Don Sach's pre amp

Hi all,
I have modified the preamp to take a 6BY5 rectifier because it sounds better and you can source 6BY5 tubes for $12 or less. If you own one of my preamps and pay the return shipping I will modify it for you and provide a 6BY5 tube for $75.   If you own an SP14 kit or any other version of this preamp, please DO NOT JUST PLUG A 6BY5 TUBE INTO YOUR PREAMP AS YOU WILL DAMAGE IT AND IT WILL NOT WORK!   This modification is something I developed for my customers only. I will NOT share the details and I will NOT modify any preamp that I did not build. Sorry, but this is what sets my gear apart from the kit versions.  I have gotten notes from a few people who have built the kit version and asked for the recipe.  No, sorry, but I do not share any of my mods.

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; sounds 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 :)

If anyone is still around...

Giving a lot of thought to Don’s preamp. But do have some questions before I call him:

- Tonally: "neutral" or some degree of warmth (short of classical tube sound)? I don’t like what most people call neutral, which I find cool and uninvolving once the marvel at PRAT passes.

- I have a Lampi Atlantic TRP dac, which with some tube rolling I find much better than the very good DirectStream -- except that I have active ATC speakers that are balanced (10K impedance) and one set of my Lampi’s outputs are faux-XLR, i.e., unbalanced. I’ve had some mismatch problem running from those directly to the ATC’s in terms of hum/buzz. We’re working on that now. But if I add the Sachs preamp in between with its unbalanced outputs, should I expect to face the same problem?

- Is a remote standard?

- What does the preamp weigh? How tall is it with tubes?

thanks,

Can't answer all of your questions, but I'd say the DS pre is a touch on the warm side of neutral. A little tough to say because so much will depend on what tubes and output capacitors you have on it.

With the cv-181s and miflex copper caps, I found it pretty "modern" sounding. Extended and detailed. I liked it and definitely found that it improved the sound of whatever dac I fed it (ps audio perfect wave dac -> directstream dac -> audio mirror tubadour III se). 

I did eventually settle on vintage tubes (40s/50s rca grey glass vt231s and Sylvania Jan's) however. I lose a little extension with them, but gain refinement, tonality, and imaging. 

I also tried out a variety of output capacitors. The miflex had good tone, but were very 2 dimensional in my system. Mundorf Supremes added depth to the imaging, mundorf Supremes silver/gold in oil added even more depth and refinement but took away some bass, and v-cap tftf were too cold (tonally) for my system. I have some duelund tinned copper cast on the way.

All of these variables definitely change the sound, which I like to attribute to a quality, revealing circuit.  Does make it a little hard to nail down the pre's sound for a new buyer though.  

The pre does come with a remote by default. The newest modification gives you both volume and input switching but loses balance control. If you need balance control (not available on the remote) then you only get remote volume and muting. 

Final caveat, as always, these impressions are likely very system dependent. I need to update my dac description, but you can see the details on my system page.

Also, do note that input impedance to Don (or any other manufacturer). If the preamp design uses output capacitors you'll need 8uf caps to prevent any low frequency rolloff (https://www.v-cap.com/coupling-capacitor-calculator.php).  That'll limit your boutique cap choices unless you've got no budgetary constraints. If you were to buy the miflex copper caps yourself, it'd be $500 at partsconnexion... And they're huge, maybe too big to fit. 

I'm sure Don will have some options for you however. The mundorfs are smaller and cheaper.