2. amps-preamps
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Preamp Input for Coincident system - Don Sachs, deHavilland, LTA, Joule Electra?

Hi all, I'm looking to spend around 2k on a pre-amp (either new or used) to pair with my Coincident PREs (currently using their Frankenstein mono-blocks as amps; input impedance of 100kOhms). 

I'm looking for something very natural sounding, with good body, some warmth, and -importantly- it must have a remote.  The PREs are very sensitive up on top, so I need clean highs. 

I've been reading a lot of threads and have a few contenders.  Am hoping to solicit some input from anyone who might have compared the following (with PROs / CONs listed):

1.  Don Sachs SP14 - good reviews, available in budget new / long wait to get a unit
2.  LTA MZ2 - some awesome reviews, available with 10-day trial period / some "meh" revies, perhaps a bit of a "clean" sound?
3.  deHavilland  UltraVerve 3 - good reviews mentioning the "relaxing" nature - a good key word for me / new it is out of budget at 3k
4. Joule Electra LA-150 MKII - in budget used, reviews mention strengths in "tone" & "texture" - highly desirable for me / a fairly old product  

Other things to note... 

I'm currently running a PS Audio PW DAC directly to my amps and listen to all types of music; perhaps currently tilted towards "modern" music with electronica and indie influences.  I stream Tidal via ethernet via PS Audio's Bridge II card in the dac.  

While I'm sure others will criticize the DAC, I really like the PWD and it has compared favorably to both a DirectStream (the music became less natural and more analytical) and Lyngdorf TDAI 3400 (the music was very smooth, but slightly less natural with a less well delineated soundstage). 

Unfortunately, the PWD has a bad volume control (throwing away bits at under 50% volume) and the new PREs really show that distortion off.  As such, I don't like listening at low volumes... hence the desire to add a pre-amp. 

Also, obviously I'd love to get Coincident's 101D pre-amp, but I need the remote, so it doesn't work for me.  I tracked the remote version for a long time and was hoping to save up money to purchase, but apparently it was plagued by technical difficulties and often needed service (presumably that's the reason Isreal discontinued it). 

Appreciate any input.

- Chris
128x128cal3713
cal3713's avatar
cal3713 OP
1,421 posts
 
Wow. Every once in a while you ask yourself the same question and end up running into an old thread.

As an update, I’m currently running a heavily modified don sachs ds2 6sn7 preamp. Over the past year and a half of ownership I’ve replaced the stock capacitors with Duelund tinned copper CASTs on my main output, mundorf supremes on the secondary subwoofer output, replaced the input and output RCAs with pure silver wbt connectors, replaced all signal wire with 99.999% pure solid core silver, and placed a copper shield over the power supply.

I love the presentation and find it much better than both dac direct and the truth. Due to the pandemic I’ve got extra time to listen and have been putting a good 3 hours a night into the system and really enjoying every album.

I’m also about to compare it to an eml-20AM dht pre-amp that I recently commissioned. I’ve long been attracted to the dht approach due in part to various 6moons write-ups and because Coincident uses this topology in their line stage. The EML tubes my pre is based on are advertised as the most linear, lowest distortion dhts available. Very curious to see how they compare to Don’s 6sn7 design. Parts cost before labor & commission is already higher than the DS2, so it’ll be an interesting comparison.
cal3713's avatar
cal3713 OP
1,421 posts
 
I'll also note that I have since replaced my Coincident frankenstein 300bs with highly modified (diy) first watt f4s (pure solid core silver wire on either side of the circuit boards, 1600Vs of outboard power supply with over 350,000uF of capacitors, naked z-foil resistors throughout the signal path, and precision matched transistors). The 300bs just weren't powerful enough for the Coincident PREs. I ended up with the f4s over a lyngdorf tdai-3400, pass labs xa-25, and atma-sphere m60s.
mresseguie's avatar
mresseguie
46 posts
 
Chris,

Hello. I only just now discovered this thread. 

Allow me to offer you a belated congratulations on acquiring one of Don's Model 2 preamps. I'm not at all surprised you've enjoyed its sound. I'd like to ask you for a little more information concerning the mods you made.

