tube preamp in SS receiver loop

From noob, a very basic and probably very stupid question that I can't seem to find answered elsewhere:

I want to experiment with inexpensive tube sound to augment a modest solid state receiver. I have looked at tube buffers marketed expressly for that purpose, that is, for those who want to insert tube "warmth," which I know is a kind of distortion that many hate, into solid state setups (e.g., the Grant Fidelity B-283). But I would like a tube phono stage as well. So I am looking at a tube preamp with one line level input and one RIAA input. But I would like to use it on all the line level sources coming through the receiver (tuner, CD, computer, ipod, whatever), so it would go between the pre out and main in on the receiver, or else in the tape loop. In other words, the line level signal would go through the SS preamp, then the tubed one (the turntable would of course go straight into the tube preamp). Is it kosher to use a preamp in this way? That is, as a buffer stage that comes after the solid state receiver's preamp circuit? In other words, can you use a variable gain preamp as a (passive?) buffer? Clearly I have no idea what I'm talking about. Thanks for any thoughts you may have.
The answer is yes you can but I would place a multi-source tube preamp (w/ phono) between the sources and the receiver. Wire all 2-channel sources into the tube preamp directly and then run a set of interconnects between the preamp output on the preamp and a single input (not phono) on the receiver. You'll have two volume controls but you can set the preamp's volume at a fixed point and attenuate with the receiver's volume.

If you have a Home Theater receiver then you would continue to run video & multichannel sources directly to the receiver and not through the tube preamp.

Another simple option would be to just add a tube amplifier and preamp out of receiver for the main two channels.

Feel free to call me if you have any questions.

Well you can put a tube buffer device in the tape loop to get some tube effect. That is a good place because you can easily hear the difference in an A/B comparison of its effect on any particular recording/source. It would be my preferred location.

You can also get a seperate tube phono stage and just plug it into one of the AUX imputs of your reciever, but before doing so you will be able to hear the recievers phono stage (if it has one) sound with the tube buffer you put in the tape loop. Seperate tube phono stages can be difficult and expensive. One would not be my first choice unless it were going to be a major source.

Thanks very much for those insightful responses. I agree, Newbee, that the tape loop would make sense if I do go the tube buffer route. Thus I probably should not opt for the multi-source tube preamp but a tube buffer instead, maybe with a separate pbono stage.

Burt, I probably should have mentioned that I am using a 70s era Marantz receiver, not home theater. But I have been mistakenly believing that I couldn't wire multiple sources to the tube preamp's single line level input because of the hum and signal degradation that would be introduced by several sources at the PHONO input. But at the LINE stage input, I now realize, I could indeed wire different sources directly to the preamp's single input using Y adapters or other multi input wiring.

So the decision becomes whether to use a buffer and perhaps a phono stage, or a preamp with all the sources wired directly into it. I guess I wanted to be able to continue selecting the source on the receiver. But that doesn't matter that much.

This is all very helpful in my thinking, so thanks again for your wise counsel.

If I have it right, you're talking about connecting several sources into one input on a tube buffer using Y-adapters. In that case, it's your original idea, that this may cause hum and noise problems, that I think is correct. Using Y-adapters is ok if you're feeding out from a component, but never if you're feeding into one. Hum and noise (d.c. overload) is predictably the result. If you need to handle several sources with a tube buffer, one way might be to insert a multi-source capable input selector box between the tube buffer and the sources and then feed the buffer into a single receiver input. But, OTOH, if you end up having to go the tube preamp route, then most certainly you should connect the preamp directly to your receiver's main in - this allows you to bypass the receiver's preamp section altogether, and with it, the receiver's volume control (pots of older design, or on relatively newer, but cheaper, gear are often sources of distorions and coloration in their own right). So if your preamp has a decent volume control, it may be an upgrade in that regard too, as well as the opportunity to introduce tubes. In any case, as long as you can avoid it anyway, it's not really a good idea to double up on volume controls as long as the idea is to build a revealing system. Hope this helps. Regards.
Sorry Vesuvio, I see now where your preamp would only have one line input in addition to the phono input - didn't pick up on that the first time around. But my advice is still essentially the same as for the buffer - you'd still end up needing a selector switching box for the all the line sources, again, as Y-adapters just wouldn't work in either case here. A selector box may be ok with you or possibly you may just prefer to bite the bullet and find a linestage-with-phono preamp that can handle the number of sources you need. Post again if you want, if I still don't have it right.
I would avoid the Y adapters if possible. Ivan is correct but then, again, we're back at the multi-input tube preamp vs. a tube buffer PLUS a multi-input selector box.

