Preamp... Solid State or Tube

I am looking for 2-ch preamp that must have HT bypass option to mate with my existing HT processor.  

My budget is 10K for this upgrade.  Couple of preamps comes to mind but I have no experience with these components.  

Ayre KX-5 Twenty
Aesthetix Calypso 
My system consist of following components, 

Speakers - B&W 800D2
Source - Aurender N10,  Modwright Elyse DAC, Raysonic CD-128
Amps - Modwright KWA150SE (Pair of them being used in bridge mode)
Processor - Krell 707
Cables - Verastarr Grand Illusion Statement and Signature series

Any recommendations will be highly appreciated. 

Abc875d5 dd7e 46b7 9d49 3e8463938063lalitk

I've never heard the Ayre pre you're considering, but I did own an Aesthetix Calypso for a while. 

You might want to look into Modwright preamps.  They are spectacular and should do well with your power amp (and dac).  While well below your stated budget, I picked up an SWL 9.0SE and was stunned by how good it was - I find it FAR superior to the Calypso.  If you're planning on spending up to $10k, I would think looking at some of Dan's higher end pre's would be worthwhile.

Definitely consider the ModWright LS36.5 DM. I have a recent LS36.5 and couldn't be happier. After some tube upgrades; Synergetic Black fuse, WyWires PC and Daedalus DiD's I'm not in such a hurry to send it in for the DM power supply upgrade. It's a great preamp. I moved from a SWL 9.0 SE and that is a fine preamp but it's not as refined as the 36.5... really not even close. Really enjoyed my 9.0; it had great PRAT. The 36.5 has the PRAT too but it is so much more open it doesn't stand out as much. I'll eventually send my 36.5 in to become a DM because I'm sure it is a nice improvement. Dan's a great guy to work with. 
The Modwright preamp should mate well with your Modwright amps, and they do have the required HT bypass option. I would lean towards the LS100 over the LS36.5 because I like the 6SN7 tube better than the 6H30, but obviously your tastes might vary.

I'd also recommend a VAC Renaissance Mk III as a second option.
It also has the HT Bypass mode and sounds incredible.

How about this:

You'll probably get it cheaper & spend the savings on a loved one...!!
No doubt the Modwright LS-100 should be a top consideration, with the 150SE amp. As I understand, the difference between the LS-100 and the 36.5 is the latter is a bit more refined sound  and the former has more warmer tube sound. So it is becomes a matter of taste to which one fits your needs.

I have the MW 150SE and the LS-100 in my system and am very satisfied with its sound.
@adg101,  can you elaborate on your experience with DiD's?  I have been on fence to try isolation devices with my DAC or CD player.  All of my equipment are housed in a customized component rack that is preloaded with damping materials to create a high mass, low resonance core.

Back to preamp, I am looking for fully balanced circuitry from input to output. Both LS-100 and 36.5 are nice preamps but they are single ended design.  

Until Dan comes out with a fully balanced Linestage, I would like to explore what else is out there. 

I can see why it would make sense to go with MW linestage since I already own MW's amp and DAC. IMO, balanced circuitry yields much better overall sound. 

Thank you all for your feedback. 
@jmcgrogan2,  I never heard of VAC until now.  And I am quite intrigued by their Statement Line Preamplifier.  Too bad, I can't afford it :-)

Tube preamp solid state amp best sounding combo.
@ebm, I concur with your assessment of tube preamp/SS amps. However, I am skeptical about mating a tube output DAC and CD player with a tube preamp.  

Pardon my limited experience with tube gear, I Don't wanna get stuck in the vicious circle of tube matching between components. 

@lalitk - are you running very long IC's?

if fully balanced is a must, perhaps take a look at Atma-Sphere.  no HT bypass, but that's easy enough to work around... just run the main outs from your Krell processor to any analog input on the preamp and set the preamp to the same level (12:00, 3:00, unity, etc) when using the processor.  HT bypass is nothing more than a means to bypass the volume control in the preamp, effectively passing the signal with no attenuation.

