Thats a lot of cool features for that price.
I think I’m most interested in the imaging and the details on the highs. Theres a little muddiness in the midrange but that’s not bothersome. The AI is very musical and sweet and I do want to keep that quality.
Here's my rig:
Magnepan MG .7
Audible Illusions Modulus 2d
Bryston 4b-st amp
Rythmik f12 sub
Your amp requires 1.4vrms to reach maximum power. Your sources are all digital which means you are already above 1vrms into your amp.
Let me pose the the question of why do you need a preamp? Adding amplification that will be deamplified via the volume control can only add distortion. Have you considered using a DAC with a built in volume control or a passive volume control such as a transformer volume control
Your amp requires 1.4vrms to reach maximum power. Your sources are all digital which means you are already above 1vrms into your amp.
@ajcrocker1 , this thread may help bring you up to speed on the OP's situation.
He just tried a tube preamp (AI) and found that it sounded MUCH better than his passive preamp.
I previously was using the Mod Squad line drive passive preamp. The difference in sound quality astounding. The passive Mod Squad sounded two dimensional in comparison. And the magical thing was, mind you I have never heard a tube preamp before, was that the AI connected the note playing with the note that it just passed and to the note that it would it would soon become. It's amazing
I have Don Sachs' SP-14 (currently back for the latest upgrades). It is absolutely killer! Musicians in the room, goose bumps, the whole nine yards. It hits way out of its price point. I've had quite a few expensive and highly rated preamps over the years, and the SP-14 is up there with the best of them (for a lot less money).
As Charles says, the Linear Tube Audio Micro ZOTL is supposed to be amazing as well, however I have not heard it.
As someone who builds tube gear and owns many pieces from various manufacturers, a couple pieces of advice when buying tube gear.
1 Understand the tube being used. Look at the tube data sheets. Look for high transconductance, greater than 6500 ohms
2 Build quality is paramount. If AC heaters are not done right your signal to noise ratios will be poor
3 Older products may needs rebuilt. Many of the large capacitors go bad after a 20 years
4 Stick with a 9 pin tube as they provide internal shielding. Unless it has a good DC heater supply
5. Do a little research on what a SRPP, Mu Folllwer and White Cathode folllower is and what their pluses and minuses are
6 Finally the quality of parts is paramount. Poor undersized caps can lead to poor frequency response. Carbon resistors color sound
As to passive preamps a good transformer volume control costs but they are very transparent and have plenty of drive as the excess voltage is converted to current. With a tube preamp your minimum gain will be 20 which is 20 more times than your amp needs. Which means the rest of it will be burned across a carbon pot. Unless a good stepped attenuator has been used
BTW my main two amps are a parallel SET 300b and a 845. I also have a MC225, a VT100, Sophia Baby Amp, and a Unison Reaerch 845. Just to say I am not against tubes.
I disagree with the statement that tube preamps have a minimum gain of 20. My Line Stage has 10 dB of gain and some active preamps have only 6 to 8 db of gain.
9 pin tubes are the most common choice for preamps however 8 pin (octal) are excellent candidates as well. For example the 6SN7/12SN7. My preamp uses a 4 pin tube (DHT) 101D and it's superb IMO. It always boils down to implementation when all is said and done.
"I think I’m most interested in the imaging and the details on the highs. Theres a little muddiness in the midrange but that’s not bothersome."
Of all the components, your current preamp is the strongest piece with regards to the above qualities. Your amp is a bottleneck, and most likely your source is too. One mismatched component can wreck your systems imaging and details.
Of the 9 pin tubes the 12au7 is going to give you the lowest gain which when setup properly will be a gain of 17 to 20. This is where looking up the tube data sheets come in handy.
A gain of 1 will be a cathode follower or amtube buffer. Tube like the 300b, 845, and 2a3 will have a gain around 4
Mudiness in a system with decent components can easily be caused by the room. The book How To Get Better Sound is an excellent resource. Running test tones through the system (30, 50, 100, 200, 500, 1k, 2k, 5k, 10k, 15k at a minimum) will help you map the room. A poorly designed tube preamp may de-emphasize the low frequencies, due to the undersized coupling cap, thereby reducing the the amount of excess bass in the room. If you have already mapped the room and added diffusers and absorbers where necessary you can ignore this.
