Best balanced linestage/preamp for $4000 or less ???

P.S: What is the make and model of the subwoofer?

Regards,
-- Al

would finding a preamp with direct coupled outputs solve this issue ? The MP-3 MK3 is designed this way and I see some other preamps heading this way..

The direct coupled output of the MP-3 would have no trouble driving both your amp and a powered sub, if it could be modified to provide RCA output connectors in addition to its XLR connectors. I’d imagine that in general that would also be true of other tube-based models having direct coupled outputs, but I’m not aware of any such designs other than Ralph’s. And I think the design of his direct coupled output circuit may be patented.

But there are certainly a number of tube-based designs having capacitively coupled outputs or transformer coupled outputs that would also be suitable in that respect. Offhand, though, I can’t think of any that I know would also meet your other requirements and preferences (balanced and unbalanced inputs and outputs; balanced internal signal path; tube-based; ~$4K or less).

Regards,
-- Al

@almarg  ..  would finding a preamp with direct coupled outputs solve this issue ? The MP-3 MK3 is designed this way and I see some other preamps heading this way..

Asking $3600, but pickup only

I was going to suggest a used Atma-Sphere MP-3, as Charles did, except that I’m pretty certain it only provides a single pair of XLR outputs, and no RCA outputs, at least in its standard configuration. If you can find one that you would want to consider, though, a call or email to Ralph Karsten at Atma-Sphere would be in order, to see if he could modify it to meet your requirements.

Many of the other suggestions that have been made also will not meet your stated connectivity requirements. In addition, many tube-based preamps (NOT including Atma-Sphere’s) will have problems driving the line-level input impedances of many and probably most powered subwoofers. Line-level input impedances of most (although not all) powered subs tend to be in the range of 5K to 20K or so. 20K is the lower limit of the load impedance ARC recommends for most of its line stages and preamps. Also, many line stages and preamps made by ARC and other companies drive their RCA output connectors with the same signal that is provided to one of the two signal pins on their XLR output connectors. Which means that the output stage providing that signal would be loaded by the input impedances of BOTH the sub and the main power amp, and the input impedance of the sub may therefore affect the signals received by the main power amp. In this case your power amp fortunately has a high input impedance (100K), but even so 100K in parallel with 20K would result in the preamp seeing a load impedance of only 16.67K. And 100K in parallel with 10K would result in a load impedance of only 9K.

I would have significant concern about BAT preamps as well (many of which would require, btw, that you use an adapter or transformer to convert balanced outputs to single-ended, to drive the sub). For example, while the VK-50SE has a specified output impedance of 200 ohms, presumably based on a mid-range frequency, Stereophile measured its output impedance as rising to 4600 ohms(!) at 20 Hz, which would make it unsuitable for use in driving a sub having a typically low input impedance. And the corresponding numbers Stereophile measured for the Aesthetix Calypso were not a great deal better.

I have no knowledge concerning the Backert preamps, but based on a quick look at the other tube-based models that have been suggested the only one that I suspect might meet all of your connectivity, functionality, and drive requirements is the Freya!

Good luck. Regards,
-- Al

You've conveyed features you want in a preamp, but you haven't mentioned anything about what sound characteristics are most important to you or what you'd like to improve upon over what you have currently.  You'll get much better recommendations here if you can share that info as well. 

@oem-wheels
Yes...have had one since Jan 2017. Before the Freya, I had an Opera Reference 50 pre (2-6H30 w/an EZ80 rectifier) that I actually preferred to a CJ I auditioned (can’t remember model but line stage with a pair of 6922s). In turn, the sound with the Freya was noticeably more refined and relaxed than from the Reference 50. With the gear I have (system posted) I find music to be nicely detailed, good soundstage, non-fatiguing. I use the Freya with 3 different amps: Taranis, Hegel H-200 (an integrated but I like the flexibility of the Freya so use the Hegel in power amp mode), and First Watt F7. I really like it in JFET buffer mode for the higher power amps; tube mode with the F7 (need the gain). I’m sure better is out there but I feel no need to rejoin the hunt or spend more $.

I don’t know what your listening tastes are like or how it would work with your gear. I do think it’s a high value piece. Would cost you $35 (5% restocking) plus shipping to check it out. You might hate it but at least you will know. Hope you find something that sounds good to you. Good luck in your search.

You may want to look at the Aesthetix Calypso.A great sounding preamp that can be found used for under $4K. I believe it's $5K new.

http://www.aesthetix.net/calypso.php

I would be very curious to know what you think of the Freya if you try it. I have a Saga and I think it sounds fantastic. Super low risk to try, and I would be surprised if you returned it based on my experience.  I wish I had a few different pre amps to switch out and compare, but I’m confident it’s good.

Check out on ebay Accuphase C- 250. Directly from Japan with free shipping and make offer.
You can simply steal...

the Atma-sphere MP-3 , Backert Labs , Freya looking real good to me ... how much you asking for the BAT33 ?

I HAVE A BAT 33 PREAMP MINT IF U R  INTERESTED..

Go with the BAT either 52se or 42se tube or ss I've owned both and they are great, quiet, and reliable.

I know "best" is subjective.. I just meant a real good one that someone really liked above many.. Used stuff is ok with me..

Spectral and Ayre are transistor and OP expressed desire for  tube preamplifier.  A used Atma-sphere MP-3 is excellent in terms of the sound quality, built quality, reliability and customer service. A very compelling component. 
Charles 

Best is subjective but Conrad Johnson is a good place to start. Great value. The highly respected classics from BAT, ARC, VPI, Mcintosh and EAR (and several others brands) come with a commensurately high premium price tag....probably out of your price range.

Don’t know about "best" but pretty darn good. Consider auditioning a Schiit Freya. $700 bucks new with a 5 year warranty. 15 days to make up your mind. Run signal to it 24/7 for 10 days. You’ll have 5 for critical listening. If you keep it, replace the stock tubes (probably advisable; stock tubes can be noisy) with some better NOS 6SN7 options. Has 2 pairs of single-ended out + 1 pair of balanced out (all outputs always ’on’). Two pair balanced inputs + 3 pair single-ended inputs. High quality, resistor-based stepped attenuator for volume control (128 steps). Can run as pure passive, JFET buffered or tube mode (14 db gain). Very responsive to wire changes and very, very quiet even with very affordable new production EH 6SN7s. You can always spend more if you must but definitely worth a listen.

I can highly recommend a Backert Labs Rhumba preamp; I use one and its is a great piece!

https://www.audiogon.com/listings/lis8ihb0-backert-labs-rhumba-1-2-tube-preamp-preamplifier-tube

This one 😄

http://www.libertyaudio.com/products/b2b-2-line-level-preamp-dac

From its maker

good listening

Peter

See if you can find a Ayre K1xe...I think that's your money ball park.

Good good plan. Tube pre and SS power. You can go as sweet as you like.

Grab a used Spectral Audio preamp. Musical,clean,detailed and dynamic.