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LDR Active Preamp - does it exist?

I am using passive LDR (Light Dependent Resistor) volume control LightSpeed Attenuator. As much as clarity and all the good stuff about this little preamp, I wish I can have some gain for my low sensitivity amplifiers. Is there any existing active preamp using LDR volume control?
nguyen787
wilsynet's avatar
wilsynet
264 posts
 
The Lightspeed LDR is wonderful provided your source and amplifier are appropriate for a zero gain, zero buffering preamp.

Either find a source that outputs closer to 4V, find an amp whose sensitivity is closer to whatever output voltage of your source, find another way to either add gain or lower sensitivity, or get an active.

I happen to think the Burson Buffer is a reasonable try to add gain to your system. It's actually what you're looking for, isn't it? An active, with gain and LDR volume control. The Burson Buffer adds 6db gain, and your Lightspeed LDR acts as volume control.

Having said that, an LDR is not the only means to deliver great sound, I happen to think the Coincident Statement Linestage and TRL Dude are better than the Lightspeed. But if your source and amplifiers are appropriate, I'd agree that there may be nothing better at the price point of the Lightspeed LDR.
nguyen787 OP
52 posts
 
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?
marqmike
847 posts
 
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.
georgehifi's avatar
georgehifi
10,312 posts
 
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
nguyen787 OP
52 posts
 
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?
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