I'm considering replacing my passive preamp with a tubes. Is it worth it?

I would like to know if it would be worth it to trade my passive preamp for tube.  Would the change make a significant improvement?  

My setup:

Magnepan MG .7
Mod Squad Line Drive passive preamp
Bryston 4b-st amp
Rythmik f12 sub
Bluesound Node
Tidal streaming

My budget on a preamp would be $1k.  If the answer is "yes" then opinions would be welcomed.


The answer is "maybe". Some will tell you "yes", some will tell you "no".
Since it's your money, the only opinion that really matters is your own.

So you should just look for a tube preamp on the used market that is a good deal and try it yourself. If it works, great. It it doesn't work out, sell it, and go back to the passive. At least then you will know for yourself.
I totally agree with jmcgrogan2 it depends but I see some pretty cool tubed preamps for sale here in your price range.



No affiliation with any sellers those both look like good deals and good preamps, good luck and happy listening!

What would I expect to be different with the tube preamp?

The opinions are appreciated so thanks
amritash I’m considering replacing my passive preamp with a tubes. Is it worth it?

Schiit Freya at $699 with trial period, it has 3 different modes, low gain tube, low gain discrete solid state, and unity gain passive, balanced or single ended and with remote control.
And with the Bryston 4b-s input sensitivity being only 1.4v input for full output, you don’t want any higher gain or the volume control will be down very low for loud listening, and you’ll have very little range on the volume control..

Can’t go wrong with this choice best of all worlds, specially seeing it’s designed by Mike Moffat who was head designer at Theta.

Cheers George
The two preamps listed on Audiogon are highly rated for sonics and build quality.
But the Schiit is getting raves for its price and performance. Plus, you could run it balanced to your Bryston.
An active tube preamp would add timbre and texture to the sonics of your system, since each brand of tube offers a sonic signature. It may give you more flexibility on fine tuning the volume control since it has an active gain stage.

It is most important that the output impedance of the preamp be a good match for the amp. The amp’s input impedance needs to be 10-20X greater than the preamp’s output. That would allow for transients in the lowest and highest frequencies.

t is most important that the output impedance of the preamp be a good match for the amp. 
Tested Stereophile: "Bryston measured just over 33k ohms at the balanced inputs, just over 47k ohms at the unbalanced."
This is a match for any preamp, passive or active so long as they have little or no gain as the Bryston 4b only needs 1.4v for full output, and most sources have over 2v already.

Cheers George

 @amritash what do you feel is missing from the sound coming out of your setup?

I appreciate everyone’s thoughtful feedback. Thiefoflight that is a spot-on question. I had a weird problem happen. I was having trouble with the volume going high enough and it sounded muted  The source of it turned out to be the iPhone from which I was streaming the Tidal to the Bluesound Node. I found out that my sound improved enormously when I replaced the iPhone 6 plus with a 7 plus.on the old phone. Not fathoming it could be the source I assumed it was the passive not providing enough gain. I just so happened to discover this because I smashed the iPhone 6 and needed to get a new one. This had been going on for weeks and just replaced the phone two days ago.

 I never would have thought about getting one had the problem with the phone never occurred. It sounds awesome again now. But since I got the bug in my head about the potential to get it even better I’m still pondering the value of adding the tube preamp.

@amritash Interesting. Were you streaming (selecting your Node as output) from Tidal, or using the headphone jack from the iPhone as an input to the Bluesound? Considering that the stream should only be data and the Bluesound was converting to digital and amplifying, then I don't know how the quality should have been different from the 6 to the 7. If you were doing this with a bluetooth adapter for Bluesound, then it would be a much different story as iPhone doesn't support aptX, so that means that it is getting processed by the iPhone's DAC and voltage before streaming out, and that would be why the iPhone 6 sounds so much more inferior to the iPhone 7.

Outside of the gain issue, I think more detail on where you think your sound can improve overall (do you feel that specific tones are missing or too shrill? bass too sluggish? etc) would help understand whether an active preamp would help.

I'm a big fan of tubes, but it's also a pandora's box... one that has allowed me to really fine tune my sound, but also spin my head in circles at unnecessary times.

Anyone else make a preamp that is switchable between tubes and SS stage?  They Freya looks good but I need at least 5 (6?) RCA inputs and I want it in black without the clicking volume control.

Thanks everyone...
Get a old CJ tube preamp this would sound musical with a lush tube sound,Enjoy.

without the clicking volume control.
It’s not a "clicking" feel, it’s a smooth rotation, but it does activate different relays inside to give 128 levels via a micro processor. Relays are far better than any normal volume control, as they have far better contact pressure than a resistive track with a very light wiper contact that normal volume controls have.

