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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.
vesuvio
newbee
4,767 posts
 
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.

FWIW
seattlehifi
70 posts
 
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.

Best,
Burt
vesuvio OP
5 posts
 
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.

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