ModWright LS100 is definitely not a balanced preamp. The LS 36.5 is balanced; not a balanced circuit but Dan uses output transformer to convert to a balanced signal; just his way of doing the same thing. The reason I went from a SWL 9.0 SE was because of my Pass amp was noisier than I would have liked and the 36.5 solved the noise issue running balance. The LS 100 I believe has XLR jacks and is just a cheater; same as if you do it with interconnects. Again that is not the case on the 36.5.

The LS 36.5 with its stock tubes is very good but I would agree sounds like a great solid state preamp, but you pull out the Sovtek's it comes with and things change. I'm running a NOS Mullard GZ34 and Cryoset EH 6H30pi's. With this combination it has transformed the LS 36.5 to another level; still not overly tubey but that's not what I wanted. I will add I threw in a Synergistic Black fuse and that was huge. My LS 36.5 is so revealing, open and musical that I enjoy listening for hours at a time. It's a fantastic preamp and I can't even imagine what the DM power supply adds to it. I wouldn't be surprised if how I have my single box unit running it wouldn't give the two chassy a run for its money.

I spoke with Dan about changing out the fuse and he said to try the Daedalus DiDs first as he didn't feel fuses change things much. I'm guessing he hasn't heard the Synergistic Blacks because it was huge. Anyway I did try the DiDs first and oh my they are fantastic. I took them over to my Dads system and he was floored as well on his Sonic Frontiers Line 1. The change was the same on his system as mine. Cymbals, piano and strings just resonate like there's no tomorrow. Things really opened up the space between instruments became better defined and tight but not at all sterile. Right now I only have the one set which I run on my LS 36.5. I will be getting another set for my CD player but added the SR Black fuses there first. 

I bought my DiDs from Dan and if you have bought any of his equipment he gives a nice discount on the DiDs and if you don't  like them I'm pretty sure he'll refund your money back.

As far as if the LS 36.5 will not be compatible with your other MW gear I wouldn't worry about that. I've never read anyone having a system match problem with it. I ran it over to my Dads system when I first received it and it sounded great on his ARC tube amp. 

If you are really happy with the rest of you MW equipment then the LS  36.5 is a no brainier and if you want to spend up you can always do the DM version now or later. I bought mine directly from Dan as there's no local dealer and he was great to work with. Pretty sure if you don't like it he will let you return it but I bet you don't.
Krell Illusion II
Tube vs. solid state is irrelevant at the price point you're considering.  The only thing that matters is impedance matching. 

At $10K, the selection is pretty wide open.  My favorite and the favorite of many others is the Herron Audio VTSP-3A(r02).   I can't recall hearing anything I thought equaled it.  It does not sound like tubes, nor does it sound like solid state.  Not warm, not dry.  Vanishingly low distortion.  Extremely clean and detailed.  IMO, it doesn't have a sonic footprint nor does it impose itself on the signal.  It's just very transparent and true to the source. 

I own one.  I'm convinced. 

I would not hurt to call Keith Herron directly to discuss your system.  He is very open and honest.
Gotta be tubes for me. There some new preamps on the horizon from PS audio and the one from Decware I just preordered will be out in a couple of months.

I have Steve's CSP3 and love the sound for a relatively inexpensive pre but wanted a true balanced. A minimalist design, no circuit boards and he will put a HT bypass in if requested.

There's great tubed pre's and theres great solid state pre's . To say only one will do is just stupid . Wake up !
It comes to what do you have for a amplifier and how detailed it is 
I have been doing this for 40 years and In my opinion a great vacuum tube pre amp complements the Solid state you get better image depth and more dimensional  with Vacuum tubes.
Leading edge detail will be more defined with solid state preamp.
Also type of tubes makes a huge difference also
Budget has the biggest factor Coincidence has a great preamp 
For under $6k these tubes  were designed by Western Electric 
And refused to license to Anyone the A 21 tubes I believe that is the number are very natural. This is just my opinion and a solid example.pass labs makes a nice one Reno aufio sells used that are excellent.
@lancelock,  the ZTPRE definitely peaked my interest.  Loved the high rev video :-)

What is the retail? However I feel, three inputs leaves very little room for any future expansion with one input occupied as HT bypass. 

