[GHM]

Hi Guys..yes this is the MPX3 Slam made by Mikhail Rotenburg. It's kinda funny. Mikhail meant to send me the MPX3 with the extra set of outputs but sent me the one with an extra set of inputs. So he had me to connect a RCA adapter with stereo rca outputs and use the phones output  of the headamp.

I was thinking before I did this "This thing won't sound that great using a cheapo radio shack adapter". I was wrong big time!!!!! It makes me wonder how much better  it will sound if it had the dedicated outputs and one volume pot bypassed.
I ask him why it sounds the way it does. He said because of the Plitron transformer upgrade for one. He also told me this unit is very powerful.Powerful enough to actually drive a pair of small speakers if configured in a certain way.

Looks like it will be a while before I get my unit now. As I've had him alter the plans a bit. He's thinking of adding a third tube to my Tubey EQ and building in a bypass switch for the tone controls.This way I can take them out of the path completely. Because I don't need them accept on really bad recordings. I told him I wanted the mix of the 6SN7 and the 5687 tubes. I believe it gives you the best of both worlds. 6SN7 tone and 5687 slam and lighting fast transients.


Paul too bad you or I don't live closer together. I could guarantee after I plug this thing in your system.You would be trying to figure out a way to get one in the system in less than an hour. There's no substitute for true clean abundant linear power at the moment.

[chadh]

GHM,

Just wondering if the tubed eq/buffer stage had arrived yet, and if you could offer any details.  It sounds as though it's an EQ thingy thanks to some tone controls you intend to use on less-than-stellar recordings.  As a buffer stage, does it offer volume control and input selection?

I use the CI Audio VMB-1s, and I keep dreaming of what I'd like in a line stage.  Dusty makes a passive linestage, and the gaincard and audio zone chip amps come with passive volume controls.  But I'm a little skeptical about passives.  Comments about the synergy between the modwright linestage and the patek chip amp make me think that a tube linestage would be a good option, but the modwright unit will be out of my price range.  A buffer stage with volume control sounds like a good compromise, though.  Decware has such a beast (the ZSLA-1), which sounds interesting.  So I was just wondering where you found your inspiration for such an item, and why you opted for the singlepower unit over any others.

Thanks,

Chad

[GHM]

Hi Chad...I haven't recieved the EQ tubey as yet.
When it's all done it will be more of a gain stage with tone controls that I can bypass with a switch. Most likely the gain will be set at a given level to match my passive volume control. I'm still playing with the MPX3 Slam which is a killer beastie.Anyone not thinking a preamp doesn't enhance bass and transients haven't heard a good linestage.

This is a test unit for me to see what sound I want from the EQ tubey.So far it's got exactly the sound I'm looking for which is fairly neutral. I picked Single Power because Mikhail designs headamps. He has to be very cautious about noise. As it is easily heard through headphones. Also I wanted something built exactly to what I wanted in sound. That's all this guy does is build units to the customer's liking.

My unit will have only one input and one output. You can have yours designed any way you wish. Mikhail has also design tube inserts for his amplifiers. This way you can try different tubes in the same slot by just using an insert. For example I could buy inserts for 12au7 type tubes and use any similar in this unit with the added inserts in any postion to listen for differences. The inserts aren't cheap $200 a set but it's better than buying another amplifier when you can just change inserts to a particular type of tube and use the same unit.From what Mikhail tells me all his units are designed to use these new inserts. So skies nearly the limit on what tubes you want to play with..that and your wallet.

Also you're correct about the passive controls. Most sources just don't have the balls to replace a linestage or gainstage. Without it the music is thinner.The stage adds more body and snap because the source sees no load and can work more efficiently instead of doing the double duty of loading the cables and the amplifier.

Definitely go for a tubed preamp or gain/buffer-stage in between your source and gainclone or what ever amplifier you decide to use. It makes a HUGE difference in the music.

[chadh]

Thanks.  Much appreciated.

Chad

[JLM]

chadh,

I'm waiting to get into the VMB-1 boat (thanks to Tom Z.) to run with my FTA-2000 speakers.  The VMB-1 like all chip amps are supposed to synergize well with single driver speakers, they should be well matched in terms of power, and they also have 32 dB of gain to go along with the CIA passive pre-amp (so hopefully enough to make up for the weak 1 volt rms Squeeze Box output).  After room treatments, my audio budget will be shot for a while.  But that will give GHM, DMason, Richard, and others around here time to report back on their "tubing" experiences.

