Preamp for Pass

I have a ARC LS26 preamp, but thinking about trying something else, but still a tube preamp.

I have tryed the DIY Tram II witch was fitted with duelund compoens and others opgrades. that sounded great from the midrange and up, but lacked some in the bass, compared to my LS26.

So witch tube preamps are great with Pass?
Try the Canary CA900. My friend is using one of them with a set of XA 160.5 Mono Blocks with great results. I believe he has a source of getting those pre-amplifiers. He is here on audiogon under the username Truesoundworks,

What do you want out of your preamp? What isn't the ARC giving you? Any musical genres you prefer.
From the low midrange and down, it is just fine. but i`m missing some extenctions in the top.....
i'm in the same mode, more or less, though not looking so far up the food chain as the Canary . . . any thoughts on the modwright 9.0 se vs. the pass labs X-2.5 matched with a pass amp product (something like the first watt F-4, for instance)?

only negative i've seen w/regard to the 2.5 is mildly hissy . . . natural inclination to stay within brand, all being equal, but the modwright seems really strong.

i am not in a situation where any real auditioning is feasible.

Which pass is it? I would think the modwright would be a sideways move.
I owned the modwright with a pass x150. I enjoyEd
Which pass is it? I would think the modwright would be a sideways move.
I owned the modwright with a pass x150. I enjoyed the combo. Using a supratek preamp with it now. Warmer sounding. Modwright is an excellent preamp but so is your ARC preamp. I'd try other interconnects / power cords before you change preamps.
The LS26 is a nice preamp, try tweaking it as suggested by Jeffjazz, or use no preamp at all if you haven't done so.
Depends which Pass amp, a lot of the Passlabs poweramps are very low input impedance, which are not very freindly to most high output impedance tube preamps.
Do your home work first the output impedance of the preamp should be at least 3 x or more lower than the input impedace of the poweramp it has to drive.

Cheers George
George is right in fact experience has shown me the input impedance of the amp should be at least 10x higher than the output impedance of the preamp or the sound will not be right or all it could be.

Check the specs of your amp and search accordingly. Please let us know the specs of your amp and pre in terms of impedance. Very important.
I use an ARC SP-15 with a Pass Labs X350 and MIT cables throughout. This ARC preamp has a 200 ohm output impedance and the Pass 22 kohms input impedance. The ARC manual says 20 kohms min load recommended. Seems like a good match. From a listening perspective, I have loved this combo from the day I put the two together.
Can't see why the LS26 would have an impedance mismatch issue with the Pass amps, seems to be perfectly within the theoretical impedance considerations, as it has fairly low output impedance to a tube line stage (350ohm SE) - which does not mean it is an ideal match sonically, just that impedances should not be of significance in the pairing.
Atmasphere or Sonic Frontiers?
I had a Cary SP-05 Preamp with my Pass Labs X350.5. There definitely was an impedance mismatch with this combo. Very little bass and treble. Sold the Cary and bought the Pass XP-10.
Just need to know the spec on both before we can make a determination.
Whatever problems there were, it was not an impedance issue, the Cary has only a 400ohm output impedance - that should work with most any amp, even Pass' "tough" input impedances.
I am using a Bruce Moore Audio Companion IIe 6DJ8 based linestage preamp right now and it's a very nice match. My Companion IIe has upgraded wiring on a couple of the inputs along with dual stepped attenuators.

No impedance mismatch at all. My typical listening at 8' away is somewhere between 75 to 85 db's. Gain knobs end up between 10:00 and 12:00.

Hope this helps!
Sorry forgot to note that I'm using a Pass Labs X150.5.
The poster has an ARC LS26, not a Cary.
I just looked it up. If the poster is using the RCA jacks, then the ARC LS26 as an output inpedance of 20k ohms. This will be a big issue, poor match, with the Pass amp.

If he uses the balanced outs, then all is fine.
I'm seeing the LS26 SE (RCA) output impedance at 350ohms. Where are you getting the 20kohm spec?
The preamp is as told, LS26 and the amp is XA30,5.

The impedans match should be fine.
It just because i heard the Tram II in my setup for some weeks ago. And the midrange at top was so fine, transperent, open and nice to lisent to.
It was clear that the LS26 was missing something there.
I´m acctoly thinking about having my LS26 upgraded with duelund components, to see if that can help

Pierre ;-)
20kohm input impedance is the minimum recommended amp load according ARC.
Fortgo to say, that i`m using the XLR ind/out-puts
Should be fine - the XLR input impedance of the XA30.5 is 30kohm (the RCA however is 15kohm and that might be pushing it, don't know without trying it, sometimes listening overrides theory).

You're correct as I misread the spec sheet on the site I found.
I did forget to mention, that the Joule LA150 Special Edition sounded absolutely wonderful with the XA30.5 --- though single ended (no XLR which may be a non starter for some).
Just to provide a contrasting opinion, I demoed my Pass XA200.5 with the Joule LA300ME and it was a poor match in my opinion. The midrange was interesting for the first several hours, but then I found it cloying and boring. Plus, I lost the treble and bass extension, the dynamics, and clarity/transparency that I get with the BAT Rex. While I still wonder about the truly balanced and much greater power Joule LA450, the sound and build of the 300 definitely reduced my enthusiasm to pursue the next step up the line.

My opinion is that the BAT Rex is a winner with the Pass XA.5. I cannot speak to the VK52 or VK51 since I have no direct experience. I've read others who were disappointed by the Audio Research/Pass pairing, but never personally pursued the ARC Ref preamp line. Good luck.
The input impedance of the Pass can be challenging for many tube preamps, including the ARC, which was covered in another thread.

This usually has to do with the output coupling capacitor of the preamp. A few tube preamps (a very few) are direct-coupled and so don't have this issue. At least one not only has direct-coupled outputs but is also fully differential and balanced. So it is possible to have the smoothness and detail of tubes without giving up anything in the bass.
Which one? :)
The RCA input impedance of the XA30.5 is 20k. Pass originally listed it at 15k but it was tested at 20k and Pass has changed that spec on some of its literature.

On preamp output impedance: remember the spec is the "average". Just like an 8 ohm speaker is hardly ever 8 ohms across the spectrum (it could vary from 2 to 30 ohms). Some pres will be many times more than its rated spec especially at the low or high end. Try and find those specs when you go hunting.
Pubul57, both the Atma-Spheres and Sonic Frontiers mentioned above, have DC coupled outputs and are fully differential and balanced, with rather low output impedance's for tube products.
Pierre1976: So which tube preamps are great with Pass?Pierre1976:

Most Pass amps have very low input impedance Pierre, for a good match this dictates the necessity to use a preamp that has very low output impedance in the order of 100ohms will be a safe bet, most good solid state preamps will do this as they are 10 to 50 ohms. But your preference is for tube so check and double check that the output impedance of the tube preamp is in the order of 100ohms or so, before spending the bucks.

Cheers George
Balanced and low output impedence, look to BAT, VAC, maybe Einstein.
OP, what next? What are your thoughts so far in response to all this feedback?

I can telly you that i ended up with a Hovland HP200p.

And i`m HAPPY :-)