Don Sachs SP14 Tube Preamp Review

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MasterHiFi

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #460 on: 13 May 2018, 05:15 pm »
Hi All,

New Circle member here. I was specifically led here due to this thread. I have finally finished the entire thread and learned quite a bit, so thank you all for sharing your experiences.

It took me a little while just to figure out the difference between the Tubes4HiFi version and the Don Sachs offering,. Yes, I'm slow, but I'm fully dialed in now.

The reason I was searching is because I have a line on - send the children from the room - an SP-14, though it is NOT the Don Sachs build, unfortunately, but one of the venerable kit builds from Roy Mottram with the Mundorf oil caps. Unbelievably, it alsohas in the same chassis the ClassixAudio PP2 phono stage, with three line level inputs plus a tape / processor loop, making it a very versatile unit. I am finalizing the details with the seller, but can't help but be excited already.

My question is, is there anything preventing me from sending this to Don at some point (this purchase will wipe me out for a while) to get his upgrades? Also, if you had to choose, what would you do first, get the upgrades or dress it out with the CV181-Z Black Treasures - i.e. what would provide the most immediate improvement in sound? (Yes, I have to choose.)

This will be my first venture into tubes, though I've been wanting to make the leap for longer than I care to mention. I will also be converting a pair of high powered PA  tube amps into home audio amps. In the neighborhood of 90 - 100 wpc monoblocks running 6550s. Unfortunately, my speakers are very inefficient Snell CVs that are spec'd at 91db but as measured in a Stereophile review are in reality actually a meager 87 db, so unfortunately I do require an unusual amount of power. I also run a custom built sub with two stereo 12" drivers in a sealed cab that I will power separately with a SS amp, and fortunately the SP-14 has two sets of outs, balanced and unbalanced.

I also have the opportunity to pick up a PS Audio Power Plant Premiere that comes with a free little Topping TP-23 USB DAC and I wonder if you guys think it's worth it or is this a lot of hype? On top of LP and CD, I do listen to quite a bit of streaming radio (RadioParadise.com - best station EVER) as well as FLAC and MP3 but I don't have the $$ for expensive DAC solutions, at least not yet, though I know the owner / engineer of Empirical Designs and it's possible that he might set me up with something.

Anyway... Wondering your thoughts and recommendations? All help and opinions greatly appreciated.

Dan

Tyson

Re: Don Sachs SP14 Tube Preamp Review
« Reply #461 on: 13 May 2018, 09:03 pm »
Tubes first.  They have a much larger impact on the sound vs internal upgrades.  At least IME.

genjamon

Re: Don Sachs SP14 Tube Preamp Review
« Reply #462 on: 13 May 2018, 09:58 pm »
Have you already been in touch with Don to determine what’s feasible within that chassis? I’d want to first know whether you can fully implement Don’s solutions or not. That said, I haven’t ever compared the two versions with the same tube set, so can’t really say what makes the biggest difference from experience.

MasterHiFi

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #463 on: 13 May 2018, 11:13 pm »
Tyson, thank you, that was my assumption as well, but of course it's better to hear it from someone with experience. That will be the order of operations, then. It's curious that I haven't seen anyone who has compared the original Roy Mottram build with the DS version. I would assume that would be a very natural comparison, though the perils of assumption are built into the word. I think the biggest benefits to Don's upgrades would be the better caps, though the Mundorf's are no slouches, as well as the better wiring. Unless I'm missing something.

Have you already been in touch with Don to determine what’s feasible within that chassis? I’d want to first know whether you can fully implement Don’s solutions or not. That said, I haven’t ever compared the two versions with the same tube set, so can’t really say what makes the biggest difference from experience.

genjamon, I've thought about that exact issue. I do have a photo of the interior that I can send to Don and see if there are any space problems, particularly relating to the very large caps that would likely be the biggest obstacle. The existing wiring is very neat and professional, so I believe he would find it unobtrusive to work on. Lemme see if I can successfully upload a pic and let me know what you guys think...