[chadh]

My speakers aren't quite as sensitive - I'm using Von Schweikert VR1s, with 89 or 90db sensitivity.  But still, with my active pre, I currently struggle a little with too much gain.  I've coped by using Rothwell's attenuators on the IC's going into the amps - but eventually I hope to move to a better solution.

Regardless, for someone like me who has never owned tubed equipment, this all sounds like fun.  I've wasted inordinate amounts of time looking at alternatitives.  I have a few constraints, though (other than the obvious financial one).  

I need to maintain a good headphone option.  My current pre-amp is really a head-amp (the Sugden headmaster), and I'd be loathed to take a step backward in headphone experience.  So, I could simply add a pre-amp, and keep the Sugden for headphone listening.  But this means that the pre-amp would need two sets of outputs, as well as two sets of inputs (for the SB2 I'm using as a source and the DVD/HT source).

Alternatively, I could go for another pre/head-amp (with at least two inputs).  But performance would have to be good in both roles.

The third option would be to look at a tubed buffer stage, and see if I could get this fitted with input and output switches.

I've been combing threads and have come up with these alternatitives:

1) Singlepower PPX3-6SN7 (with extra inputs and a set of pre-outs);
2) Singlepower tube buffer;
3) Mapletree Line 2A (pre-amp only);
4) Mapletree Ear++ (different tube complement)
5) Eddie Current HD25;
6) EAS EA3 (pre-amp only);
7) Space Tech pre-amp (pre-amp only);
Space Tech  tube buffer (could even get a headphone jack in this- but I don't know how it would sound).
9) Decware ZSLA-1 tube buffer;
10) Decware CSP pre-amp (different tube complement);
11) Minimax preamp (pre-amp only...and different tube complement)
12) Melos SHA-1 (don't know what tube complement goes in here).

Any others that I should think about?  Any obvious favourites among this list?

Chad

[JLM]

The Decware house sound is 9 pin lean compared to the fatter, tubier sound from most of the others on your list.  The impression I get is that the Mini-Max may not be the same league as the others.  The Mapletree and SpaceTech stuff just doesn't physically appear to be as well built as the SinglePower.  Don't know jack about the rest.

[carusoracer]

The Decware house sound is 9 pin lean compared to the fatter, tubier sound from most of the others on your list.  The impression I get is that the Mini-Max may not be the same league as the others.  The Mapletree and SpaceTech stuff just doesn't physically appear to be as well built as the SinglePower.  Don't know jack about the rest.

Try talking to Morningstar Audio. The MiniMax from Eastern Electric is a very good PreAmp. Espcially when modded and rolled w/NOS tubes

[chadh]

Thanks for the comments.

Inidentally...

The Mapletree and SpaceTech stuff just doesn't physically appear to be as well built as the SinglePower.  Don't know jack about the rest.

I agree that, from the outside, the SinglePower looks like much better construction.  But from the inside?  

I'm not looking to stir any pots here, but there was quite some controversy a couple of years ago (mostly on headfi) in which charges were levelled at SinglePower for having extremely sloppy, if not downright dangerous, internal wiring arrangements.  Sombody allegedly opened up an alleged SinglePower amp and allegedly took pictures that were universally regarded as horrific.  

I think the whole thing fizzled out, but I'm not sure why.  I suspect people eventually were so impressed with the SinglePower sound that they decided, even if the photos were genuine, the amps were worth a little risk of electrocution.

On the other hand, maybe the pictures were ultimately discredited.

Regardless, they've been around for a few years now, and I don't see reports of death or disfigurement from SinglePower use, so perhaps it was all a storm in a tea cup.

Chad

[JLM]

Regarding the MiniMax,

Just my opinion based on reviews of the sound quality compared to the rest of the list.  Overall I'm sure it's a nice pre-amp.

As Morningstar sells the MiniMax I'd expect their opinion to be bias.

[ohenry]

I somehow missed this thread earlier.  I just wanted to add that Peter Daniel has been very courteous and helpful by providing guidance as to which amp kit and power supply parts are needed to mimic the stereo Patek in function (my off-the-shelf chassis possibilities won't compete with the exquisite Patek).  I'm still amazed that he gave a little time to me as a stranger and shared his knowledge.  Of course he sold some parts to me, but relatively little money was involved as compared to his finished products.

I hope the parts get here soon to see if I can assemble something that sounds close to the real thing.  If it does, this could be very good and inexpensive.

[GHM]

I haven't seen the thread about horrific wiring ..nor have I looked for it tell you the truth. The last time I spoke to Mikhail he told me I could open the unit up and check it out if I wanted to. I haven't done this either. As it does exactly as it is intended to do without me digging inside.

