[msommers]

I'm looking at adding a tube pre and I think there's a lot of value in both these amps. Problem is there isn't a whole lot online about either one versus say Audio Research or Conrad Johnson.

When I inquired to both Steve and Don, oddly the output caps value from each is wildly different for my power amp (Pass Labs XA30.5): 2.2 vs. 0.1 uF! Perhaps this is due to a difference in design? Don gave me a better explanation why the large cap is required which I appreciated.

I'm leaning towards Don's amp for a few reasons but the beautiful case and balanced design of the Decware is holding me back a bit. Sadly a cherry case painted in black is not a option (a one-off pain in the butt it sounded like) otherwise I think I would have put a deposit down already.

Does anyone have experience or comments with either of these particular amps?

[Whitestix]

Don Sachs modified all my HK vintage gear a decade ago and a few years ago sent me one of the first prototypes of his 6SN7 preamp.  In the progression of his preamp design, I have had 3 upgrades --- all of which are stock on his current preamp, and the end result is that this is a simply stunning preamp, the best I have had in my system in 45 years, including many preamps far more expensive.  I can't opine on the Decware Zen preamp, but Don's preamp, to me, is the Holy Grail of tube preamps at anywhere near its price point and well beyond.  I talk to Don a couple of times a week and he works relentlessly to improve the performance of his preamp, as well as the his outstanding KT88-based amp.  The latest appellation his preamp is just outstanding in its sonic performance.   I hope guides your decision.  Mark

[Wind Chaser]

I'm looking at adding a tube pre and I think there's a lot of value in both these amps. Problem is there isn't a whole lot online about either one versus say Audio Research or Conrad Johnson.

Funny, I considering these same two preamps a few weeks ago, but like you I wasn't able to find enough information on either of them, particularly with respect to how they stand up against the more well known and regarded options.

[mresseguie]

Funny, I considering these same two preamps a few weeks ago, but like you I wasn't able to find enough information on either of them, particularly with respect to how they stand up against the more well known and regarded options.

Howdy, stranger.

I checked Google Maps. Don's house is almost exactly 4 hours away from your house. Road trip! Road trip!  You already know that's a beautiful drive. Don would probably let you sit in his living room (like I did a year ago) and play anything on his laptop. Oh, he sold his old speakers and replaced them with....gotta look it up....cant' track the email down  ...... Anyway, I can't say enough good things about his preamp. He's building me his amp right now. I'll have both amp and preamp in Taiwan - and you betcha I'm going to show them off to audiophiles over there. 

Michael

[sabciu]

I got one of his Pre's on order as well!! Looking forward to it. I've read comments and reviews from very happy customers. It is a build to order, and he's not a High Volume business. I keep hearing how his gear blows the Big Boys away from a Pricepoint Vs. Performance perspective.

I'll share my experience hopefully some time in mid August! 

[Wind Chaser]

Howdy, stranger.

I checked Google Maps. Don's house is almost exactly 4 hours away from your house. Road trip! Road trip!

Hey Michael,

He's a Canuck? What part of BC? I didn't know he made an amp as well. Website?

John

[mresseguie]

John,

You didn't know? He lives in Nelson. Melody and I stayed in Nelson for a couple weeks last year. Before I listened to his system, I had planned to order his preamp and take delivery 2 months later. However, after listening for an hour and chatting with him, I decided the only sane thing to do was to immediately order a preamp there and then. Right after Nelson, we drove to Kelowna to visit Jay (Captainhemo) and sight see that area for almost a week. Then, we cruised south to visit you two. I cannot forget the delicious Apfel Strudel!!! 

You can ask Jay what he thought of the preamp. I loaned it to him while we were touring the area.

Preamp + amp + phono preamp = heaven??

If I ever try a TT, you can bet I'll buy his phono preamp.

http://www.dsachsconsulting.com/custom%20kt88%20tube%20amp.html

Michael

P.S. It's happened. I've become a fanboy. 

[msommers]

Perhaps I should drive out and visit Don when I have time in September. Seems worthwhile when considering dropping ~$4,000 almost on a blind purchase.

Though my Pass Labs was blind and it is everything I had hoped (albeit lots of online coverage...). I even want to eventually move up to a XA100.5 when finances present themself

[Steve]

I'm looking at adding a tube pre and I think there's a lot of value in both these amps. Problem is there isn't a whole lot online about either one versus say Audio Research or Conrad Johnson.

When I inquired to both Steve and Don, oddly the output caps value from each is wildly different for my power amp (Pass Labs XA30.5): 2.2 vs. 0.1 uF! Perhaps this is due to a difference in design? Don gave me a better explanation why the large cap is required which I appreciated.

Does anyone have experience or comments with either of these particular amps?

Are you talking output capacitor of the two preamplifiers? If so, I can tell you that if one is using a 0,1uf output capacitor, even with negative feedback, the value is way out of line for a preamplifier.

The reactance of a 0,1 uf at 20 hz is ~ 80k ohms. With an amplifier input impedance (Z) of 100k ohms, one is losing ~ 45% of the bass a 20 hz, approximately -6db down. At 50hz, one is losing ~ 24% of that signal, about -2.5db.

With an amp input Z of 50k ohms, one is losing well over 60% at 20hz and ~39% at 50hz.

If I remember correctly, the input impedance (Z) of your Pass amp is around 20k to 30k. Correctly if I am wrong.