Sfall and Ajcrocker1 those thoughts raise a couple of questions then on how to think about this. My thinking was this. The leap between the Mod Squad and the Audible Illusions in sound quality was monumental. It changed the experience entirely. I love what I'm hearing. I want to improve upon it and try to get a little better imaging and detailed highs. I don't really think about anything as a problem to resolve so much as improve on what I have. I assume it would be just get an even better tube preamp. I thought that the preamp had such a huge influence that it would be the piece to continue to build upon. So, if I was to swap out the preamp I have or the amp that I have, I would think a 1500 preamp vs. a 1500 (I could go up to 2k on that because the Bryston I wouldn't keep) amp would get me the bigger reward in improved sound. I don't even want to know how Tidal's sound with the node compares to cd or high def digital. Tidal is too much fun and I don't want to have a knock in my head against it because it will drive me nuts! I have to see about what improvements configuration can contribute here.
Have you read the book How To Get Better Sound?
If you have standing waves in your room a tube preamp may have nullified some the affect with less bass. The way a basic tube preamp works is:
Source select to volume control
Some sort of resistor divider to cut down on the input signal if the gain is too much
An output coupling cap
The coupling cap in conjunction with the input impedance into your amplifier makes a high pass filter.
cuttof freq is 1/(6.28*resistance*capacitance)
If any of the caps are undersized you might get a -3dB point at 15 to 20 hertz. This would mean less bass
Your room has the largest impact of any component in your system. A good system is a hotel room that has not been treated will sound bad not matter how much it cost.
My suggestion is to do what you can to make sure you understand why you are having the problem and the strengths and weaknesses of the component the new component in question.
I purchased diffuser plans on line and had a carpenter make them. This help the mids to low highs. Added bass traps in the corners and that brought my room to neutral. When you talk in the listening room it sounds very different than any other room. Less echo and clearer speech.
"The leap between the Mod Squad and the Audible Illusions in sound quality was monumental. It changed the experience entirely. I love what I'm hearing."
I thought you were using the AI.
"I thought that the preamp had such a huge influence that it would be the piece to continue to build upon."
In my opinion, the preamp is the most important piece to get right, assuming you made no major mistakes with your other components. Every component contributes to imaging and spacial presentation, so when I was looking your system over, I picked the components that were most likely the weakest in this area.
" So, if I was to swap out the preamp I have or the amp that I have, I would think a 1500 preamp vs. a 1500 (I could go up to 2k on that because the Bryston I wouldn't keep) amp would get me the bigger reward in improved sound."
You're over simplifing the issue. The biggest 2 mistakes you can make are using cost as a measure of quality and going with tubes because you assume they're better. System matching is far more important than price or design. In my own system I use $2500 speakers and have a pair of $10,000 sitting in my closet collecting dust. Tubes guarantee nothing. My advice would to be listen to a component and judge it based on sound quality. If it happens to be tube, fine. But if a SS components sounds better, then that's the one you should buy.
I got one of Don's first preamps. It was fantastic, bettering my HK, CJ, Modwright, Berning, and any preamp I had had. His latest iteration of the preamp is significantly better than his prototype, and I have had all the upgrades. There is magic in 6SN7 tubes, as Don will tell you, and in my long life as an audiophile, I am simply in awe of the performance of his amp. His KT88-based amp will no doubt be every bit as fine. Don is a prince of guy to deal with, too. Mark
You might consider Tubes4HiFi's SP-13, which is a noval version of the SP-14, uses 6CG7 tubes. It didn't acquire the following that the -14 has and I believe is no longer advertised, but I have owned both and the -13's sound is every bit as good as the -14. Roy may have a few boards left for the -13 and perhaps even a full kit you could get on the cheap. If your choice comes down to either, by all means upgrade the caps and they'll blow you away.
You might want to check out Brown Audio Labs. I currently have Denny's SP-2B model which uses 9 pin tuned plus has a ballance control. It is very good. A few years ago I had an Audio Research SP8 which was beautiful ounding but had very little base reproduction. It was restored by Audio Research themself with ne tubes. My Brown Audio Labs model is truly exceptional for the money. Plus it's phono section is it's best festure by fsr. Oh yes, it cost me only $1194, which included shipping.
My first tube preamp was an Audio by Van Alstine T-8. I thought it was pretty awesome until I heard Don Sachs's SP14/Model 2 preamp.
I know guys who are satisfied with their T-8 preamps. AVA now has a new tube preamp for under $1000, but I have not heard it. Perhaps it can satisfy you; perhaps not.
I am a proud owner of the D Sachs Model 2. I upgraded just about everything possible, so my final cost was nearly double your $1500. However, this isn't necessary. You can easily begin with his base model and upgrade as you wish or are able to.
The soundstage is wide and deep. Instruments and voices are crystal clear.
I'm pretty confident that this will be my last preamp upgrade.
Enjoy your journey!
