolfe]

Welcome...

Get some efficient speakers..
that's the answer.

 :popcorn

 

Absolutely... a more efficient speaker with a tube friendly impedance curve will certainly bring a lot more magic out of the ST 70. I'd probably e-mail Schitt and tell them to send that Saga back as well. That's a very nice little versatile pre-amp.