Budget preamp with quality volume control

@clio09 Hi bro, may I seek your advise which one should I get ? Music First pre-amp (used) or Khozmo pre-amp (new) ? Music first 75% expensive than Khozmo in my country. Many thanks!

@tyray Wrote:

Is this tube the VT231 version? Where to buy? The link you left is not working. Thanks

Yes! Call Andy at Vintage Tube services, knowledgeable man. See below:

Mike

https://vintagetubeservices.com/

@ditusa 

I use NOS 6sn7GT Ken-Rad (Pre-Ge) staggered plates with black carbonized glass.

Is this tube the VT231 version? Where to buy? The link you left is not working. Thanks

Give the Audionics BT a try.  A great sounding preamp (voiced like an Audio Research SP-6 ) with a buttery smooth volume control.

I will second the PS Audio Gaincell... I paired it with a Parasound A23+ amplifier and this combo blew me away with a pair of Zu speakers. Also played well with my KLH Model 5's. I have a Denafrips Venus II 12th DAC and find the DAC in the Gaincell to be much better, so much so I am selling the Venus and my Athena preamp. The sound is very dynamic, with a huge soundstage. I normally detest chip DACs, that digital sheen really fatigues the ears. I have had no issues with listening for hours to the Gaincell. And the folks that have heard it are saying the same. 

Audio-GD...Best bang for the buck. Very Musical.

Not maybe what you want to do but have you considered making  your own passive. I have just made one myself using a TKD potentiometer, much better than the often touted Blue Alps. 

The adcom gfp-750 linked earlier listed on usam is mine 

it is a very fine piece 

I have used a freya + but I found it to be not as full sounding as the adcom 

or my van Alstine , audio research or B&k for that matter

Yeap, it is under my radar. Did you find the tube in RP-1 changes the sound signature as compared to SS pre? I often heard the tube (for other preamp) just serves as a buffer and does not change the sound at all. But I hope that is not the case here. Also, have you tried the tube rolling before and does it change the sound?

I had the Rogue RP-1 and found it to be an excellent preamp.  A modest windfall permitted me to trade it towards an RP-7, which I have found to a most excellent preamp.  While not exactly a “budget preamp,” the RP-1 is worthy of consideration, and, as you light out, it has a number of great features.

See if you can find an Ayre K1xemp ( its old but fabulous....)

Music First Audio is a subsidiary of Stevens & Billington which is why their products use those transformers in their design. When S&B used to let people use the transformers for DIY and OEM John Chapman at Bent Audio built a very nice passive preamp with them and when S&B pulled the plug on DIY and OEM he switched to the Slagle autoformers and developed his own module with relays. If you can find one of his preamps used it would be worth trying out.

I have and have had many passive preamps over time that used quality attenuation controls. Everything from a simple pot in the box using NOS Noble potentiometers to Khozmo, Slagle AVC, and S&B TVC passives (all of which I DIYed and all had dual mono attenuation). While all of them performed well for me, the best bang for the buck in my opinion is the one I didn’t DIY which is the Lightspeed Attenuator.

Music First Audio was an early adopter of the transformer volume control, or TVC.  I believe they use S&B transformers.  Transformers use two coils around a core and offer isolation while autotransformers, or autoformers, use only one coil and do not isolate but do apparently have a few advantages when used as volume controls.

Autoformers allow for the same voltage/current transformations that typical transformers are used for and have increased power handling capability, flatter frequency response, lower insertion loss and lower distortion than conventional transformers of similar size and cost.

I do like the Apple remote functionality with the icOn 4PRO.  I also like the large display that is so easy to see across the room.  Functionally, it offers everything I want in a preamp, including an HT pass-through.  I have not tried Music First or any of the other transformer VCs, so cannot make a comparison between autoformers and transformers in my system.

If u have gain issues do not touch the topping pre90. It ONLY worked for me with amps that had gain adjustments, such as the Benchmark AHB2 and the Parasound A21+. It was terrible with about another 5 amps I used it with.

The Sxhitt Freya+ has a lot of features and sounds OK,, but does colour the sound.

The Schitt Sys maybe something that woks for you. It only supports RCA.

You can always bite the bullet and get what I think is an amazing preamp and any price, the Benchmark LA4.

