Preamp for Pass Labs X-150.8


Looking for a good preamp to match with the Pass X-150.8 amp. Prefer new in the $2500-$4000 range, but will consider used in this range as well. More interested in tubes than SS. With or without a phono pre, as I already have a decent one but if a built-in is good can go that route as well.  Speakers are ATC SCM 19.

The new Rogues, Audible Illusions and Backert interest me. Would like to hear from owners of these units, but what else is out there?
jaybe
Of the three that you mention, the Backert Labs preamp would interest me the most. I haven't heard his new line of preamps, but I had Bob and Gary Backert do some mods on a BAT amp of mine several years ago, and the results were very impressive.

That said, many Pass Labs owners use ARC preamps. I am using a ARC Ref 5 with my XA-100.5's with good success. You may be able to find a used Ref 3 in your price range, if used is a consideration.

If only looking new, I would certainly recommend checking out the Backert Rhumba 1.1 if you can. There is a thread on polk audio where users were taking turns demoing a Rhumba 1.1.
I'm not sure if it's still going on, but it's worth checking out.


Preamp for Pass Labs X-150.8
The 150.8 only needs 1.7v in for full wattage output, and most sources even many phono stages are >2v output, so you should look for a preamp with low gain otherwise you may not be able to use much of the volume control range before it’s too loud.
Also input impedance of the 150.8 is 50kohm se and 100kohm xlr which is a good candidate for a passive preamp.
Schiit Sys http://schiit.com/products/sys

Or the very versatile Shiit Freya, 3 in one http://schiit.com/products/freya which can be used as passive unity gain, low gain tube, or low gain solid state.

Cheers George
jaybe-

consider a Pass Labs or ARC pre-amp.  Happy Listening!

I'd give the direct source  option a try and see if that suits you. The Backert  preamp Looks very interesting and promising, I suspect it could be quite special.

Charles

I'll second George's comment about avoiding preamps having high gain, and add specifically that I would therefore eliminate the Audible Illusions preamps from consideration.  The specified 30 db line stage gain of their currently produced models borders on the absurd.  Although their older Modulus 3A model had that same 30 db spec, but was measured by Stereophile as being 18 db.  Still too high, though, to be optimal with most digital sources.  And of course the disparity between the spec of the Modulus 3A and the measurement is not comforting.

The 23 db specified line stage gain of the Rogue Ninety-Nine Magnum is also too high.  The gains of the other currently produced Rogue models, and the gains of the Backert preamps, look reasonable.

Good luck.  Regards,
-- Al
 
Thanks all for the good feedback so far.

Hadn’t thought about the gain aspect so that’s good info. I sent an email to AI about their gain but haven’t heard back yet.

There does seem to be a lot of used AR pres available but either as linestage or phono only. Don’t see much in the way of the SP series. I’ve always liked the AR stuff from way back but never had a system they would fit into. Definitely on the table now.
The ARC Ref 3 is a great tube preamp.  I've been using mine with my Parasound Halo amps - great tube sound with the dynamics and bass control of SS.  

Liked it so well... I've upgraded to the Ref 5se... which is also great... but... maybe not proportionately better than the Ref 3 (guess I knew that's the way upgrades work - never that much better than the reasonably priced models).

Let me know, if you might be interested in a nice Ref 3 (mint).  
I'm curious what the downfall is of having a generous amount of Gain available at the PreAmp feeding an Amp like the Pass .8 using its balanced Inputs?

I was under the impression that if one is using an active PreAmp that it doesn't matter much whether or not you are using the majority of the volume knobs full adjustment range? I do see a potential problem if one is going DAC direct to an Amp with a 100kohm Input though since the chopping off of Bits is very likely in that case.

As an example, my PreAmp which seems to be a good match for the last 3 Amps I have owned with Input Impedances ranging from 30kohm to 100kohm via the balanced connections. The PreAmp also has a maximum output level specified at 18Vrms (Classe CP800). The Gain Range is specified as -100 dB to +14 dB and I usually end up listening with the volume at or around the -27dB mark on the display.

I will be acquiring a set of Pass XA60.8's this week so this topic is timed rather nicely as its something I've been curious about as well.

Thanks 
Post removed 
I'm curious what the downfall is of having a generous amount of Gain available at the PreAmp feeding an Amp like the Pass .8 using its balanced Inputs?
In many preamp designs if the volume control has to be used too close to the bottom of its range, as a result of excessive gain in the system, several undesirable consequences can result.  Including inability to adjust volume in steps that are fine enough (many volume controls have coarser steps near the bottom of their range than at higher settings); imbalances between channels; and degraded noise performance.

As evidence of that, there have been numerous threads here in which people have reported those kinds of problems, and been forced to put things like Rothwell attenuators in their systems, in some cases with adverse side-effects resulting.
The PreAmp also has a maximum output level specified at 18Vrms (Classe CP800). The Gain Range is specified as -100 dB to +14 dB and I usually end up listening with the volume at or around the -27dB mark on the display.