Don Sachs here. I am not trying to sell anyone anything and don't want to violate any of those sorts of rules so I will give my opinion. I have built and sold over 40 custom preamps built around the sp-14 board. My opinion is that if you take that board and use really good parts, wire, and attenuators you get a preamp that will compete with anything I have ever heard at any price. You cannot do it for $1500 though. More like $1800-$2200 depending on the case, cap and tube choices. It will run circles around a stock sp14, which is already a great bargain and wonderful preamp. That said, that extra $300-$700 is money well spent and will give you easily a 20-30% improvement. I have my own opinions on coupling caps and have heard many. The beauty of the sp14 is that there is really only one coupling cap and that is on the output. The rest is direct coupled except for the small cap on the Akido buffer and a decent cap is all you need there. The preamp should be tailored to match the rest of the system. Impedance matching is important. I have built passive preamps with very good attenuators and my opinion is they are nice, but a good tube preamp makes the music just leap out of the speakers in a way no passive preamp I have ever heard can. I have a number of customers who went from passives to an active tube preamp based on octal tubes and never went back.
Also, I have probably worked on 1000 pieces of audio gear in the past decade, both vintage restorations and lots of custom builds. I have my opinions on which resistor types sound best where, what caps to use where, etc... Everyone has their taste. What I can say is that I prefer the 6SN7 and other octal tubes in a preamp over ANY of small 12A*7 types I have ever heard.
Good luck to all and happy listening.
Since Don Sachs won't brag himself up, I will. My SP-14 has gradually morphed (as time & funds have permitted) into a DS-1, and now we're getting ready to bring it up to his current line of DS-2s. Jupiter coupling caps, Dueland wire and film caps. The DS-1 was a step-level improvement over the original SP-14, which was a very sweet sounding pre-amp to begin with. Don's a delight to work with, too. He and Jim McShane have been restoring H-K Citation amps for years, so he knows a thing or two about great sound.
As with Deepee, I have had the caps upgraded for a modest cost and the sonic improvement was exactly as Don portended. His latest improvement is to employ the very fine Dueland wire for the internal wiring. I have a a stock SP-14 in my bedroom system which is very good, but by comparison, Don's preamp profoundly better. Don is now a devotee of the Shuguang CV181 tubes and I agree 100%....they are far better than any NOS tube out there other than a few of the Holy Grail of uber expensive tubes.
Don upgraded my HK C-I, C-II, and C-V and they were outstanding. However, his preamp is a much much better than the C-I and I am quite sure his new KT88-based amp will be much better than the C-II. Google "Don Sachs Consulting" for a link to his website. There may be better preamps available, but only if you are willing to spend dramatically more money.
Hi , I have the Rogue RP-1. I spent $250 on 1 pair of Telefunken Tecktronix 12au7's after spending $130, on a pair and JAN RCA tripple mica blackplates and $100 on a Silnote cord . I haven't tried the phono stage , and the headphone stage is not tube driven and is a little lacking . So you pay $1600 for a nine pin setup and have to replace the $25 a pair JJ's. I'm cosidering Dons amp and a pair of Bob Latino 125's. But I think I'll be at about $2500 with upgrades with Bob. Happy Listening . PS, I'm MID FI AND HAPPY 😊
Another shout out for Don Sachs.
I have had the absolute enjoyment of his SP-14 Model 2 for about 6 months now.
Yes, as all have mentioned Don is a stand up guy to deal with. Even more important though is that he is a master at selecting just the right parts to make this great design really sing.
I am running the Bob Latino ST 120 amp which I love. That said Don's amp looks to be even more of the same has been on my mind.
I haven't heard any $1500 tube preamp that can compare with a "tweaked" Tubes4hifi's SP14. By "tweaked" I mean put some better parts in it - Duelund/Jupiter/V-Cap output caps, good quality resistors in the signal path, better components for the PS, good attenuator, Shuguang CV181 tubes, etc. The price would go up from $1500, but you would have a preamp that can easily compare with a lot more expensive preamps. If you are into DIY you can buy the kit from Tubes4hifi and upgrade components yourself. Otherwise you can go to Don and get his version.
Following up @charles1dad comment, I too think a comparison between Don Sachs and Linear Tube Audio (LTA) ZOTL preamplifiers would be very interesting indeed. As a side note, the Tube Research Lab (TRL) Dude is another 6SN7-based design
After exchanging a few emails with Don, I got the sense that he is not only quite knowledgeable and generous with his ideas, but he’s also a very modest guy … a real professional. At the same time, I had hoped he might weigh into the discussion regarding any similarities/differences between his approach and ZOTL from a technical perspective. In the end, I suppose all we really care about is “how does it sound?”