Linear tube audio MZ2. https://www.lineartubeaudio.com/products/mz2mz2-s

Linear tube audio MZ2. Don’t think you can beat the quality for the price: https://www.lineartubeaudio.com/products/mz2mz2-s

I did see the icOn 4PRO in action at an Audio Show - very impressive - and a very easy to use remote because it’s taking advantage of the Apple r/c.

I think that would be my choice if I were to go for anything. Helped further by your endorsement and experience with other passive preamps.

The other popular choice is the Music First - but the icOn has great convenience features in comparison.

+1 @mitch2.  Thanks for the elaboration.

Every passive attenuator company says the same thing, Goldpoint, the LDR folks (i.e., Lightspeed and Tortuga), manufacturers that put attenuators in their DACs like Metrum and Sonnet, and more.  Some say it louder than others.  Hattor/Khozmo offer both options, as well as op-amp or tube active stages to follow their passives, if desired.  I have tried more than a few passives, and currently own 5 different passive units, Goldpoint, Khozmo, Hattor, Endler (attenuators that mount to your amplifiers), and an icOn 4PRO autoformer.  I have also owned the Metrum Adagio DAC, with a lossless volume control.

The ONLY one of those passive solutions that IME preserves the tone and drive to the same level of an active preamp (or active buffer), regardless of how short the ICs are, is the icOn 4PRO AVC preamp, which uses Slagle autoformers.  The autoformers (a type of transformer) have the ability to decrease the output impedance while performing attenuation.  I really like the sound of the 4PRO but I also have a custom, higher quality, Khozmo dual mono passive unit that I use in front of a SMc Audio solid state unity gain buffer, which results in a quite low impedance signal going to my amplifiers.  I like the sound of the Khozmo/SMc buffer combination a little bit better than the icOn 4PRO.  The buffer does not provide gain (above unity), but with the buffer in the path following one of the  passives, I hear improvements in bass, dynamics, tone, and drive, over using any of the passives (except for the icOn) without the buffer.  The icOn 4PRO does not suffer the losses described above that I hear from the other passives.

All that said, only you can decide what type of sound you like, and what you hear in your own room with the equipment you have.  There are many here who like having a passive attenuator, and are happy with the sound.  In the end, any of us here can describe what has worked for us but "try it for yourself" is the only answer that really means anything.

In-line attenutor is just a fixed output passive preamp as opposed to passive preamp with variable levels of attenuation. Not clear what "Indus" is but if Rothwell refers to their in-line attenuator, the output impedance is stated as 3750 ohms, a bit lower than the Schiit SYS (5k) but still high enough to reduce the impedance ratio (approx. 8.6) down below the desired 10. Note that the cable I was using is merely 12 inch long and my Parasound amp has a reasonably high 33k ohm input impedance. It is still likely the company’s in-line attenuator will impact on the sound quality as SYS does. As such, I have no longer considered the passive preamp or in-line attenutor option.

Some active (with gain) preamps also have attenuation function in addition to amplication, such as SPL Volume 2 (-4 dB) and some others. All the Schiit active preamps starts from a "amplication factor" (Schiit refers it as "gain") of 1 which gives no volume (dB) increase/decrease. The formula is 20*log(amplication factor). So amp. factor of 1 give 0 dB. When the amplication factor is less than 1, say, 0.63, change in volume is 20 log(0.63) = -4 dB (like SPL Volume 2 mentioned above) indicating that the preamp is actually performing attenuation. Those active preamps with gain is exactly what I am shooting for.

Thanks - this company thinks otherwise due to how short the cables for interconnects are etc ... read here:

http://www.rothwellaudioproducts.co.uk/html/the_truth_about_passive_pre-am.html

@chopandchange 

if I am only using the ONE digital source - would I really need a pre-amp at all?

That has been a question asked by many over the years.  Having enough voltage is one piece of the puzzle but impedance compatibility to drive the cables and power amplifier is another piece that is not addressed by simply putting an attenuator in the signal chain.   In short, many have found that preamps having a high'ish impedance input and low'ish impedance output to the power amplifiers seem to do a better job of preserving tonal qualities, dynamics, and drive, compared to using an attenuator alone.  A unity gain buffer following the attenuator can do the job fine in cases like yours where there is enough voltage coming out of the source.   

