(You can do it if you are careful with levels but.....)
I do the one preamp to another all the time.
I use one preamp to 'tube'ify' my digital sound, and that preamp feeds my main preamp.
I also have another preamp I use for the tubed phono section, and that preamp also feeds my main preamp.
Ny problems at all.
I would suggest playing with the combination of volume controls to find the best combination.
For the digital preamp, i find allowing my main one to be set to 1 o'clock and use the tube buffer preamp to adjust gain works best.
For the preamp with a phono section, i tend to max out that preamp volume, and keep it's gain set low. and use the volume on my regular preamp to adjust gain.
I have played with as many as three in line just to fool around. Two is no problem at all.
I want to run a mono signal through the one preamp to a solid state 300 watt monoblock and then to the sub and from there to all the woofers in my other speakers. With the other preamp I will send the signal through a tube amp to the mids and tweeters. I like the sound of solid state in the bass and tube in the mid/tweeter range. Just don't want to destroy anything in the process.
Luked. Yeah your idea is a good one. then you can control the volume of the sum a little better.
Have the sub preamp follow (or be connected from or after) the main channel one. then the main channel master control is all you usually need to move. But if you want to adjust the sub in relation to the main, then the sub pramp volume can be moved.
Connecting the second one via volume controlled output is best. If you use the line out, or tape out, everytime you change the volume on the main, your sub will need to be adjusted. (which is a PITA)
And yeah, maybe using two may cause a slight degredation of some theoretical signal. The thing is, if it does what you want, that is way better than somebody elses 'theory' hey!
I don't understand several things about this:
1)The woofers in the main speakers will presumably be handling much higher frequencies than a sub would normally handle. Assuming that the overall setup is intended to provide stereo (is it?), I don't see how it would make sense to provide a mono signal to those woofers. Driving a sub with a mono signal can be appropriate only because the frequencies it is reproducing are very low.
2)How are you generating the mono signal?
3)Assuming the sub is a powered sub (is it?), containing its own amplifier and providing a level adjustment, I think you are saying that the reason for including the second preamp is to allow level-matching between the woofers in the main speakers and the mid/hi drivers of the main speakers. Am I understanding that correctly?
4)Can you indicate the make and model number of the sub, which may help to clarify some other things I am uncertain about?
There are a couple of unique problems with the current set up. The Sub has a rythmic plate amp that produces a hum in the system when connected via RCA, the hum disappears when connected via speaker inputs. The mono signal will be generated via y output from the preamp going to the monoblock. The monoblock will connect via speaker wires to the crossover system in the rythmic plate amp with one feed going to the sub and one feed going to the woofers. If this produces distortion or an echo effect I may just run a mono feed to the back speakers from the sub. Again I have know idea what this will sound like I just do not want to destroy anything finding out.
The mono signal will be generated via y output from the preamp going to the monoblock.That will probably work ok, but if the preamp has particularly low output impedance sonic issues might result.
The monoblock will connect via speaker wires to the crossover system in the rythmic plate amp with one feed going to the sub and one feed going to the woofers.Again, providing a mono signal to woofers that have to handle frequencies into the mid-bass region (or even higher) will not sound good, assuming the overall setup is stereo.
The Sub has a rythmic plate amp that produces a hum in the system when connected via RCA, the hum disappears when connected via speaker inputs.You could most likely eliminate the hum in the RCA configuration by inserting a Jensen Iso-Max transformer into that path. Consult with them by phone for specific model recommendations.
Again I have know idea what this will sound like I just do not want to destroy anything finding out.As some of the others have said, you will not hurt anything, as long as you don't have both volume controls simultaneously turned up to unreasonable levels.
Elizabeth you were spot on and this does sound great. I only went from second preamp to sub to rear speakers making them mono and it did everything I needed. I did not mess with crossovers in each speaker to obtain the complete seperation of woofers, to much work at this time and I like the results of what I did. I can fine no deterioration in sound and the rears set at a lower volume then the front actually help with the sound stage versus the two sets in stereo which in my large room and old ears had a poor front to back seperation. Thanks for the encouragement. Bass is now extremely tight a sound I have always preferred.