Having just read Teajay’s (Terry London) Home Theater review of the LTA MZ2-S line stage, all I could say is “wow”. What I found particularly compelling was his comparison to the Van Alstine AVA FET Valve CF, along with a host of other well-known and much more expensive preamps. On the other side we have @whitestix experience with Don Sachs’ SP-14 outperforming an equally impressive line-up. Wouldn’t it be great if someone (Teajay?) could get a hold of both units for a head-to-head shootout and review?
In terms of features – and just looking at the MZ2-S - Teajay goes on to list a few High Points and Low Points in his review. Based on what I would consider for my own purposes, I’d go a step further in comparing the SP-14 versus the MZ2-S: 1) The MZ2-S is multipurpose … functioning as a preamp, an integrated, or a headphone amp. So one could add a set of high-efficiency speakers and be good to go; 2) The SP-14 allows up to 6 inputs, including the ability to swap out a couple for HT pass-through and balanced/XLR. In this case you would have 4 RCA inputs +XLR input +HT. The MZ2-S has a limit of 3 inputs; all single-ended with no HT option. 3) The SP-14 has 2 sets of pre-outs to easily add a subwoofer. The MZ2-S has 1 set; and 4) both have remote control options, neither allow for built-in phono stage (like the AVA FET). All things considered, I’d opt for the Don Sachs SP-14.
These are just a few thoughts I wanted share on the subject. Thanks for reading. I hope the folks who I mentioned don’t mind. It’s just that I always try to defer to those with firsthand, or should I say “first-ear” experience. That said, even though I have not personally heard either of these preamps, I have a very strong feeling I’d be quite happy with either one.
You have raised several interesting and informative points. A shoot-out with Don's SP14 variant preamp which costs ~$2000-$2200 preamp vs. the $6000 Dude would be very interesting. As for the LTA MX2-s, it is a multi-purpose unit that will drive only the most sensitive speakers, like Klipsch horn speaker where 1 watt might be sufficient. Its purpose, as I understand, is as a headphone amp principally. Don's SP-14 is of course specifically a preamp.
You have aptly described the features of his SP-14. His tape loop, which I have, allow me to use my DSP Anti-Mode digital signal processor. I am quite certain he now offers a remote control for his preamp, as well. Don has been spending a good bit of time lately comparing the sound of various internal wiring, carefully noting the differences of between them. He can build the preamp with absolutely stellar Neotech copper/silver/gold wire, as well as the very good new Dueland tinned copper wire. The very pricey, but stunning Dueland caps are an option as well. Don will work with a customer to find out what aspects of sound they prefer and build the preamp accordingly. So, frankly, he actually offers a multitude of preamps that are tailored to the preferences of his customers.
As I noted above, I also have a stock SP-14, albeit with upgrade Mundorf silver Oil output caps, and it is very good, indeed. But Don's preamp, when compared to it side-by-side, is vastly better in every respect. The soundstage is huge and the instruments are perceived as hanging in the air with a stunningly clear presence. By comparison, Don's preamp is much more extended with more impactful bass. The improvements he employs with the basic SP-14 design are all additive and carefully thought out and personally voiced by Don.
Three final points. An integral part of Don's synthesis of the SP14 design has been to locate the tubes on the top of his preamp. This has two advantages. First is that it allows for better heat dissipation of the tubes, likely leading to longer tube life. And secondly, they allow for convenient access to the tubes for what a lot of us like to do, which is "tube rolling". Rolling tubes in the stock SP14 entails removing over a dozen tiny screws to access the innards of the preamp. I think this design improvement is sheer genius. Finally, I think the wood case that Don uses has a great deal of ascetic appeal, with the glowing tubes on the top.
So, yeah, I am a devotee of Don's preamp after having several far more expensive preamps in my system over the years. Along with Don's new KT88-based amp, one would be a outstanding combination to drive most any speakers. You could spend a whole lot more dough, but not likely not be more satiated with the performance. Cheers, Whitestix
What is intriguing about the Linear Tube Audio (LTA) ZOTL preamplifier is what it has been compared with in direct listening sessions in a familiar system. In his review Terry London match it against the Pass Labs XP 30 and the Concert Fidelity preamp driving his Pass Labs XA 60.8 amplifier. Not only did the LTA ZOTL preamp compete he felt that it actually sounded better.
That’s very significant praise when one considers the cost and esteemed reputation of the two reference preamps he’s relied on in his primary system and for his reviews. Obviously one person’s listening impressions but worthy of note given the context.