I was looking through this post and thought - if I am only using the ONE digital source - would I really need a pre-amp at all? After all, a preamp deals with the switching of inputs (and I only have the one input) and also gain control but there's enough gain on a digital device anyway (broadly speaking).

I would need an attenuator - not a pre-amp (if you can distinguish the two) - so perhaps a high quality passive will do for me with no selector knob and only attenuator control. However, I would still need this single pot to be of high quality too - anyone know of something?

Ideally I would like a r/c attenuator if that's possible.

The classic Adcom gfp 750 and Apt Holman recapped can still be found at a affordable price but Ayre k1x or Threshold Fet 10e would cost over $2k.  They must be the crown jewels top of the line back then.  Thanks for the recommendations.

I would agree with above find an older badboy. It will mop the floor with a new cheap  one. I would personally  look for an Ayre k1xe  or k3 or a canary 800 pair. The old classe Dr series would be great a threshold  fet 10e etc get yourself  a top pf the line older unit.

You want a good preamp? Find yourself an Apt Holman that's been recapped. Has the stepped precise volume control you want. Yes, it's 40 years old but there are few better "budget" preamps on earth.

Late to the party; Schiit Freya+ here as well. Initial money saved on a comparable pre will get you into upgraded dac, (if wanted) ect. Season with NOS tubes of your choice whenever upgraditis hits; as opposed to spending 4K on a newer,"better" pre.

Yes, $700 is fair used. You would probably just have to update the firmware through a USB download. Make sure the seller has the original box, packing materials and manual so if you wanted to sell it at a later date.

With mine I don't intend to keep it as Wyred 4 Sound let's you trade in or should I say trade up when bought directly from them. I agree with you that the dac is the weakest link, but it's built like a tank with shielding and other positives and at the time I just needed a reliable head unit on the cheap and usually in those circumstances the dac is what it is.

Even though I have thousands of cd's and hundreds of 'albums', as I said in an earlier post I am a crate digging needle dropper and I mostly use my turntable and can always upgrade and invest in a separate dac at a later date since I already own a cd transport. And that's exactly why Wyred 4 Sound made the mPRE the way it is cause it is essentially a head unit/pre amp 'starter kit'.

I actually enjoy to read about the hardship that Steve Huffman went through when he heard the transformer buzz/hum from his over $10k Luxman and then found the Puritan 156 to finally tame it down. My Parasound amps have a bit transformer hum as well that I need to 2 ft close to hear it but is enough to trigger my irritation.  I was doing the similar things, i.e., DC offset and Monster power conditioner, trying to get rid of it but without success. It is tempting but I could not justify spending $2k to cure the hum of $1k amp.

I found a used mPre selling for $700.  Is it a fair price? It is such a pity that its DAC section only supports up to 24/96 (usb) and 24/192 and no DSD. Well, let me sleep on it.  

That’s supposed to be outstanding synergy not ’outstanding symmetry’. ’Duh’.

One night while glancing through the Wyred4Sound website, the proverbial "Duh" hit me like a hammer. Why not the mPre?

This is exactly what happened to me. I first wanted the Wyred 4 Sound STP-SE Stage 2 preamp. I didn’t even know the mPRE existed until about 2 years after trying to save up money for a used or new Wyred 4 Sound STP-SE Stage 2!

Funny you should ask about the dac even though my main way of playing music is old school needle dropping! Not streaming nor playing cd’s, I still wanted an inexpensive transport of the best quality sound and (low) price ratio I could find, I narrowed it down to the Audiolab 6000CDT transport. Do you see a recurring theme here? Keep in mind I have not run/burned in the dac as of yet but I do know it responds to what you have going into it. So the better quality of interconnects and transport it responds well to.

Sound stage, width, depth and holographics are there as well. It’s as if this little mighty mite is responding to the gear you connect it up to just like a higher priced preamp would.

The toslink connection to some may sound overly warm but I have separate Power Sound Audio (PSA) subwoofers and I can turn down the gain on them. But my cd transport connector of choice is the 聖HIJIRI Million HDG - RCA Digital cable. Again, what I’ve found is the mPRE does respond to what you put into it.

I think I’ve been lucky with selecting components with outstanding symmetry but I’ve also ’paid the upgrade price’ over the years for it too.

