[KappaNut]

Hello all,
I'm new to AudioCircle and I'm looking to purchase a used tube preamp.  I've narrowed it down to either a Cary SLP 98 or Modwright LS100, no phono option needed.  I'm looking to spend somewhere around $2,000 plus or minus.  I'm hoping you guys can steer me in the right direction.  The one option I like with the LS100 is a headphone option.  I'd like to hear from owners of either of the (2) preamps, hopefully with your help I can make a decision.
Thanks!!!
Randy

[wilsynet]

I haven't heard the Cary, but I did own a LS100 for a short while and thought it was pretty good.

[lokie]

You may already know this but you need to be conscientious of the impedance matching with your amp.

So... what amp will you be using? A couple of other questions are: do you like a "tubey" sound or a more "clinical" sound?

How do you listen? for ex.. loud orchestra in a big room or small ensemble in a small room. New or used?

[Ericus Rex]

There are lots of options under $2K used.  Any particular reason why you've narrowed it down to those two?

[dB Cooper]

The Van Alstine preamps all have built in headphone amps btw.

[ncblue]

Modwright LS-100. Used prices are ridiculously low for the performance. I bought mine from Dan and couldn't be happier. The headphone section is not an afterthought, and competes with similarly priced stand alone headamps. If you do decide later on a phono stage, I am using mine with a Koetsu Urushi Sky Blue and don't feel the stage is outclassed.
I've heard good things about the DAC, but have no personal experience.

[JakeJ]

Lokie is headed in the right direction.  Tell us more about the rest of your system and listening habits as well as preferences.  And yes, impedance matching is important.  The more you tell us the better we can answer your questions.

I also agree with Ericus Rex, at $2K you have a lot of options and there may be better choices dependent upon the amp you are going to mate it to.

[cheap-Jack]

Hi.

Hello all,
I'm new to AudioCircle and I'm looking to purchase a used tube pream., no phono option needed.  I'm looking to spend somewhere around $2,000 plus or minus.

So you plays CD or tape only? Why not consider a passive linestage instead of an active preamp?

FYI, I've been using my DIYed passive linestage since day one for many many years now connecting to my
tube phonostages, Blu-ray audio, DVD-audio, CD-audio players, driving my tube power amp & direct-current SS DC power amp.

IME, I have never auditioned any active linestages sound so neutral like my passive, MUSICALLY regardless of brandnames & pricetags from my years of audition experience worldwide (I am a casual sound adviser).

But it is all up to you. Sorry, I can't commened any active linestages.

c-J

[KappaNut]

My current system consists of the following amps:

Rogue Audio M-120 mono blocks that I've had reworked by Bill Thalmann @ MUSIC TECHNOLOGY, INC.
Adcom GFA-585

Speakers:

Infinity RS-1B's (M-120's power the mid/hi towers, 585 powers the bass towers)

I mainly listen to CD's and my music choice varies, Alison Krauss, Norah Jones, Classic Rock and so on.

Only reason I narrowed it down to those (2) preamps was the reviews I've read on the internet.

Any direction you can give me would be great.

Thanks!!
Randy

[DaveC113]

cheap-Jack is right, you might not need any additional gain. There are active pres with zero gain output buffers, which will make sure your sources have the capacity to easily drive your amplifiers, but this often isn't necessary either. My DAC puts out 2V RMS and has an output impedance of 75 ohms... it will drive an amp without needing a buffer easily. Most of the time, an active preamp will degrade the sound to some degree so if you don't need the gain I'd consider a passive or zero gain pre.

[cheap-Jack]

Hi.

cheap-Jack is right, you might not need any additional gain.

 Most of the time, an active preamp will degrade the sound to some degree so if you don't need the gain I'd consider a passive or zero gain pre.

I am glad Dave like me, you get the sense of less gain less distortion. It proves you have got a pair of ears that appreciate real music. Not many out there can understand & apprecaie this.

Why I've to build my own phonostages (with minimum possible gain) & passive linestages instead of buying them from the marketplace? Not the money issue. It is the sound quality issue.

Most, if not all, brandname commercial products get too much gain, way too many active stages which generate harmonic distortion & phase distortion (time delay) that mess up the music signals. I've auditoned so many hi end preamp which tagged for mega bucks in the past years & they all fall in the same trap - too much gain which screws up the music. One most common problem is - not enough headroom spaceousness. Too much gain, that's why.

Only passive, zero active stage=zero gain can maintain the very complex incoming music signal integrity.
Our ears can detect such quality.

FYI, the 2 tube phonostages I DIY built/upgrade for my MM cartridge (I am a bigtime LP vinyl advocate)
got the least gain stage technically possible - one got only one single stage & other one, a 50-year vintage brandname which I cut its 4 stages down to 2 RIAA gain stages. They both sound so open, airly, dynamic & fast as less gain, less distortion deliver better quality music.

c-J

[jtwrace]

passive linestages instead of buying them from the marketplace? Not the money issue. It is the sound quality issue.

I'm sure you have covered this somewhere so a link would be fine.  I'm very curious to know what you built.

[DaveC113]

I've always thought the idea behind an active pre and power amp is a good one, separating voltage gain and power stages, but most amplifiers have an input sensitivity around 1V RMS so they don't need an active pre.

I have a DIY Aikido active pre, but I also use it as the driver stage of my single stage EL34 SET amp, and my amp has an input sensitivity of around 20V RMS, perfect for a 2V RMS source and the 10x gain of my preamp. So my amplification system has only 2 gain stages with the preamp supplying most of the gain. This works out VERY well...