I haven't heard the Decware buffer unit. But I have researched it pretty well. It really doesn't get high marks from the owners that have posted their impressions. They complain of noise among other issues. Someone ask about the CSP on Agon last week. One owner responded that it was a peice of junk..of course that's just one opinion. Srajan of 6moons did a review on it. It's one of the worst reviews I've seen him give an audio component.6moons review of the Decware CSP .



The EE MiniMax is a terrific tubed preamp.The area where it comes up short IMHO..not badly short is resolution. This is a very musical preamp and solid as a rock in construction. It smooths the music just a tad..which can be great in the right setup. It is also a little noisy when used with the Gain clones. The bass is good but not as weighty or defined as the Single Power MPX3 Slam. The Slam does cost a bit more and uses upgraded parts. I'm sure the upgraded Minimax preamp would be nicer than the stock I've played with here.

Also the highs and the midrange are more transparent with the MPX3. It has the highs of solid state with that added shimmer on top of tubes. It isn't a tubey preamp though. It could be with just a swap in tubes however. If you want to smooth over the music with a classic tube touch , the EE Mini will give you that. If you want SS highs and transparency with absolute dynamic slam the MPX3 gets the nod IMHO.

[chadh]

I haven't seen the thread about horrific wiring ..nor have I looked for it tell you the truth. The last time I spoke to Mikhail he told me I could open the unit up and check it out if I wanted to. I haven't done this either. As it does exactly as it is intended to do without me digging inside.

Actually, I just discovered that IF any issue existed with these units, it has almost certainly been cleared up.  In the old days, all the SinglePower amps were point-to-point wired, but now it seems that they use PCBs.  Perhaps this was a response to the concerns raised a while back.

Man, these SinglePower amps are tempting.

I was also trying to dig up information about the Eddie Current amps.  The guy behind Eddie Current is the same guy who used to design the circuits for Moth Audio.  The amps shown on their webpage are no longer in production - but have been replaced by other things.  It's just hard to discover what those other things are.

Chad

[chadh]

I've never dealt with tubes in my life, so I don't know anything about them.

DMason extolled the virtues of the 6NS7 tube, and GHM found this was a good option too.  But what about other tubes?

On head-fi, another head-amp/pre-amp that gets a lot of respect is the Woo Audio 3: http://www.wooaudio.com/products/wooaudio3.html

It uses one 6AS7/6080 power tube and two 6DJ8/6922 drive tubes.  Would anyone like to take a stab at characterising the nature of these tubes, relative to something like the 6NS7?

Chad

[Russell Dawkins]

If Moth Audio is the same Moth Audio loosely associated with Hi-Fi News and Record Review, I would give them a wide berth.
I had an infuriating experience in 1987 trying to deal with them long distance over some subwoofer and crossover "kit"where the crossover turned out to be a circuit board with some very sketchy instructions, including a schematic that was hand drawn on lined paper and then badly photocopied, so you didn't know if what you were looking at what was supposed to be a circuit trace or was a line on the paper!
Many expensive and unanswered phone calls later, I gave up and had to guess the answers to my questions.
I'm inclined to think this kind of grossly irresponsible business practice is less likely to occur in these days of the internet, but the name Moth Audio is still fresh in my memory.

[GHM]

I tried to deal with the guy at Eddie current on a project. We could never nail down any solid ideas. Now from what I've read about Russell Dawkins experience I'm glad we didn't!

I've seen the Woo audio around but know nothing about it. No matter what you read, make sure the power supply on anything you buy is up to par. I'm a tad hesistate of the little 100 watt transformer in these units.
A good power supply makes all the difference in the world with this audio equipment. It will make or break the performance you hear on the other end. Also buy from someone that will give you a money back guarantee . So if it doesn't workout you can return the unit without a great deal of loss ..that's if you buy new.

[JLM]

Here's some words of wisdom from an experienced tube guy I respect when I asked about adding a tube buffer/pre-amp to a solid state system:

"IMO, the 6SN7/12SN7 has just about the most natural tone of any preamp tube. It's not the spankiest or fastest, neither is it the most microdetailed. But for purity of tone and great musicality, it's a tough act to beat. It's highly linear, which is something that none of the 12A_7 family is, and what distortion it produces is nearly pure 2nd harmonic. The 6CG7 offers electrical characteristics and tone very similar to the 6SN7 in a miniature 9 pin envelope.  
 
I'm not a fan of 12A_7 anything, and do not use them except in guitar amps. Even at that, I much prefer the 12BZ7, EF86, and 6SL7, as they produce better tone. But, the 12AU7/5814 is indeed the best sounding tube of this family overall, IMO, most likely due to it's lower gain. Low gain tubes ALWAYS sound much better than high gain tubes! But if it were me, I'd use a 12BH7 instead of a 12AU7, with it's lower plate resistance and higher transconductance.
 