There’s one little thing I need to share with you here. I did splurge a bit on my most recent acquisition and that was a Puritan 156 power conditioner and after hooking everything up to it - Wow! I’m hearing things I didn’t even know were on the cd/record/vinyl! As we say here on audiogon, ’I hope this helps.’

@tyray Thank you.  I also like what I see from this review. How do you like its DAC?  In particular, how are the soundstage width and depth?

https://positive-feedback.com/Issue72/wyred_mpre.htm

@zlone is correct. The reasons, as shown in the "measurement" section, are (for Freya)

The active balanced output impedance was the same with or without the tube stage operating. It was close to 810 ohms at 1kHz and 20kHz but increased to 6900 ohms at 20Hz. The buffered unbalanced output impedance at 1kHz and 20kHz was inconsequentially higher than the specified 75 ohms, at 90 ohms. However, it rose to 3100 ohms at the bottom of the audioband. With the tube stage operating, the unbalanced output impedance was 3267 ohms at 20Hz and 1200 ohms at 1kHz and 20kHz.

Especially on the low ends from either output, the output impedances are much higher than the specified 75 ohm.  Frequency dependent impedance, interesting, needs to be watched for.  Lean something each day.  Thank you.

In short, I am looking for a budgetary preamp with quality volume control that either has relay switch stepped control or precise potentiometer for left-right channel match to curb the issue.

@lanx0003, The Wyred 4 Sound mPRE preamp priced at $1100 has both active and passive topology. The volume control is a switched resistor array (based on the $2000 Wyred 4 Sound STP-SE preamp) and it paired with my Clayton Audio M200 stereo amplifier, a full loom of 聖 Hijiri Nagomi interconnects the synergy is there in spades and my modest rig sings. At it’s $1100 price point it also comes with a remote.

Check it out: https://wyred4sound.com/products/mpre Here's a review from sixmoons.com:https://www.6moons.com/audioreviews/wyred8/1.html that will more completely explain the specs of the Wyred 4 Sound mPRE preamp.

@jpasko01 Two things regarding the impedance matching with the Freya, if you are using unbalanced, you are fine, however output impedance is 600 ohms for balanced. More importantly, read John Atkinson’s analysis in the Stereophile review. Again, regarding balanced connections, but he suggests anything under 10Kohm input impedance may not do well with the Freya. My amp is right at 10K, and seems fine. 

As many of you know, the basic relationship between the signal transfer (in terms of voltage) ratio to impedance between output (source) and input (load) is

Vi / Vo = Ri / (Ri+Ro+cable impedance), where V = voltage and R = impdenace

For a standard 75 ohms interconnect cable, without loss of generality, if your preamp output imp. is roughly comparable to the cable impedance, Vi / Vo = Ri / (Ri+2Ro). As a rule of thumb, it is desirable to have Ri is at least 10 times higher than Ro. The corresponding Vi / Vo = 83%. There will be 17% signal loss, acceptable (see below for the coveat) but not ideal. If Ri is 100 times Ro, the Vi / Vo ratio will be 98%, only 2% signal loss and will be deemed ideal.

In @jpasko01 case, i.e., Freya -> Bryston 4B3, Ri = 100 Ro and therefore the signal loss is only 2%. The pariing should work like charm. In the case of a passive preamp SYS (Ro = 5000 ohms) into my Parasound A23 (Ri = 33k ohms) where the ratio is merely 6.6, the Vi / Vo = 33000 / (33000+5000+75) = 87%. This 13% signal loss is significant enough to cause noticeable sound degradation that I heard. This demonstrates that the ratio of 10 is just a rule of thumb, the ratio should be as high as possible like 100 to be ideal. Since I have not seen a passive preamp impedance is lower than 5k ohms, practically only the active preamp is possible to achieve an ideal impedance match.

Zlone, interested in your comment above.  
I have a Bryston 4B3 (7.5kohm input impedance). The Schiit Freya + has been mentioned several times on this forum as a decent low cost match.  
Freya + has a 75 ohm output impedance.  Not sure why this wouldn’t work?