It seems like the industry has not adjusted the gain structures of preamps/amps to match the standard 2V RMS signal most modern sources put out, so most people with preamp/amp combos have somewhere around 20 dB+ too much gain, which means at full volume you're still attenuating the input signal to 1/10th of it's original voltage and listening at normal volumes is happening with much, much more attenuation. This does not make sense...

[brooklyn]

http://www.upscaleaudio.com/products/PrimaLuna-ProLogue-Three-Preamplifier.html

[Ericus Rex]

OK.  Thanks for the additional info.  I have not heard the Modwright and I have not heard the SLP98 but I have owned two different Cary preamps in the past.  I may be safe to assume that the 98 would possess many of the qualities my two Carys had.  If that assumption is correct, then I would characterize the sound of it to be very classic-tube sounding.  That is to say it should be a little flabby in the bass, a little rolled off in the treble but possessing a fabulous and rich midrange.  The main problem I had with both my Cary pres is that the sound was surprisingly two dimensional and 'congealed' (not enough separation between the instruments) and attacks were slow and flabby when compared to other preamps.  Let me repeat that the 98 may not have those same qualities/flaws.  I doubt the Modwright would have those problems either.  That being said, you have Rogue amps, have you considered a Rogue preamp?  I have the 99 and I like it quite a bit.  It is a good match with my Stereo 90 amp and should be a good match with your monos.  Another option I'd put ahead of the Cary is the Dehavilland Ultra-verve.  You should be able to get one used in your price range.  Not sure how the Rogue or Dehavilland compare to the Modwright.

[cheap-Jack]

Hi.

(1). most amplifiers have an input sensitivity around 1V RMS so they don't need an active pre.

(2) It seems like the industry has not adjusted the gain structures of preamps/amps to match the standard 2V RMS signal most modern sources put out, so most people with preamp/amp combos have somewhere around 20 dB+ too much gain, which means at full volume you're still attenuating the input signal to 1/10th of it's original voltage and listening at normal volumes is happening with much, much more attenuation. This does not make sense...

Dave, it sounds like we are on the SAME page of same mother tonge! Have we ever known each other way back though it sounds like so. We've the same mutal audio philiosophy - less gain=better music!

Yes, I think it is the audio industries' design tradition to provide (more than) adequate gain in the preamps to be saleable in the marketplace. More stages more gain can sell more money, I think so at the expense of sound quality. My big question is:- do those amp designers ever spend enough time to audition their products musically before launching them onto the market?

They all may measure great on the testbench but do they all sound as good musically????
Many designers think the standard static testing measurement used by the audio industries since day one, eg. total harmonic distortion etc, using sinewaves, are good enough to ensure a product's performance.

 But are they really????????? How come a SET tube power amp measured up to 5% THD can sound better than a SS amp measured 0.0001% THD??? I read technical papers on this strange-sounding topic.

Too much gain simply pushes the volume pot setting down to near zero - or less than 10% of the dial scale, in order to avoid overload the amps down the audio chain. This is NO good as most part of the pot resistance will exist in the signal path for the music signals to pass thru. This will affect the sound as the pot resistance now blocking the signal path also get undue capacitance & inductance on top of resistance itself as realworld resistors are not PURE resistance at all.  This will affect the sound as can be detected by sharp ears.

I have auditioned so many home systems which ALL got the same problem - volume pot had to be set low low (too much attenuation) to avoid sounding too loud. This is a very very bad sign - sonically. Too much gain which already kills the headroom inside the amp needed to provide the complex music signal passage.

FYI, the volume setting of my passive linestage is set minimum down to 11 O'clock when driven by my 2-stage phonostage & up to 4 o'clock position for my one-stage phonostage. This shows the preamp section provides excellent headroom for the music signals to pass thru into the power amp. The music sound so live, dynamic, airy & UNcompressed.

c-J

[JoshK]

I will hands down say, one the best tube preamps I've heard is the Moebius by Audiotropic.   It meets all your requirements, but I don't know if it is available or not.

http://www.audiotropic.net/Products/mobius.html

Poinz has a more up-to-date version that he has shared on DIYAudio, which I'd opt for personally.   I think his design skills are top notch unlike more big box hi-fi gear (I've studied tube design for years). 

Worse case, contract a hardcore hobbyist to build the new one for you for well under $2000.   

The above points about gain matching and all that are absolutely correct, and this preamp meets them all.  Not to be overlooked.

[Quiet Earth]

Davec and Cheap Jack,
As much as I like my passive pre (TVC), I would not recommend a passive preamp in this situation. I think those Infinity speakers are going to need all the gain he can throw at them, especially since he is bi-amping. Plus, there is no headphone jack in a passive.

Both of the preamps Kappa mentioned in the first post have a 600ohm output impedance, so I don't see a problem with trying either one if that's what he has his heart set on. Hey, that Modwright looks pretty nice for 2k. I would probably choose the Cary though.

[JoshK]

Here is the thread with the updated Moebius I was referring to, using 6T4 tubes.   I'd be confident to put this up vs any preamp mentioned about including TVC or passives and be able to drive any SS amp with aplomb.

http://www.diyaudio.com/forums/tubes-valves/136935-looking-6aq5-audio-preamp-schematic-2.html

Even the components are listed, so getting a hobbyist to build one for you would be simple, or see if Poinz still makes them (his chassis work is great).

[Ericus Rex]

Build your own!

http://www.audiocircle.com/index.php?topic=111557.msg1154303;topicseen#new