My advice is to try and simplify the signal path as much as possible. Now that I know this is just for 2-channel audio - the preamp makes additional sense because it positions you to eventually replace the receiver for a dedicated 2 channel SS or tube amplifier.
Thanks, Ivan. You have it right. I have a typical vintage solid state midfi receiver with phono, tape, tuner, aux inputs. I started looking into this controversial buffer business, which led me to a reasonable and fairly popular tube preamp, with the phono stage as well, the Yaqin 12B, which I thought might make a good buffer.

But then I wondered if it would work in the tape or pre-out, main-in loop as a tube preamp in series with the solid state preamp in the receiver. Maybe a little redundant, and, as you say, there is the problem with the two volume controls. I don't want to completely bypass the receiver's preamp because I need its tone controls.

So I'm leaning toward the single-tube Yaqin buffer (cd1), and maybe later a phono stage. And one day, maybe either a more expensive preamp with multiple inputs or a complete tube setup. Part of the fun of all this is the journey.

Much appreciate your thoughtful comments.

Thanks, Seattlehifi. I see what you're saying about the preamp over a buffer. Clearly I have a lot of factors to consider.

I'm still leaning toward the buffer for now, maybe the yaqin cd3 (of course, the whole cd1,2 or 3 issue is another big debate in itself! my eyes are blurry from skimming boards). It would fit better in my space and be more of a small mod to my existing Marantz, which I already like quite a lot.

But if I find I really like the tube sound, then eventually I could splurge on an honest-to-goodness tube preamp. Or even integrated. Vintage, maybe. The last time I saw a tube was about 1965 in the back of my parents' monaural Magnavox, which I can still recall sounding awesome. Meanwhile I could ease into rolling tubes in the buffer.
If you go with the buffer don't forget to expirement with using it plugged straight into the main ins on your Marantz - even if you bought it with the full intent of using it as you describe above. The difference in sound quality just may surprise you...or not, but it would be worth it just try it out long enough to see for yourself. But, I believe you're on the right track and good luck with it all, either way.
Thanks. That was my intention, to plug it into the receiver's main ins, with the preamp outs feeding into it. But it will be fun to try different configurations. Unless it sounds awful. In which case it won't be all THAT much fun.
This is very simple. Your Marantz has a mediocre preamp--at best. Furthermore, the tape ins and outs are buffered and will swamp the advantage of an additional tube buffer to a significant degree. They guy that said keep it simple is correct. Buy a decent used tube preamp. Plug your sources into it. Hook its outputs to the main in on the receiver. You're done. One volume control and less gain stages than all the other schemes.
By the way, a tube component that's "warm" is either defective, needs to be retubed or you're comparing it to a real piece of garbage--be it solid state or tube (either architecture can sound like crap no matter what anyone tells you). Tubes are revered for their transparency, liquidity, detail and so on. The idea that they are warmer is a misconception. They're either natural or they're colored ( or veiled, or muddy and on and on).
You have two problems: one is $. The other is you must listen to the actual unit youre buying. I've repped dozens of high-end lines--still do. I saw a mint Golden Tube SE40 rep sample that had almost no time it it. Unfortunately, it had no life to the sound--dull and lifeless. Real music is dynamic and exciting. The unit sat in the rep's closet unused at least 15 years. It probably needed re-capping since tubes hold up well if unused.
Call Andy at Saturday Audio in Chicago and Holm Audio in Woodridge, IL. Both have used tube preamps. Try to get return privileges. Tell 'em Frank Malitz sent you and tell them what you're trying to accomplish. By the way, any good separate preamp--solid state or tube--will outperform your receiver's preamp section. When I was at Onkyo, we could only make decent preamps--never really good ones. We simply didn't know how; a good phono stage is very difficult to design. The line stage is easier and the power amp, easiest if all. I'm generalizing but for mundane Japanese brands (which I also rep), high performance separates are not their strength.
Best of luck.
Other than using a tubed based source phono pre amp or CD player you have a beter chance of problems than improvement. I am not saying you will fail but the source will add great tube sound with almost no chance of failure. You might find a dealer or friend whith something to try or if you buy something and don't like it you can sell it on Audiogon. I build tube gear and upgrade anything, Improve the power supply is all I would do to a reciever. That improves anything.
You are on the right track and I agree with Fmalitz. I have direct experience with what you want to do. When I wanted to do separates years ago I could not afford a tube pre and power amp. Plus I have a fairly large room and I like orchestra and organ recordings, played at a decent level. That cut out the tube power amp, unless I could afford a Wotan or other model for 20K!