@bpoletti, good recommendation. But I am not considering any single ended preamp. 
Agree, but who said one is better than the other? Isn't everyone just stating what they have or have experience with? No doubt when you start spending this kind of money there are many great SS preamps. I came real close to buying a Pass XP10 which is a fine piece. For 10K I'm sure the XP20 and other SS preamps in that range are to die for. Funny how everyone describes these great SS preamps,  they often refer to how close it sounds like tubes... same with amps. Best bet is listen before you buy, and if that's not an option talk with the designer and chances are they will sale to you direct and refund you if you don't like their product. 

There's both great tube and SS amps as well, but for my money and taste I prefer SS. I enjoy tube amps a lot and have heard a ton and have owned them as well. I personally don't want to mess with the cost and maintenance of retubing an amp. For the most part; retubing a preamp isn't too costly and tube life is far greater.

Everything listed on this post have been great options and I bet most of these companies, when you call the owner is probably the one answering the phone. You'll have to eat some shipping cost but I'd call them and demo the ones that interest you and see what happens from there. 

Good luck
My last post started to response to maplegrovemusic post above
@adg101, I appreciate your insight on DiD's and thank you for your feedback.


the ZTPre has an introductory price of $3735 and will go up soon after. You can also audition for 30 days and return.

 Another vote for Modwright. I tried the LS 100 and 36.5 and the latter was clearly better. I also tried an ARC Ref 3 about the same time and preferred the 36.5 at a good saving.

 The two box version of the 36.5 is a clear step up to the one box version. Unfortunately, the dealer told me you can not upgrade from the one to the two box version. I would love to hear it against the ARC ref 5SE. It is about £2000 cheaper than the ARC, in the UK. I suspect it is better or at least as good. I have heard both, but not side by side. I run the 36.5 into the ARC Ref 75SE, but I have run tube Pre's into SS Power units in the past and very much like the combination.

Back to preamp, I am looking for fully balanced circuitry from input to output.
You've not mentioned if you need a phono section.

Our MP-3 (which is fully balanced-differential and all-tube) would fit the bill and is known to work quite well with the Modwright amps. There is no HT bypass; you merely set the volume control to a particular position (which is essentially what the HT bypass does) and you are good to go.

Lalit, a point to keep in mind is that the input impedance of your Modwright amps is specified as "Min. 15K at 50Hz; 23K at 1Khz."  While it's not made clear in the manual if that applies to the unbalanced input or the balanced input or both, some tube preamps will not perform at their best when driving impedances that low.  Including the Calypso you mentioned in your initial post.

Atmasphere preamps, however, will certainly have no trouble dealing with such an impedance.

Good luck.  Regards,
-- Al
Are your plans to pick a preamp sight un heard and never look back ? If not just start the process . If you are going used the market availability will decide your options . One full proof way of getting a match is to first go with same brand as your amp . Or just see if one brand comes up more than others here ? Great way to pick a component !
Almarg: Can you describe the impact on the sound of using a higher input impedance amp such as the Modwright and a linestage that would like to see less impedance?
....sorry, I meant LOWER impedance amp.....
@lancelock - thank you for the info.  

@almarg - I am seeing great recommendations all around.  Since I can't possibly try them all, I am thinking about visiting AXPONA 2015 next month and check out some of the aforementioned gear. 
Dodgealum, first let me digress for a moment and compliment your very fine system. I would especially commend your taste in speakers, phono stages, and cartridges :-)

But to address your question: The issue that most commonly arises when using a tube preamp (which often have relatively high output impedance) in conjunction with a solid state power amp (which often have relatively low input impedance) is that most tube preamps have coupling capacitors at their outputs which result in their output impedance rising to much higher values in the bottom octave or two than their output impedance at higher frequencies. The interaction of that output impedance variation with the relatively low input impedance of many solid state amps will result in some cases in perceptible rolloff of the bottom octave or two.