Have you considered the 5687? It has lower plate resistance than any of the tubes you mentioned, and has great tone with excellent speed and microdetail. One of my fave tubes. Excellent sounding black plate Raytheons and Tung-Sols are still available, and the tube is rated for a 10,000 hour lifespan. Because of it's lower plate resistance and mu, you'll get a lower output Z from it as well if configured as a cathode follower, somewhere around just over 100 ohms. If configured as a White cathode follower (current sourced cathode follower), you'll get an output Z of around 10 ohms.  
 
With a transconductance of 8500 µmhos and a low plate resistance of only 2000 Ohms, it has the necessary slew rate and low output Z to drive high capacitance interconnects and any amplifier input stage with ease.  
 
Then, there's another of my personal faves, the 12B4, which is a highly linear televison vertical amplifier triode the size of a short EL84. The sound is as neutral, uncolored, and transparent as any tube gets. Plus, they glow really pretty like few tubes do!
 
It adds no signature to the mix, and takes away nothing either. It's plate resistance is only 1000 ohms, and the mu is very low at 6.5. It has "buffer stage" written all over it. FWIW, I use this type as the power tube in the amplifier I listen to most, for about 1 watt. A beautiful tube, and dirt cheap to boot. NOS General Electrics are a dime a dozen, with Sylvanias and Tung-Sols being slightly better but slightly higher priced and much harder to find."

and ...

"5687s are a different pinout from the 12A_7 family, and have night and day different electrical characteristics from even the 12AU7, the most closely related member of that family to the 5687. You can easily rewire a 12A_7 socket for a 5687, but the supply voltage and cathode/plate load resistors values will almost certainly be different. A 5687 has a much lower Rp and higher Gm, and will need a lower value plate load resistor and cathode resistor, and usually a different supply voltage. Note that it's gain is only 18 as well, about the same as the 12AU7's mu of 20.  
 
JLM, a 12B4 makes a great linestage where you want absolute neutrality, but if you want tube sweetness/warmth, it'll not add much. The 5687 is only marginally warmer, but has a great presence and musicality, and does image very nicely. A 5687 SRPP stage is a great choice (excellent dynamics and speed), and so is a 12SN7 SRPP (excellent tone, very natural).  
 
If you can find any NOS VT-231s (military 6SN7), use them in your preamp instead of 12SN7s if you go the 6/12SN7 route. Just the one pair will last you 20 years! Tung-Sol VT-231s are especially magic, and the fave tube of my entire (quite large) 6SN7 collection."

[chadh]

I think (although I may be wrong) that the "slam" versions of the SinglePower units are made to use some combination of the 6NS7 and 5687 tubes.  It sounds as though many people find both of these tubes very attractive.

As for the Moth Audio/Eddie Current thing - I get the impression from things I've read on Head-Fi that the guy behind these operations has his genius concentrated in design rather than in marketing or production.  In the past year or eighteen months, he's released "pre-production models" of about six different amps.  Each one has been heralded with great enthusiasm from the recipients.  But none have actually reached production stage.  And the webpage mentions only amps that are about four generations outdated.  Interestingly, an amp (head-amp only) has finally reached production stage.  But all the production has been outsourced to a firm in Latvia.  (this amp is due for review in SixMoons soon).

One more question.  GHM refered to the importance of a good power supply.  Are the requisites for a "good power supply" different for a head-amp and a pre-amp?  The Woo Audio 3 is very favorably reviewed on Head-Fi, with people split on their preference between it and SinglePower amps that cost almost twice as much.  But they are using these amps (almost) exclusively as head-amps.  Does this make it less likely to identify problems with the power supply (eg the "little 100 watt transformer")?

Chad

[miklorsmith]

Dan Wright uses the 5687 tube in all his circuit designs.  That should tell you something.  I have a CDP and preamp of his and they share a fast, quiet, highly dimensional signature.  This tube is not what people think of when they say "tube sound".

The 6sn7 tube will have a higher noisefloor, and probably be somewhat less linear.  However, it produces much more of the tube-sound that brighter systems need and many people prefer.  I've not heard a 6sn7 pre, these comments are based on what I've read in reviews and elsewhere.

[GHM]

Thanks JLM for the information, this is good stuff. It looks like something our resident Tube tech(JoshK) would say. I wonder when he will start his tube gear company. JoshK seems to know his stuff! Maybe I can be a future customer.