Now as I'm looking at it, if those white boxes are the Mundorf caps then it looks like the BIG upgraded cans that Don uses don't have a chance fitting in there. It's a neat, but very tight build, but I know nothing about tube circuits so maybe I'm looking at it wrong. Help me out here and tell me what I'm looking at.

Thanks again for your help.

Dan





screener

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #464 on: 13 May 2018, 11:47 pm »
Have you already been in touch with Don to determine what’s feasible within that chassis? I’d want to first know whether you can fully implement Don’s solutions or not. That said, I haven’t ever compared the two versions with the same tube set, so can’t really say what makes the biggest difference from experience.

I totally agree that a call to Don would be my first line of business.

mresseguie

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #465 on: 14 May 2018, 01:34 am »
Hi, Dan.

Welcome to AC, and congrats on getting an SP14.

I only have experience with the Don Sachs amp and preamp (own both) and it's been a while since I chatted with Don about design/implementation differences, so my memory may be off a bit. Anyway, Don uses better and larger transformers that I imagine will not work in this case. I also highly recommend contacting Don to discover what he can do, and to know what his timeline is. He's a lot busier now than he was two years ago.

Do you know the brand or model of the volume control? It looks to be different from the one Don uses.

Regards,

Michael

 

MasterHiFi

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #466 on: 14 May 2018, 03:03 am »
As you can see from the photos, the Preamp is very deep from front to back, with the power supply physically separated and shielded from the rest of the chassis with a mu-metal barrier, but the Preamp is NOT very deep from top to bottom, obviously to keep the tubes on top and give them air to breathe.

The small three socket board at the very back is the phono stage. It's FR4 glass reinforced woven fiberglass with copper-clad foil on both sides and utilizes an updated Marantz 7C circle with a startlingly accurate RIAA curve, with excellent left-right channel matching. When built using DC to supply the heaters it is supposed to be dead quiet.

Can anyone tell by looking what volume pot is used? That's one thing Don can surely upgrade, as his single resistor stepped attenuators must be phenomenal for their lack of influence on the sound, not to mention helping maintain channel separation.

Just thinking out loud...

Dan




genjamon

Re: Don Sachs SP14 Tube Preamp Review
« Reply #467 on: 14 May 2018, 03:11 am »
Yeah, Don’s implementation requires a fair bit of extra space, and that chassis of yours already looks pretty cramped. The regular Tubes4Hifi kit chassis is much larger I think, and might be able to work, if you can get Don to develop a new layout for such a chassis.  But I’m skeptical about the one in the pics you provided.

I actually have heard both the Tibes4Hifi SP14 and the DS-2. It was on the basis of hearing the Tubes4Hifi version with some NOS RCA tubes that I chose to pursue the DS-2. The Tubes4Hifi pre won out over several active and passive preamp designs in terms of overall musicality, in my opinion. It was a couple months after I returned it to its owner that I had the DS-2 in hand, though, so I don’t have a clear comparison between the two. However, I do feel like the DS-2 and Tubes4Hifi share the same overall character, but with the DS-2 just being a cleaner and more refined presentation. Sorry I can’t comment on the degree of difference with any certainty. But I would venture a guess that while the difference is likely substantial, it won’t diminish the overall listening pleasure. I’ve heard my friend’s Tubes4Hifi several times now in his system, in mine, and in a guest role at another friend’s house/system.  In each case, the system had a very musical, engaging, and pleasing sound. It brings a heart and soul to whichever system it’s in.

MasterHiFi

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #468 on: 14 May 2018, 03:32 am »
Hi, Dan.

Welcome to AC, and congrats on getting an SP14.

I only have experience with the Don Sachs amp and preamp (own both) and it's been a while since I chatted with Don about design/implementation differences, so my memory may be off a bit. Anyway, Don uses better and larger transformers that I imagine will not work in this case. I also highly recommend contacting Don to discover what he can do, and to know what his timeline is. He's a lot busier now than he was two years ago.

Do you know the brand or model of the volume control? It looks to be different from the one Don uses.