Cheers
steve

[lancelock]

I have some friends that love Don Sachs preamps but I have not heard them so I can't personally comment. I did own the Decware Zen for a while and it sounds fine. When I realized I didn't need balanced cables I replaced it with a Linear Tube Audio MZ2-S and it is in another league than the Decware. No going back, the LTA gear is killer.

[msommers]

Are you talking output capacitor of the two preamplifiers? If so, I can tell you that if one is using a 0,1uf output capacitor, even with negative feedback, the value is way out of line for a preamplifier.

The reactance of a 0,1 uf at 20 hz is ~ 80k ohms. With an amplifier input impedance (Z) of 100k ohms, one is losing ~ 45% of the bass a 20 hz, approximately -6db down. At 50hz, one is losing ~ 24% of that signal, about -2.5db.

With an amp input Z of 50k ohms, one is losing well over 60% at 20hz and ~39% at 50hz.

If I remember correctly, the input impedance (Z) of your Pass amp is around 20k to 30k. Correctly if I am wrong.

Cheers
steve

Hi Steve,

Yes the input impedance is 30K/20K (SE/BAL) as you mentioned and was told "No problem with the input impedance of your XA30.5, in fact that's ideal. The output caps are 600V .1uf if we go with the Jupiter beeswax upgrade" from Decware vs. "You will need a 2 uF output cap to drive the low impedance SS load" from Don where I asked for Jupiters as well.

I really don't know or understand how to calculate what I need so I trust the builders. All I know is that ideally I'd like for the output impedance to be ~10-20x less than the input impedance of the Pass Labs. I really love this power amp and if anything I will go with the XA100.5 in the future which fortunately has the exact same input impedance specs!

I have some friends that love Don Sachs preamps but I have not heard them so I can't personally comment. I did own the Decware Zen for a while and it sounds fine. When I realized I didn't need balanced cables I replaced it with a Linear Tube Audio MZ2-S and it is in another league than the Decware. No going back, the LTA gear is killer.

Did you have the latest Decware Zen model or the older one? In what way(s) did the MZ2-S supersede it? Thanks!

[driguy]

You can use this calculator to show the differing cutoff frequencies versus capacitance and input impedance.
https://www.v-cap.com/coupling-capacitor-calculator.php

[msommers]

Using that calculator it does seem that a 2.2 or 3.3uF outcap is best. Thanks so much!

[Steve]

Hi Steve,

Yes the input impedance is 30K/20K (SE/BAL) as you mentioned and was told "No problem with the input impedance of your XA30.5, in fact that's ideal. The output caps are 600V .1uf if we go with the Jupiter beeswax upgrade" from Decware vs. "You will need a 2 uF output cap to drive the low impedance SS load" from Don where I asked for Jupiters as well.

I really don't know or understand how to calculate what I need so I trust the builders. All I know is that ideally I'd like for the output impedance to be ~10-20x less than the input impedance of the Pass Labs. I really love this power amp and if anything I will go with the XA100.5 in the future which fortunately has the exact same input impedance specs!

Did you have the latest Decware Zen model or the older one? In what way(s) did the MZ2-S supersede it? Thanks!

I think 20 times less than 30k ohms input Z at 20hz is preferred, but the design might alter that to 10 times (in case of too much bass at 20 times), or 30 times (in case of lacking bass at 20 times).

Also, the +/- Xdb specs for each component add up. An overly simple example is if two components are each - 0,1db, the both together would be -0,2db.

Cheers

Steve

[jsm71]

Like lancelock, who recommended the Linear Tube audio MZ2-S preamp over the Decware, I fully agree.  I am using the MZ2-S today and it is indeed special, exploiting David Berning's design magic.  I didn't use the Zen preamp but have heard it many times at a friends house, and I had a couple of Decware amps before fully switching to LTA gear (amp and preamp).  My prior preamp was a Cary SLP-98P.

I do have Don Sachs' phono stage and that has really taken my LP listening to new levels.  Don's work is superb so if you are considering his preamp you can't go wrong.  If you are considering an alternative to Don, LTA would also be my recommendation.

[msommers]

Thank you JSM, that was really helpful! 

How would you say the Cary compared to the Decware and now LTA preamp?

[mresseguie]

msommers,

You have a pm.

Michael

[jsm71]

My Cary was the most feature rich of the three, especially since it was configured with a phono stage.  I loved the flexability.  Both the Decware and MZ2 are bare bones functionally, neither having a phono stage.

I'd say sound wise the Cary and the Decware sounded pretty similar.  The Cary's use of 6SN7 tubes gives it an edge in linearity.

I had an emotional attachment to the Cary.  I thought all was great, I loved everything about it,  and I didn't want to have to go shopping for the phono preamp.  A local friend who had the MZ2 brought it over shortly after I had already bought the LTA ZOTL40 amp.  OMG, game over.  I can't attest to running the MZ2 against other amps, but the match to the LTA amp is a no-brainer.  I put in my order the next day.

Unless you need tons of input switching, the MZ2 is an amazing preamp.  It was originally designed as a superb headphone amp, which it does quite well and it puts out a full watt of power if you have high efficiency speakers.  I know of a couple of people using just the MZ2 as an integrated amp with their HE speakers.  Pretty cool.  My speakers need the ZOTL 40 to sing well.