For example, John Atkinson’s measurements in the Stereophile review of the Calypso indicate that the output impedance of that preamp’s balanced outputs (which are presumably the outputs Lalit would want to use) is "112 ohms at 1kHz and above, this increasing to 3900 ohms at 20Hz due to the finite physical size of the output coupling capacitors." The interaction of the combination of that unusually wide variation of impedance as a function of frequency (unusually wide even for a tube preamp), and the very high 3900 ohm value that is reached at 20 Hz, and a 15K amplifier input impedance certainly figures to be problematical, especially if the speakers (or sub, if present and not driven from a **separately buffered** preamp output) are capable of reproducing a good deal of the bottom octave.

A high output impedance will become somewhat less critical of a factor as the amount of its variation over the frequency range becomes less. And it may not matter at all if the variation is relatively small. But to assure optimum compatibility, the rule of thumb guideline (as properly stated IMO, which it often is not) is that the input impedance of the destination component should be 10 or more times greater than the output impedance of the component providing the signal, **at the audible frequency for which that output impedance is highest.** And if only a nominal output impedance is known, such as at 1 kHz, and there is reason to suspect that the component uses a coupling capacitor at its output (which most tube preamps do, Atmasphere’s designs being a notable exception), a much higher ratio should be applied to the nominal value, such as 50 or even 75x IMO.

The output impedance of your Herron preamp is apparently specified only at 1 kHz, but that value is fairly low at 100 ohms. 100 ohms is 150x smaller than 15K, and therefore whatever impedance it may have in the bottom octave is unlikely to be high enough to be an issue with your KWA 150SE.

Best regards,
-- Al

P.S: One more point is that I wouldn’t be surprised if the input impedance of the KWA 150SE is only half as much in the bridged mono mode Lalit uses as in stereo mode, since in bridged mono mode a single input signal is internally routed into both amplifier channels. If that might matter with a preamp that is being considered, obviously Dan Wright would be the one to ask.

-- Al

Al, That's something to think about.  I will reach out to Dan for clarity.  
David12,  the MW LS36.5 can be upgraded to the two box DM here in The States. It has to be sent in to ModWright as it is an extensive procedure. Unless something has changed I know Dan does offer it as I spoke with him on the phone when I ordered my unit. You being in the UK it likely would be too expensive to send it back so maybe it's not an option across the pond. I'm sure eventually I'll send mine into Dan but for now it is sounding great with the little tweaks and tube options I've done.


Thank you for providing such a detailed and lucid response. This is why I love the A'gon! My enjoyment of music and audio go back 40 years but I've not schooled myself in the technical aspects of this hobby. There are so many folks on here that have so much knowledge and wisdom to contribute and I'm grateful.

Vac will work great!!!
Impedance matching is a no-brainer. It's (at least in the case of tube preamps) the values of the output capacitors. 50k is way too low for tube amps, which run in the mid- 250k-ohm range. Fifty should do you fine for a s/s amp. Coupla solder connections and you're good to go, and probably upgrade the caps that are in the retail pre-amp as well. Murndorf silver-oil or gold-oil are the best.
After 45 years as a stereophile there are only a handful of preamps on my short list. And at the top of the list is Ken Stevens CAT SL1. His all tube with outboard power supply has the features you are looking for and be had 7995 line stage only or 9995 with an incredible phono section. I hope this helps!

The Manley Shrimp and Jumbo Shrimp are nice tube preamps with very low output impedance and reasonable (11.8db) gain. I have a Shrimp driving my new Firstwatt F7 which has 10kohm input impedance, quite low so my tube preamp options were limited, especially for the budget ($1k used) I had in mind. 
Maybe take a look at Backert Labs Rumba or Rythm pre amps. Also look at Zesto Audio. They too have tubes. 

For solid state, I'd suggest a Classe' Sigma SSP. It can do both surround home theater and two channel. It has a great interface and can be controlled via iPad and iPhone. 

