Don Sachs SP14 Tube Preamp Review

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Pryso

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #540 on: 1 Feb 2019, 06:07 pm »
This morning I found Don just posted this on Audiogon.  I trust he won't mind my relaying it here.  Now I need to think about the upgrade. :duh:

Hi All,
A customer pointed out this thread to me.   I will just say that I have improved the line stage by about 10-15% in the past few months.   I have gone to a different output cap, a Polish made Duelund copy that is just mesmerizingly good.   Also, about a month ago I managed to adapt the preamp so it can take a 6BY5 rectifier and still use the 6X5GT or Bendix that it always could.  The 6BY5 adds an even richer and fuller tone.   All in all I would say the latest version is 10-15% better than it was a few months ago.

cheers,
Don

RLB61

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #541 on: 11 Feb 2019, 03:21 am »
First post here on the Circle, and I'm glad it's on this thread. Yesterday, I ordered a fully tricked out Model 2 preamp from Don with certain output upgrades to drive properly my low impedance SS power amp and subwoofer. Don has been very informative and patient with my incessant, voluminous questions. I look forward to getting the Model 2 in the next few weeks. Review to follow.

mresseguie

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #542 on: 11 Feb 2019, 06:26 am »
RLB61,

Oh, boy. You are in for a treat. Don’s Model 2 is a beauty - musically and aesthetically.

I’ll probably try the upgrade to the rectifier. The Polish caps will have to wait until late Fall because I don’t want to be without my baby until then.

Michael

P.S. Don’s Kootenay 120 is a perfect match for the Model 2.   :thumb:

RLB61

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #543 on: 12 Feb 2019, 04:58 am »
Trust me, I'm considering seriously the Kootenay ... Don insists that it will take the music to another level over my SS amp. One thing at a time, though. In the meantime, I'm excited about the Model 2.

backsigns

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #544 on: 6 Mar 2019, 10:45 am »

mresseguie,
I have an AVA 400r and was wondering if the .47uf cap in the pre was enough for the amp?
Thanks, Cindy

richidoo

Re: Don Sachs SP14 Tube Preamp Review
« Reply #545 on: 6 Mar 2019, 01:21 pm »
Fet Valve 400R has tube input stage so it may be OK with the small coupling cap as tube inputs usually have high input impedance. But you have to ask AVA for the actual spec to know for sure.

Sachs recommends that the preamp's load (amplifier input impedance) should be >80kOhms to prevent rolling off the bass frequencies using the 0.47uF cap.

mresseguie

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #546 on: 6 Mar 2019, 02:24 pm »
mresseguie,
I have an AVA 400r and was wondering if the .47uf cap in the pre was enough for the amp?
Thanks, Cindy

Hello, Cindy.

I'll defer to Richidoo's greater experience, and/or recommend you speak with Frank van Alstine to be certain. That said, my Model 2 sounded just fine with my old 400R. Actually, I've paired my Model 2 with nearly a dozen amps now (mine and other audiophiles' amps) and I have yet to hear a bad match.

Michael


avahifi

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #547 on: 6 Mar 2019, 03:00 pm »
All our Fet Valve series tube/hybrid power amplifiers use a 12AT7/ECC81 tube input stage and have a 1 meg ohm input impedance.  They are a very easy load for any vacuum tube preamplifier to drive.

Frank

backsigns

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #548 on: 6 Mar 2019, 03:04 pm »
 "The amps also have a  very high input impedance so they are easy loads for a preamp to drive.
The input impedance is 1 meg ohm, its a triode tube input" according to Frank in the Why not a 200r topic. I was hoping I didn't have to go any larger than 1uf on the coupling caps. 1Muf is 1000Kuf. If there was plenty of low end with .47uf that would be great, and cheaper. Thanks for your time.

RLB61

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #549 on: 14 Mar 2019, 08:37 pm »
Don told me that larger caps were needed for amps with lower input impedances. So, for example, he put 2.2uF caps onto one output to drive my 31K Ohm power amp, and 3.0 caps onto the other output to drive my 10K Ohm subwoofer.

Wig

Re: Don Sachs SP14 Tube Preamp Review
« Reply #550 on: 15 Mar 2019, 02:03 am »
Guys,

I received my modified DS2 last week with Don’s latest Polish made Deulund copy oil caps and 6BY5 rectifier and it sounds amazing! I am hearing more transparency, better sound staging and imaging, more depth, lower floor noise, more air/ambiance. Bass is tighter, midrange is purer/more organic but you are going to be knocked over by its ”HOLOGRAPHIC” presentation; sound emanating beyond the boundaries of my loudspeakers…

It is astonishing how you are immersed into the music with Don’s DS2 Tube Pre; his original DS2 is Amazing but the updated version is “UNBELIEVABLE”! For those of you who are in the market for a new pre-amp, I highly recommend that you put this pre on your short list. If you already own one of Don’s creations, get this updated version done ASAP!

I am not aware of any mods that can radically change the sound of a system for a very small investment. Act now and get your units in or orders placed soon…

Wig :)