" Freya uses a sophisticated microprocessor-controlled relay-stepped attenuator for perfect channel matching and zero distortion—and with 128 steps for ultra-precise level control "

Cheers George
That Brown Labs sounds as though it's an excellent buy.  It looks great too.  I am leaning way over to it right now.  
Try a Bryston bp 20 , 25 or sp2 . One of the sweetest volume controls around . Oughta work well with your amp .

I did just that, switch from a passive to a tube pre. I was using a DIY built copy of one of the best current Passives, the Music First Audio Baby Reference. It was truly excellent, neutral, transparent, detailed, but. I felt I was missing some dynamics and changed to a Modwright 36.5 and yes, dynamics were clearly better and the sound was richer. The textures and notes seemed fuller, less dry.

 So in my case, I definitely preferred the tubed Pre. The Modwright would be above your price range, maybe not the L100. I agree with EBM, if I was looking for a $1000 tubed pre, you couldn't  go wrong with CJ. I used the LS17, I think it was, for a few years, a wonderful unit.

Music First Audio Baby Reference. It was truly excellent, neutral, transparent, detailed, but. I felt I was missing some dynamics 

Being a passive and seeing what that source signal had to go through, I can understand why it was missing dynamics. That amount of wire and even more in the more in the transformers, would be like putting the dynamics through a funnel.


Cheers George
Personally, I've never had any luck with passives....they work in my system but not well.

Some thoughts....

There is a big controversy between passive vs active preamp. My thoughts are based on what kind of source you have. If you have a DAC with a nice tube or Class-A output stage, it could be that a passive preamp may be your best choice. It really depends on how the DAC I/V and audio stage translates those DAC pulses into waveforms.

Since you have a Bluesound as your DAC (or iPhone), putting in an active preamp can really help translate more body and mid-bass/bass frequencies. In a sense, it can give the waveforms a lot more muscle.

Unless you’re actually looking for more of the colored tubey/bloomey sound, I would look more towards the stronger/clearer sounding tube preamps. Or look at a nice solid-state Class A preamp. I cannot advise on tube preamps (not my area of expertise), but some solid state amps include the Krell KAV-280p (can be found close to $1k sometimes). The Krell KAV-280p is the oldest Krell I would recommend, but it’s excellent.

There’s a PS Audio PCA-2 up for sale on audiogon. It looks nice with a hefty power supply.

My experience with Bryston preamps (BP-20, SP2) is that they are very clean/clear with lots of attack, but no decay. If you’re looking to get a lot of midrange or mid-bass body, Bryston is somewhat weak in this area (in my opinion).  It’s just not as strong as the Krell is.

It could be challenging to find a good Class A preamp around $1k, but you can do it if you look.

Class A preamp
All active preamps are Class A, I don't know of one that's Class A/B or B.

Cheers George


Are you absolutely sure about that?  If you're talking about tube preamp, I could probably see that as being true because of the nature of how tubes work.  However, solid-state preamps do not necessarily have to be biased into Class A mode.  It's a specific circuit design that does this.  This is true for both monolithic op amps and fully discrete analog circuits.  I have found that if the manufacturer has not specifically stated that their device is Class A, I will assume it's Class AB.

Almost 100%. from what I’ve seen none have left Class A and gone into A/B, I think a manufacturer would be mad to do that with a preamp, do you know one that does?

Cheers George
I bought myself an Audible Illusions Modulus 2D yesterday.  It popped up priced under 500 and I leapt on it.   I am very excited.  It should be here next by early next week.
I have used Audible Illusions L1 tube pre-amp very nice. 
Do a google galen carol (out of TX) he sometimes has refurbished AI under $1K. 
... I just recently upgraded into a new-to-me Rogue Ninety-Nine and Bryston 4B-ST, and am very happy with the results coming out of my Gershman Avant Garde RX-20 speakers...
One of the finest designers and manufacturers of pre amps, Mr. Emmanual Go of First Sound, started by making passives and now produces only actives.   