Regards,

Michael


Hi Michael,

Pleased to meet you. I read all of your posts, most informative, thank you! So I know how much you're digging that KT88, not to mention your DS Pre. Funny, I was typing my question about the volume pot when your comment came in. I'm going over to Tubes4HiFi to see what comes with the kit, one sec, I'll be right back...

See, you didn't even notice I was gone. In the parts list it just says "21 step volume attenuator - $72.00" - no brand is mentioned. The one shown above is a remote version, but that's all I know. Will find out more tomorrow

Thanks for your help, I'll get as much info as I can, but it looks pretty crowded in there and not much room for upgrades. :(

Dan

A_shah

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #469 on: 14 May 2018, 06:03 am »
That is a very nice Build you have on the pre amp  :popcorn: I have the experience with the Tube4hifi-Sp14 pre-amp that was loaned to be by WhiteEx, for about 3 weeks, that unit had clarity caps and sounded no where near what the DS 2 I got  from Don , I think Don just uses a better quality IC board that he has specially made by Tube4hifi,(Roy M) and than has his own wiring and Schematics  call Don but I don't see how he could change the Schematics on your unit plus Don voices the the pre-amp , so if you like the sound of your pre-amp just stay with it or sell it and get a fresh one from Don.
I would go with  the tubes firsts , if I am not mistaken your caps would be on the IC board ( the two round one in the black)
 
« Last Edit: 14 May 2018, 08:24 am by A_shah »

BRN

Re: Don Sachs SP14 Tube Preamp Review
« Reply #470 on: 14 May 2018, 02:16 pm »
Dan,

The VTA SP14 is the board that is used on in the DS-2. Where Don's version differs is some of the parts used in the DS-2. Don is using film caps in the power supply, which there are four of these. I do not think that they will fit into that chassis. How much of a difference this makes to the sound is up for debate, but I'm in the camp that there is a slight improvement, based on other projects I have done. Also, the DS-2 uses the Khozmo attenuator. It looks like the volume control in your pictures is either an Alphs or TDK motorized volume control. Roy sells his kit with the eBay DACT step attenuators. They are very good and hard to beat for the price, and blow away the Alphs pots. The output caps in this pre ate good. There is space on the board to add another set of caps, but not sure where you would put the RCAs.

The kit you have is very nice and the biggest improvements you could make would be with the tubes, output caps, and volume control. The wire and power supply film caps not so much. It also includes a phono section and nice chassis.

I hope that helps.

Brad

MasterHiFi

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #471 on: 14 May 2018, 06:02 pm »
Yeah, Don’s implementation requires a fair bit of extra space, and that chassis of yours already looks pretty cramped. The regular Tubes4Hifi kit chassis is much larger I think, and might be able to work, if you can get Don to develop a new layout for such a chassis.  But I’m skeptical about the one in the pics you provided.

I actually have heard both the Tibes4Hifi SP14 and the DS-2. It was on the basis of hearing the Tubes4Hifi version with some NOS RCA tubes that I chose to pursue the DS-2. The Tubes4Hifi pre won out over several active and passive preamp designs in terms of overall musicality, in my opinion. It was a couple months after I returned it to its owner that I had the DS-2 in hand, though, so I don’t have a clear comparison between the two. However, I do feel like the DS-2 and Tubes4Hifi share the same overall character, but with the DS-2 just being a cleaner and more refined presentation. Sorry I can’t comment on the degree of difference with any certainty. But I would venture a guess that while the difference is likely substantial, it won’t diminish the overall listening pleasure. I’ve heard my friend’s Tubes4Hifi several times now in his system, in mine, and in a guest role at another friend’s house/system.  In each case, the system had a very musical, engaging, and pleasing sound. It brings a heart and soul to whichever system it’s in.

genjamon,

Thank you, this is very helpful. It would make sense that the overall character would be similar, if not very, very close, with some improvement in transparency, focus, as well as bass depth and articulation, and possibly even stronger attack, as Don's upgrades address these aspects of the sound. But overall I would expect them to be at least close. And I think upgrading the tubes will get me at least part of the way there.

