Modwright LS-100 or Pass Labs Preamp

[Guest scumbag]

I have a PS Audio Directstream Junior feeding my Pass Labs power amp. When I use the DAC on full output it gives me a lot of hiss so I have to use the low gain setting. The issue is, on that setting it only outputs about .4V which is far too little to get my Pass Labs going. Adding the right preamp will also help dynamics too. I had a Xindak Class-A preamp which I really liked but I am looking to get a few things - great dynamics / swings and perhaps a bit more oomph as well as imaging depth.

I am wondering if a dynamic tube preamp will go some way to getting the imaging part. 

I am also keen to hear whether using a ridgy didge Pass Labs preamp might bring something to the party too. I assume the preamps will be a good partner for the power amps  

I am in Brisbane on the NorthSide. I do all my listening in an air conditioned office and take excellent care of my gear.

 

 

[Gremrock]

If you can get the new Supratek Cortese to trial, you'll be a happy man. I just borrowed one, and will be ordering one as soon as I can sell my Bel Canto.

 

Alternatively you could try it ( the Bel Canto) if you want something dead quiet with balanced in/out & phono. Its technically perfect if you ask me, but the Magnus needs something to add some soul to it, I got the best sound running it with my little old EL34 amp, but now I need to get the most out of this new amp considering the $$$ I spent on it haha.

[Guest scumbag]

Would your Bel Canto Pre2p be a good combo with the Pass Labs? How would you describe it's sound - obviously it's SS - does it operate in Class-A?

 

[Cafad]

Aren't all pre-amps class A?

[Guest scumbag]

50 minutes ago, Cafad said:

Aren't all pre-amps class A?

yes, unless they're not.

It makes sense to run a preamp in class-a as the amount of heat / heatsinking / power supply and so forth does not need to so robust to output lower voltages. But not all preamps are class-A. A lot of preamps use op-amps in the output section and for various reasons, not all of them are class-A biased I believe.

Edited September 12, 2017 by scumbag
typos

[Guest scumbag]

Also, I've been doing some research on the W4S STP SE Preamplifier as well which seems to be highly regarded.

What i am looking for is:
- XLR outputs - I'm not sure if fully balanced from end to end would be necessary. It's just that the Pass Labs is all about using the XLR input to reduce distortion (SUSY)

- A remote

- Nice sound-stage with good depth. Tubes hold some appeal here after my positive experiences with my PDX DAC.

-  Macro-dynamics and good levels of energy would be preferred to play off against the ever so slightly relaxed nature of the Pass Labs. 

 

Optional but nice things would be - 

- A 12v trigger. The Pass Labs can be put into standby with a trigger. That would be good to have.

- Silver and preferably a full width component. Purely aesthetic considerations.

 

Any thoughts would be appreciated. 

 

[tubularbells]

I recently bought a Modwright LS100 with optional phono only to find out after purchase that my Audio Research Ref 150 was no compatible due to the Modwrights XLR outputs being single ended only (Ref 150 only accepts true balanced). Point is I was ready to sell the LS100 but after hearing it with a borrowed non balanced  amp (Ashley 200) and finally my Ref 150 via a outboard single ended to balanced converter (Jensen transformer) its a keeper. Really amazing sound so smooth yet detailed with imaging to die for and surprisingly cheap as on the second hand market. Im now thinking if I ever make a swap it will be the amp and not the Modwright it's that good.

[Guest scumbag]

3 minutes ago, Tubularbells said:

I recently bought a Modwright LS100 with optional phono only to find out after purchase that my Audio Research Ref 150 was no compatible due to the Modwrights XLR outputs being single ended only (Ref 150 only accepts true balanced). Point is I was ready to sell the LS100 but after hearing it with a borrowed non balanced  amp (Ashley 200) and finally my Ref 150 via a outboard single ended to balanced converter (Jensen transformer) its a keeper. Really amazing sound so smooth yet detailed with imaging to die for and surprisingly cheap as on the second hand market. Im now thinking if I ever make a swap it will be the amp and not the Modwright it's that good.

Thanks for your thoughts. The Pass Labs takes the balanced input and runs it through 2 paralleled paths for each channel. It then subtracts the difference to reduce distortion. I am wondering if the output from the LS100 would still work with the Pass Labs? I will have to write an email to the guys at Pass Labs. They are always good at getting back to you with these sorts of questions.

 

[tubularbells]

You should be ok in that scenario as it seem Audio Research are an exception to the rule given they omit the phase inverter stage in there amps.

 

As per a quote from Eva Manley (Manley Labs)

 

Quote

Most balanced gear has no problem being driven single ended but check with the manufacturer if they are going to want the negative pin 3 of the XLR grounded or floating. Transformer-coupled XLR jacks always can be driven single-ended by running HOT into Pin 2 and grounding pin 3 to pin 1. Some IC coupled XLR inputs will want pin 3 floating, others will require it to be grounded when running single-ended into it. Check with the manufacturer of your gear to see how to hook it up single-ended.

 

Edited September 13, 2017 by Tubularbells

[Guest scumbag]

This is from one of Pass Lab'l manuals - "On the XLR, pin 1 is ground, pin 2 is positive, and pin 3 is negative" and "The RCA connector's ground is in parallel with pin 1 and the RCA hot is attached to pin 2". When you run RCA's you simply use a jumper - a copper horse show shaped loop to bridge Pin 1 and 3. You get 6dB less sensitivity but the amp' works fine - albeit with more noise.