That is in itself is a statement given the superb quality of his products.  Vacuum tube pre amps at their zenith.  
I just auditioned the .7 with a NAD C 368 and the Rogue Sphinx -- so two Class D power amplifiers, but SS pre on the NAD and tube pre on the Rogue. On those two, it was a pretty marked difference in treble and how forward the sound felt, with noticeable brightness with the NAD. We were listening to a Wynton Marsalis CD, and it was like his mute popped halfway out of his horn on the NAD compared to the Rogue. And I'm honestly not sure which I prefer, but it's certainly different.
If you can be patient and are willing to consider vintage, you may want to consider a Harman Kardon Citation I - perhaps the best tube amp of all time.  I purchased one that was reconditioned for about $1,000.  It has one of the finest phono stages too.  My only caveat is that if you have very sensitive speakers (95db+), the HK can be a little noisy (hiss) at low volumes.  

I currently am using an Audio Research LS27 tube preamp.  After close to 50 years as an audiophile, I have found that a true quality tube preamplifer is the single most important part of a high end audio system itself.  I have previously had an Ayre K1xe and presently am usng a Rega Orisis  integrated, but neither can come close to my LS27.  It seems that what goes into my Audio Research LS27, what come out sounds even better.  It's that simple.   Just one person's opinion.
The thing about a tube preamp is that the preamp is just the start of things. IME, you begin with which tubes to go with. I prefer the 12AX tubes. I have an LS15 preamp with modifications to the SS DC section, soft recovery diodes, better caps, as well as bypassing the caps in the audio section with Mundorf Silver Golds. Despite all the enhancements that made, it was still less than I wanted. Then I saw a little Chinese made 12AX7 based preamp at a place that sells things that Amazon either couldn’t or chose not to sell. It’s 12AX7s were broken, and some plastic covers off the rear pillars were missing, but it was perfect for me. It had a tube rectifier so I didn’t have to quiet the DC down to keep noise out of the low level details. In fact, other than rolling tubes, the only thing that I did to it was to bypass the large output coupling caps with Vcaps. Put in some Telefunkens and put a fork in it, you’re done. Not very versatile, but if you want tube flavor, it’s the way to go. My AR and Coda preamps are sitting idle. I should and likely will try some copper Vcaps in both preamps, but I think 12AX7s just have a bit more magic if you will, than 6DJ8’S do. So, 270 for the preamp 130+/- for caps, and tubes for what you can find them for, my source has Telefunkens pulled from test equipment, they test new and seem to last. YMMV

This is the preamp I now use;

I've actually gone from a tube pre to a passive. I used to own an Octave Audio Phonomodule. At the time, i thought it sounded good. That was until my mate brought his Dave Slagle autoformer TVC over. The difference was day and night. Soon after i built my own and have never looked back. I will never go active again. 
But as they say, it's all system dependant. 

A used  Rogue Metis preamp should be in your price range. For the price a nice tube pre with easy tube rolling. Have been using one for a year now and I'm very pleased with it.
Congratulations on your new acquisition. Enjoy it.

Out of curiosity - what was your passive preamp?
Alternatively you could have purchased a Bluetooth DAC which has a healthy 2V out and kept your passive, if you like it's sound. You still should get a Bluetooth DAC, rather than connecting the iphone directly to the preamp.


So Ive received an have listened to the Audible Illusions modulus 2d.I am in love. I put inReflector 6H23p-EB / 6922There is absolutely no comparison between the Mod Squad Line Drive passive. The AI sound is just so beautiful. I think that I’ve finally heard the audiophile sound. I could listen to this and do for hours on end.
Now that I have been bitten I’m curious what I can do with an upgrade on it. The small thing that I would like hear is an improvement is the highs being a little more distinct. Imaging on the AI is great but I know there is better. Im considering some but I’ll post the question in a separate thread.

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I have a Bent Audio AVC passive and a VAC Phi Beta tube preamp in my rack, along with a high input gain tube amp (VAC) and SS amp (Plinius). The Bent sounds great with both amps but I always go back to the tube preamp for the bigger, more solid sound stage it throws, and the improved low-mids.

That being said, I have heard a Music First Baby Reference passive in this system and that was truly special. It lacked for nothing. Great piece of gear.
From Audible Illusions... If you have not already made a decision, you might want to try a used AI Modulus 3 or 3A. It is a perfect match for that Bryston and the Maggies.

The Music First is a TVC and is not really a passive.
Can you please let me know what you "lost" in sound, when you introduced the Music First in your system, compared to the VAC Phi Beta? How would you compare the Music First Vs Bent Audio AVC?

Sorry for the delay in responding. I just noticed your post. First, I've never owned a Music First, only listened to a friend's in my system. I did not mean to imply that anything was lost in moving from the MF to the Vac. Rather, as I recall, the MF was more similar to the Vac than I expected, and different from the Bent in the same ways the Vac is, as I described above.