McIntosh C1100, your search is over!
@sergiohm, Looks like with C1100, McIntosh thought of (almost) everything. The decision to exclude decoding of high resolution digital formats – including DSD files is beyond me at this price point.  

At $13K it's out of my budget, but it definitely begs an audition even if I can't afford it :-)

There's too many nice sounding preamps to own anything but a few of them. I've owned a Threshold T3, a Threshold T3i, a BAT VK5i, VK30, VK40, VK20, Forte 4A, Coda 04r, 02, 01p, ARC LS5, just for starters. I preferred the BAT pre's the most, and The Threshold's next, but they were each fabulous sounding preamps, all mated to SS amps from Plinius, to Pass, BAT, on and on. Now I own an Inspire LP2 mated to an Inspire fire bottle KT88 set amp by Dennis Had. So much gear, so little time and money. Over 20 years I've only owned a few products I didn't care for, one being an ARC LS8 I believe the model wasn't here long enough for me to remember the model number...enjoy the listening journey.
I have seen very little feedback in this post about the two pre's you asked about.
I currently own a Calypso in my system , running a direct-stream dac and transport, Mcintosh M1.2 mono amps with Legacy Whispers HD's using AMT version all fully balanced.
For my ears i have not been more pleased at this price point. I have been to a lot of shows and auditioned many B&M stores and have only a few systems similar to my current experience and i must say at a lot higher investment.

I also run HT thru my gear and the Calypso performs flawlessly in two channel and HT. I have performed several different tube rolling efforts and found that it depends on your ears preference to decide tube type.
I an planning on upgrading to the Signature version soon which from what I have read and hear from the community reveals another layer of depth and openness that i find really hard to believe exists, but that is the ghost that this hobby keeps us all chasing.

At your listed price point I would suggest that you may consider a MBL 6010D preamp, occasionally you can get close to this price on Audiogon and IMO this is the pentacle that pre's have to offer, so much to offer although solid state, I had the pleasure of auditioning this pre was so revealing it made you want to take off your shoes and just wiggle your toes, I'm really impressed with this piece of gear but it is far beyond my budget limits, and there will be no need for tubes and other maintenance requirements with this gear.
I'm sure you are aware Aesthetix also has many higher level units, the Calypso is only the entry level.

I have also auditioned Convergent Audio gear in my system as well, this brand needs no introduction, but only offers rca as a standard , you can gat balanced upon ordering.
I also performed an AB comparison to the Calypso and the SL1 MKll they were surprisingly close to each other almost no difference in presentation , for the money the Calypso was my choice and I have been extremely happy with this choice.
I think the suggestion about attending the Axpona show was a very good idea,  Modright is always there,  The amount of feedback you get at these shows are priceless though,  good luck on your quest to getting as close as you can to real thing.

Besides being one of the greatest preamps ever made regardless of price,  CAT SL1 Renaissance can be had with a unique HT bypass mode. It works with the preamp in off mode so you do not burn the tubes. Let me know if you wish to discuss. 

Dealer disclosure 

You got a very nice system and thank you for your feedback.  MBL 6010D is indeed very nice, may be someday.  Based on the general consensus here and my personal experience with Modwright, I am likely to end up with a Modwright tube preamp.

I think their Elyse DAC is still flying under the radar. Strangely it doesn't garner enough press. IMHO, it's one of the most natural, relaxed and tonally accurate sounding DAC available under 10K price point. 

Hopefully down the road, we get to see a Modwright all-tube linestage with fully balanced circuitry from input to output with HT Bypass and XLR inputs.  

I heard rumblings of all new SWL 9.0 Anniversary Edition preamp around $3K. It will be a 5687 based single-ended line stage of all-tube design, with choke-regulated supply, Home Theater Bypass and integral headphone amp. Fit and finish will be similar to the original, i.e. heavy gauge with a 3/8" aluminium faceplate with engraved lettering to match the existing product line. 

Happy Listening!