 

So the amplifiers can all accept RCA inputs with no issues so it's not a case of the amp' having an issue, the only issue is that it may not be able to utilise the super-symmetry and therefore there will be more noise as the circuitry is not able to remove the distortion due to cancelling the balanced inputs.
I've already emailed Pass Labs so we'll see what they come back with.

 

Edited September 13, 2017 by scumbag

[tubularbells]

Ahh yes I remember the little copper shorting link in the XLR inputs back when I had a X150.5 but never took any notice as I only used the RCA inputs.

[Guest scumbag]

That measly little 150watt RMS amplifier that you had running with your horns? I remember you selling that too.

[tubularbells]

Ha yeah sold almost everything since joining SNA including my soul 

[Guest scumbag]

I didn't have one before joining. If I had, that would have been hocked off by now of course.

[Gremrock]

Hey Scum (always wanted to say that without being offensive!)

 

It should match fine mathematically speaking as it has a high output voltage and low (lowish at least) impedance, along with the ability to adjust the 0db point by up to 40db or more worth of settings to prevent voltage overload to sensitive amps.

I've tried many amps and never found a mis-match issue, but always got the best sounding combo I feel running with a Pure Class A SS or Tubes.

 

I wouldn't really describe it as having "a sound" the only difference when I put it in the system between a dac with volume and the power amp, is a quieter background and increased dynamics (and of course better volume control, inputs etc).

 

I doubt its Class A technically but I really don't know, I understand it runs OPamps in the output as I paid considerable money to have them upgraded to the best option when it was at the Bel Canto factory before I got it, It runs dead cold and I can't see any heat sinks except the tiny black things on the PCB's inside the case.

 

It has balanced in/out, but is not fully balanced (few things are), has remote and is silver but doesn't have 12v trigger (Sorry can't have every feature, but it goes close.. That why every other part of my system has changed multiple times, but it hasn't yet haha)

[Gremrock]

 here you go for some pictures. Most notable, it has silver things inside it's lid. 

 

I have a message, to reply to on it, but if he doesn't decide he wants it, you're welcome to borrow it for a week or so if you're interested. (and feel like picking it up :P)

[Guest scumbag]

It certainly reviewed well - http://www.stereotimes.com/amp041805.shtml . That's a generous offer but Kingaroy could be a bit of a drive though!

 

[Gremrock]

Alternatively you can pay for postage to try it if driving isn't your thing  I'm not sure when I'll be heading towards Brisbane next or id offer to drop it off

[Whites]

@scumbag I can recommend getting a Pass labs preamp. I recently changed my preamp from a Consonance Linear 1 to an XP20 and it was a significant difference. I have a Pass Labs XA30.8 power amp. The differences I noticed are the low noise floor which which showed as separation in instruments and clarity, the music is fuller at low volumes and bass is tighter.

 

Definitely for me it has been a significant upgrade, I do now believe that there is some synergy by having the same brand pre and power for Pass Labs (not sure if it is true for all brands). You hardly ever see Pass Labs preamps for sale secondhand so it must mean something.

 

 

[Guest scumbag]

6 minutes ago, Whites said:

@scumbag I can recommend getting a Pass labs preamp. I recently changed my preamp from a Consonance Linear 1 to an XP20 and it was a significant difference. I have a Pass Labs XA30.8 power amp. The differences I noticed are the low noise floor which which showed as separation in instruments and clarity, the music is fuller at low volumes and bass is tighter.

 

Definitely for me it has been a significant upgrade, I do now believe that there is some synergy by having the same brand pre and power for Pass Labs (not sure if it is true for all brands). You hardly ever see Pass Labs preamps for sale secondhand so it must mean something.

 

 

looks like I'm going to have to start saving some coin - at least for an XP-10............

[Whites]

Yes, they are expensive. I was lucky and managed to get a secondhand one.

 

Pass Labs have just released an XP12, not sure if this is the eventual replacement for the XP10, both are still listed on their website. 

[Rob181]

Pass Amps...class A...tell what goes great with class A amps is...

 

Is The Coincident Line Stage...beautiful sound & a 3D presentation to die for...

 

http://www.coincidentspeaker.com/preamps.html

Edited September 14, 2017 by Rob181

[PorkBun69s]

On 9/13/2017 at 1:30 PM, Tubularbells said:

I recently bought a Modwright LS100 with optional phono only to find out after purchase that my Audio Research Ref 150 was no compatible due to the Modwrights XLR outputs being single ended only (Ref 150 only accepts true balanced). Point is I was ready to sell the LS100 but after hearing it with a borrowed non balanced  amp (Ashley 200) and finally my Ref 150 via a outboard single ended to balanced converter (Jensen transformer) its a keeper. Really amazing sound so smooth yet detailed with imaging to die for and surprisingly cheap as on the second hand market. Im now thinking if I ever make a swap it will be the amp and not the Modwright it's that good.

Agreed with TB's findings on the LS100.  The LS100 responds well to tube rolling too.  I run mine with an Emissions Lab 5u4g rectifier and it sounds much better than a 5ar4.  Its one of the very few preamps that mates very well with my SGR speakers.