@pwayland I could not find that gain stage info in the manual for my Parasound amp. The control on the back are the unity gain control whose function, as you know, is to throw away some of the preamp output to get the main volume control in the region one likes best (gain staging process). I am not sure if I could simply get rid of it but I could max it out so there won’t be any variable resistor in the signal path. Then I could use Active preamp without gain in lieu of with gain (like you said) to adjust the volume. At the mean time, I could also bypass the digital attenuator in DAC by switch the volume to the "fixed" mode to avoid sound degradation. By reading the specs, the SPL Volume 2 as you have suggested or several Schiit products such as Freya, Asgard 3, Jot 2, or Magnius on my list will serve that purpose in addition to impedance matching. These Schiit products also come with active w/ gain so is handy when needed. Thank you that really helps me to eliminate a few other choices.

Btw, while reading the tech info. (as shown below) in SPL Volume 2 manual, it really explains what I have experienced with the SYS... It is actually a much better passive preamp compared to the cheap in-line attenutor I purchased for the sub. I therefore decide to retain SYS for my sub. instead.  

Active or Passive?

It is claimed that passive circuits are less signal influencing and more puristic and therefore better. Well, that is not so.

A passive control element such as a potentiometer in the signal path, which is not electronically buffered, influences the frequency response and phase position. Both change continuously as you change the volume.

This is exactly what does not happen with an active control.

secretguy

1,397 posts

06-28-2023 at 10:34am

Like any of you could hear the difference in volume controls

Showing how much you know…….again.

The volume control used in a preamp is more important than the topology.

@lanx0003 One thing to consider is the gain stage of your power amp. My pass labs power amp has a gain of 28db and therefore only really requires a buffer preamp. It would be worth looking at the gain of your power amp and use the appropriate preamp. It seems your dac  has a gain stage on the output and  between that the gain of your amp, you have too much gain. One solution is to replace the potentiometer (s) on your power amp with one with higher resistance. To me, it doesn't make any sense to add yet another gain stage and volume control in front of your amp that has a potentiometer in the signal path. Another solution would remove the potentiometer from the amp and get a SPL Volume 2 which is basically buffered analog Alps RK-27 potentiometer. 

As mentioned earlier, after trying out Schiit SYS, I no longer consider passive preamp. I suspect the degraded SQ, i.e., soften lows and restrainted less airy highs, is resulted from the mismatched impedance. In addition, the headroom becomes fairly limited because of signal loss. Most of passive preamps have pretty high output impedance and unavoidably create mismatch issues with my amp (20k ohms - 33k ohms). I could not locate the specs for Pacette passive linestage even on their website but suspect its output imp. is no exception. But thank you for the thoughts.

https://www.audiogon.com/listings/lisb538h-placette-audio-passive-linestage-solid-state

@audphile1  I have looked that option earlier.  Since I have hard time to pay $1000 for 1st Watt B1 buffer preamp, the only option I have looked is the Zerozone Pass X1-B Buffer Preamp from Aliexpress for around $230 incl. shipping.  But unfortunately, ZZ pass x1-B only works with Pass amp. If you know other source pls let me know.

@zlone My amps should be fine with Freya.  Two are 33k and one 20k. Thx

Given the impedance mismatch with the passive preamp, it might be good to know what power amp you are using and the input impedance. The Freya requires at least 10 Kohm to work well. 

One other option for you is this classic Nelson Pass design. 

The passive preamp Schiit SYS is first thing I tried. Although many people have attested it is a good sounding preamp, I found the low end notes thru it are softened. High end notes are restrained and less airy. On the paper, the SYS’s output impedance is as high as 5k ohms so the ratio of load impedance to its output does not reach the desired 10. It has impedance mismatch issue. I am not thrilled by it and that is the reason I am only looking at the active preamp with gain.

Neverthless, I will keep looking into Khozmo preamp while its spec. seems not available even on its own site. Thank you for the recommendation.

If you are satisfied with the output from your DAC, just need to be able to reduce it, then a passive preamp might be the ticker.

I'm using a Khozmo Acoustic preamp, 3 inputs, an outstanding volume control (i'm using the shut+z-foil), extremely transparent. The remote controls power on/off and volume only, the input must be changed manually (which is not a big deal to me...).

I use the PS Audio Gain Cell preamp, have for about 3 years.  My system is quite resolving and I can attest that even at low, and sometimes very low volumes I don't seem to lose a thing.  No bass loss, no high end loss, all is still there.  The DAC is quite good also.  You can find them used from time to time at "The Music Room" website and you have a trial period if you don't like it.  They are very good to work with.

Used Peachtree preamps with built in Sabre DAC as well for around ~$500.