I think the volume control upgrade is doable, but really I will have to keep my eyes peeled for an accommodating chassis to go much beyond that. Not the end of the world, maybe just not right away is all. But when I do get it I will let you guys know how it sounds.

Anyone have any experience with the PS Audio PP Premiere? I sit here and watch the lights go up and down all day long, so I know the power here is pretty lousy, as is the wiring for the whole house. Just wonder if I can expect any audible improvements with this device?

Thanks for your help, you guys rock!
Dan

BRN

Re: Don Sachs SP14 Tube Preamp Review
« Reply #472 on: 14 May 2018, 07:44 pm »
I think the volume control upgrade is doable, but really I will have to keep my eyes peeled for an accommodating chassis to go much beyond that. Not the end of the world, maybe just not right away is all. But when I do get it I will let you guys know how it sounds.

Dan,

It looks like the chassis is from Landfall Systems. I would think that Dave could help with providing options to make it larger. Maybe the height, since the overall width and depth look to be large.

Brad

MasterHiFi

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #473 on: 15 May 2018, 10:01 am »
Dan,

It looks like the chassis is from Landfall Systems. I would think that Dave could help with providing options to make it larger. Maybe the height, since the overall width and depth look to be large.

Brad


Brad, 

Thanks! You have a good eye to recognize it from those pics. At first I read it as Land-FILL Systems! Heheh... I am going to go look them up right now.

Yeah, some height would be great, it's already really deep. Will let you know what I find out.

Thanks,
Dan

aguaazul

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #474 on: 15 May 2018, 04:41 pm »
Current Khozmo Boards 'may' have a popping issue. Mine sure did and it's in for repair. FYI!  PM me for details.

Speed Racer

Re: Don Sachs SP14 Tube Preamp Review
« Reply #475 on: 21 May 2018, 06:24 pm »
Deleted.

brucemarnold

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #476 on: 22 May 2018, 06:48 pm »
I'm just curious how Don's SP14 Preamp would line up with a Rouge Audio ST100 amplifier? I'm trying to decide between that combination, Don's own amp, or a ModWright LS100 and a ST-100..  Anyone have thoughts on these combinations?

aguaazul

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #477 on: 30 May 2018, 05:37 pm »
Current Khozmo Boards 'may' have a popping issue. Mine sure did and it's in for repair. FYI!  PM me for details.

I got my DS2 back, it has this in it now. The relays are not on a separate board.
https://khozmo.com/64_steps_relay_khozmo_attenuator.html

These seem to be problematic for some users. Not all.
https://khozmo.com/relays/shunt2a.jpg

Cheers,
Aguaazul

mresseguie

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #478 on: 30 May 2018, 06:24 pm »
I got my DS2 back, it has this in it now. The relays are not on a separate board.
https://khozmo.com/64_steps_relay_khozmo_attenuator.html

These seem to be problematic for some users. Not all.
https://khozmo.com/relays/shunt2a.jpg

Cheers,
Aguaazul

Enjoy!

I assume our Khozmo VCs have the Vishay SMD resistors. I wonder how different the SQ might be with the AMtrans AMRG resistors(?). I have too little experience to know.

Michael

mresseguie

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Re: Don Sachs SP14 Tube Preamp Review
« Reply #479 on: 30 May 2018, 06:33 pm »
I'm just curious how Don's SP14 Preamp would line up with a Rouge Audio ST100 amplifier? I'm trying to decide between that combination, Don's own amp, or a ModWright LS100 and a ST-100..  Anyone have thoughts on these combinations?

Hello, Brucemarnold.

I haven't responded to your query till now because (of the amps you listed) I only know how the Model 2 (SP14) sounds with the Kootenay 120 amp. I've heard my Model 2 with AC member Aldcol's KWA 150 SE amp. Both combinations are heavenly.

I had hoped someone else who is familiar with the other amps would jump in to respond.

Where are you located? Perhaps, you can visit someone with Don's gear?

Michael