 "As an update, I’m currently running a heavily modified don sachs ds2 6sn7 preamp. Over the past year and a half of ownership I’ve replaced the stock capacitors with Duelund tinned copper CASTs on my main output, mundorf supremes on the secondary subwoofer output, replaced the input and output RCAs with pure silver wbt connectors, replaced all signal wire with 99.999% pure solid core silver, and placed a copper shield over the power supply."

Did you perform the mods all at the same time, or piecemeal so that you could hear differences each time?
If you made the changes one at a time, which mod made the biggest positive change for you?
Did any of the mods make little or no difference?
Which would you recommend as a first mod?

So here's a little background on my Model 2 preamps. Earlier this year, I bought Don's newest rendition because I was intensely curious about how it sounds compared to the one I bought in 2015. [I just had to buy it. I'm sure you understand.] The new one has the Polish caps in the first out to best pair to my Kootenay 120. [I have no plans to mod this unit.] I may be persuaded to make some mods to my older Model 2 preamp. It's got the left and right gain dials and the original 6AX5 rectifier tube. The main out caps are Jupiter Cu, and ??? caps for subwoofer out. [Yeah, I lost track of what they are, but I'll eventually open up the bottom panel to refresh my memory.] Anyway, I can ask a friend to help me with the rectifier change. I've wondered about mods like the ones above, but never actually got serious about it because I absolutely love its sound. I'm interested in the changes you experienced as a result of the changes you made.

I look forward to your reply.

Regards,

Michael

charles1dad's avatar
charles1dad
10,250 posts
 
Hi Chris,
Thanks for the updated post today as I find your comments very interesting (As usual). The Truth line stage has received universal praise over the years and an outstanding review from Arthur Salvatore (For whom I have much respect for). A friend of mine had the Truth for well over a year in his system. He enjoyed it quite a bit but has replaced it with a Backert tube line stage which he finds better sounding.

You have very similar results with your move to the Don Sachs tube line stage which of course is active. Both of these experiences are interesting. In theory the the simpler Truth unit or a direct DAC to amplifier should be superior by removing the more ’complex’ active component from the signal chain.

There’s no substitute for actually listening and comparing. Real life encounters don’t always correlate with theoretical expectations or predictions. No doubt there are circumstances where some listeners prefer a direct source approach or using a passive component. Numerous variables are involved.  I can understand and appreciate the modifications you’ve done that further improved the sound quality. I’ve had very good results using Duelund capacitors for example.

Chris I’m quite interested in the future comparison between your current upgraded/modified Don Sachs (6SN7 based) and the DHT line stage. Should be very informative (And a lot of fun).
Charles
cal3713's avatar
cal3713 OP
1,421 posts
 
@charles1dad Indeed, I first heard about the duelunds from you and as always found that I heard the same thing when I put them in my system. I've currently got them on my pre tweeters and as output caps in both my dac and pre. I've tried a number of different caps and never heard better. I'll certainly update with some details of the Radu Tarta (Shiny Eyes, simplepleasuretubeamps) build. Thanks for all your posts, you're one of the few people with whom I find perfect opinion overlap when I try the same equipment. So valuable to have that information.

@mresseguie I made the updates in a number of steps. The only one I can't totally disentangle is the impact of the silver wbt rcas (installed concurrently with the solid core silver signal wire).  The primary upgrade I'd suggest is the output cap upgrade. I know a lot of people like the miflexs, but I found the duelunds to sound better in every way. I also preferred mundorfs to the miflexs, which just sounded flat and two dimensional in my system. Both duelunds and mundorfs produced much better 3d imaging.  You can read a bit more about all my cap comparisons on my system page (I wrote a lot due to boredom). 

It's more involved, but next I would consider replacing the stranded duelund signal wire with a solid core alternative (I use vh audio solid silver in cotton). People correctly talk about the wonderful tone of the duelund wire, but I have found that stranded wire blurs the imaging. My three DS inputs have the vh audio silver, stock duelund, and a single strand of the stock duelund run through a Teflon tube (you don't need 16ga speaker wire for small voltage preamp signals and tiny wires work just fine, see phono hookup wire, for example) so it's easy to do comparisons. I believe anyone listening to my system would be able to immediately distinguish between the three and would prefer the silver wire, then the duelund single strand, then the 16ga duelund. Again concurring with Charles, the solid core silver sounds more real than copper to me. I replaced all my amp, dac, and internal speaker wire with solid silver too and have never regretted such modifications.


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