I had a Pioneer surround receiver and I was ready to spend money on a tube pre. I bought an Audible Illusions Model 3 (I have since upgraded it to the 3A), plugged it into the main on the receiver and used the pre for switching inputs and volume, etc. I remember bringing my receiver to the High End store and switching between the receiver volume section and the AI Pre. I could not believe the difference, it was amazing. There are a lot of used tube Pre's out there. Also new ones too.
I seem to agree with some of the principles here, but not many of the recommendations. Keeping the signal simple is a good one. Ditching the mid-fi receiver is another (sorry).
Aside from a vinyl record player, most input devices, even quite ancient ones e.g. cassette, reel to reel output at "line level" of around 1v and have fairly standard output impedance (a bit brave, but bear with me). Some newer inputs e.g. DVD, BD, DAB may substantially exceed this (often up to 2v). Consider what a pre-amp "does". Given decent inputs, all a pre-amp really does is to switch from one input to another and adjust the volume (downwards) from line level (or whatever the input level is). So all you need is an input switch and a volume control, neither of which involves tubes at all. It is partly audio "philosophy" but IMHO, at best a pre-amp should be passive and should interfere as little as possible with the sound. So, you can get high quality input switching modules from China with gold-plated relay contacts for $25 (e-Bay). You can spend $700 on a Stephens&Billington transformer-based volume control or $500 on a fixed resistor stepped volume control, both of which are excellent solutions, however, on a budget, the best value for money solution I know is a motorised ALPS Blue-velvet volume control from Germany for $35. You can then get a remote control board and transmitter to switch the inputs and control the volume via the motor from your armchair for another $20 (e-Bay). This leaves 2½ issues: Phono stage - get a cheap solid state stand-alone one for $30 e.g. . You can spend $000's on a phono stage, but we are just experimenting here, right? Second issue, tone control: Tone control should only be used to correct deficiencies in input quality. It is not required for phono, any digital input like CD or FM radio. It can be useful with poor cassette tapes or reel to reel tapes which have deteriorated over time and repeated playback. Again here, what adjusts tone is essentially inductance, capacitance and resistance (LCR) networks - no tubes. These are pretty simple, but if you don't feel comfortable making them, you can probably get a cheap solid state or passive unit. Plug it in between your deficient input and the switching unit. This yanks the budget up a bit, but Musical Fidelity offer a stand-alone tube-based tone control unit called an X-Tone. You can get one of these (the Mark 2 version) for around $200 on e-Bay. Last issue - impedance-matching: All this takes is two resistors per device before the input switch - again no tubes - and I would venture to guess you won't need to do it anyway.
So we have elimiated a lot of noise and distortion (and tubes) from the pre-amp zone. If you still want tubes (I use them), you could get a tube-based power amp. You can get an entry-level built module from China (e-Bay) for $45 or a more professional finished version in a case for $200. You can probably find some worthwhile tweaks and mods on the internet if you want to upgrade this to sound better.
I have a Linn, Majik DSM which is an excellent digital music player, (integrated), with all components connected to use it's volume and switching, (and great DAC), and then fed via pre-out to a MasterSound 300BPSE which is also an excellent, Italian integrated which I am only using the Line-in so it's role is strickly amp.

