LDR Active Preamp - does it exist?

What do you think - One alternative to solve the issue is to buy a match preamp. The match preamp specification is a bit worrysome for me because it output voltage is minimum 3V and max at 10V. I guess the reason it matches with the amp 4V input is because the preamp can deliver high voltage. The potential caveat is the preamp is less likely to compatible with most of other amplifiers. Preamp output at minimum 3V seems too high that may cause damage if the amp input voltage less than 3V?

After lightly reading this thread I thought I would comment on it. I have the Burson buffer and the Lightspeed LDR. It is a outstanding combo. It would solve your high input voltage issue. Just put it before the Lightspeed and after your source. I think you would be extremely happy with it, but each one has his own preferences. I got my buffer from Chris Johnson at Parts Connecxion and he told me that this Burson is the Cadillac of buffers. Have fun.

The Burson Buffer is your other option, but your are introducing it's sound into the mix. I would use it after the Lightspeed, between it and the amp. As your Oppo has great output impedance and it would do more good after than before the Lightspeed.

Cheers George

I think I will keep the Lightspeed - sorry Steve SCM. Burson buffer sounds like a good idea. The cost is around $700 which is not cheap for what it is but if it is truly solve the high voltage input issue with my amp, that may be worth it.

I looked a bit deeper and learn that Decware offers two buffers and one of those "ZSTAGE" model is adjustable output voltage using single ended triode gain stage. It can adjust from 0 to 5 V :)

http://www.decware.com/newsite/zstage.html

Consider that my amp input is 4V, it seems that it dials to between 4V to 5V would be ideal for my amps. If everything else being equal, SET gain stage is more of my liking than solid stage base Burson.

Have anyone using the ZSTAGE buffer before?

You would want to use the ZStage between your source and the Lightspeed. If your source is 2V you can use the buffer to add another 2 or 3V to the signal. Then use the Lightspeed to attenuate.

The idea of such a device that adds voltage to the signal is not unheard of. We actually make one using all passive parts and it also has a built in attenuator.