I will be acquiring a set of Pass XA60.8's this week so this topic is timed rather nicely as its something I've been curious about as well.
Preamp gain specs are based on the gain that is provided with the volume control at max, so the gain of your CP800 is 14 db.  That seems reasonable in conjunction with the gain of the XA60.8, which as in the case of most Pass amps is 26 db.  (That is a fairly typical number for a power amp).  Speaker sensitivity and the output level of the source of course also factor into the volume control settings that are used.

Best of luck with the new amps!  Regards,
-- Al


@eniac26

Noise.

We think of a preamp as a "variable gain" device, but it's actually a fixed gain device, with volume after. This fixed gain adds a fixed amount of noise! More gain = more noise.

As PrimaLuna points out somewhere, Preamps usually have way way more gain than they will ever need.

Best,


E
We think of a preamp as a "variable gain" device, but it's actually a fixed gain device, with volume after. 
I think you'll find, an active preamp is a volume control with a fixed gain stage "after it". The volume control reduces the source signal level and the output stage is at a fixed gain.
The only time there is a gain stage in front of the volume control is if it has a phono stage that also has gain.

Cheers George 
 Rothwell attenuators
As for Rothwell Attenuators, they can be hit or miss, as no one knows what  value resistors were used inside to make a voltage divider for each of the - db ratings. And they can cause an impedance miss-match between pre and poweramp, or between source and preamp depending on where they were used.

Cheers George  
Interesting thread! I've learned a few things. 

But personally, I am impressed by the Audio Research LS27, has all the features I like in a preamp, remote control for one, and I love the rear panel with both single ended or balanced on every input and output. And is right in your range used. I just bought a new (used) big solid state amp, and am just starting my search for a preamp too. Thanks guys for the great information, gives me food for thought. 

If I were in the market, my first choice for a preamp would be Linear Tube Audio MZ2-S from David Berning. Well within OP's budget with money left for accessories (and beer).
The Linear Tube Audio  and the Backert Labs preamps would be a very compelling comparison. 
Charles 
Whoops! I stand corrected!

Not including phono stages, you are correct. My bad!

I still think that most preamps have too much gain, and therefore too much unnecessary noise. :)

Erik
The ATC 19s are rated "Sensitivity is below average at 85dB/W/m". Even with the Pass amp, I'd be hesitant to use a MicroZOTL or a passive pre in this system. Cheers,
Spencer 

A lot depends on the speaker you have. A customer of ours uses our MP-1 with his Pass Labs, on a set of Sound Labs. The Sound Labs like a bit of power, so he uses the gain of his line section all the time (the MP-1 has about 14db with gain trim controls so that you can run the Master volume in the middle of its range, even with high output digital sources).

The Pass Labs amps are balanced input, so this combination seems to work well. Whatever preamp you use, I do think that balanced will offer better performance (but you would expect to hear that from someone that makes a balanced preamp, right?). So its no surprise that Nelson's own preamps are also balanced.
I was just looking at the Backert Labs pre, used AR, and a couple of others to upgrade my existing. I called Modwright and bought a 9.0 S Anniversary. I have only had it a few days now, but it is one sweet sounding pre. A definite upgrade over my Odyssey Candela.
A great smp is the PS audio, Bascom H King Signature retail  $6k underwood wally will give you s Great deal. Put the Tungstram 7dj8 tubes fantastic. 
Evrn at  $10k a great preamp with a one of a kind patented attenuator
And every review is excellent. Please note a reference grade power cord will magnify it's excellence. 
erik_squires
I still think that most preamps have too much gain, and therefore too much unnecessary noise. :)
Eric is correct, that’s why all that’s needed is unity gain (no gain) preamps these days, whether active or even passive if the poweramp is >33kohm input impedance.

That’s why the Schiit Freya is a good choice, it can be, passive, low gain tube, or low gain solid state with Balanced or SE connections. You can have it all and choose what mode sounds best for you for just $699 refundable if not happy.

Cheers George

Look at the CJ ET5 spend a little more and get a wonderful sounding preamp I'm using it with PASS 350.8 sounds unbelievable.
ebm

what other gear including cabling, is in your system?
First Sound 

pretty much any version 

US produced, vacuum tubes, external power supply(s), dual mono, upgrade able, as good as any pre amp on the market, period 
Looking for a good preamp to match with the Pass X-150.8 amp. Prefer new in the $2500-$4000 range, but will consider used in this range as well. More interested in tubes than SS. With or without a phono pre, as I already have a decent one but if a built-in is good can go that route as well. Speakers are ATC SCM 19. 

The new Rogues, Audible Illusions and Backert interest me. Would like to hear from owners of these units, but what else is out there?
I am running an Ayon Eris with my Pass X150.8.  It is prob out of your range a new, but if you can get one used it is a match made in heaven.  Actually I think any decent pre based on 6H30 tubes would be good - I think ARC may use those.  I have not heard the new Rogue pre-amps but if their power amps are anything to go by they have to be good too.
A tube preamp with 12 db gain would combine the best of tube and SS is the Wyetech Jade which is in your budget range stated since it's on sale at the moment