The sound is pure and magical. No coloring but the staging and separation is the best my aging ears have ever heard.

Higher end than what your testing but an excellent higher mid-range configuration that simply delivers beautiful sound, (and the amp is only 24 watt)!

My speakers are custom built, (based on SEAS Exotics), and at 91db efficiency, let me hear if anything is amiss and so far, the only disappointment has been some the tubes I have purchased, but then that has also allowed me to find a combination that has had me in tears of joy.

Your idea works and delivers beautiful sound.


Grant Audio used to have the P-307, which is like the MkII 283 but has a phono input.

It's now unavailable but you should write and ask them about it.

You can get basically the same thing but without Grant branding and quality control at:
I have had great success with 2 Grant Fidelity tube buffers. The smaller 283 in my office system, and the MKII 283 in my main system. I've updated the tubes to cryo-treated, and use a decent power cable. I have them between the DAC and the Preamp.

I only use them between the digital sources, not analog, and the preamp. After all, that is what needs the most help. It works wonderfully, and only cost $350 with upgraded tubes for the MKII.

Another inexpensive option if you want to go preamp, is the Jolida JD5T. Tube preamp, with remote, for $425 new.

I am very grateful for all of your thoughtful responses, and am learning a lot! I have been away from all this for a few weeks due to a frantic new job with ungodly deadlines, and before reading some of the more recent posts here -- in fact not realizing they WERE here -- I acted on the Yaqin ms12b tube phono stage and line preamp, which arrived the other day. If it doesn't work for me, it can go on sale. I would like to have the money to do better than trying to cobble it together with my modest vintage SS receiver, but maybe that will come with time.

I've just begun to experiment (a wonderful way of not worrying about work!). What I have discovered: If I plug the Yaqin directly into my receiver's PRE-OUT MAIN-IN loop, all the receiver's tone and volume controls are disabled for the phono, which of course goes directly from the RIAA input on the Yaqin preamp to the solid state MAIN IN. Tone and volume do work for other sources, I guess because they go through the SS preamp before going into the Yaqin, and I do have the Yaqin volume control.

If I plug the receiver's TAPE OUT into the Yaqin LINE IN and the Yaqin output into the receiver's MAIN IN, resulting in a TAPE OUT-MAIN IN loop, the receiver's tone controls are bypassed for all sources and the receiver seems to act as a source selector without modifying the signal, so that might be the purest solution. But I may still need tone controls at this point.

So far, with the Yaqin going directly into the power amp--without the use of tone controls and the ability to temper the treble--I find it harsh and tinny, much more so than the SS receiver on its own--which I was trying to mellow and soften. (I am not yet a purist!) Of course, I still have new stock Chinese tubes in it, which are not supposed to be all that great.

On the other hand, if I put the Yaqin into the Marantz TAPE-IN TAP-OUT loop, where I have the advantage of the receiver's tone and volume controls, the sound is more pleasing--still not sure how much better it is than the plain ol' Marantz is, but maybe tube rolling, which I have never tried, might be the next step.

This is all quite confusing to me, and one day I may bite the bullet and go for an integrated tube amp. But in the meantime, what about just leaving the tube pre-amp in the tape loop, with access to the receiver's tone and volume controls? At least for now? Followed with better tubes fro the Yaqin.

Or can anyone think of a better configuration? Thanks, all, for sharing your knowledge and expertise.