Lightspeed Attenuator a new passive preamp

[georgehifi]

Hi fbee, Interesting to try if someone has the time here, in my case cost would be a issue, but then this would be counteracted by not having to be so critical on matching, and then how would it sound, interesting, wish there were more hours in the day.

As for the remote, have not tried this, again time constraints.
Cheers George

[udailey]

Audiodiy1
Nice job. I am glad its working well for you.
Frank
I am using 3 LDRs at each position right now. Well until yesterday with I removed one each from Shunt. I dont hear a sonic benefit. Maybe maybe a bit richer but I have to AB it some more to be sure. Unsure about THD.
Never tried or heard of anyone trying what you are talking about for control.
BTW I guess Dartzeel uses some 100 LDR per channel .
Uriah

[udailey]

Someone was asking about Balanced LDR sets. I have a few. Let me know if you are interested by PM or email.

[alazira]

Hi,

I was wondering if this would work:

http://www.diyaudio.com/forums/attac...1&d=1269112786

[udailey]

I wondered the same thing. Wondered if I could use ONE LDR for shunt and only have to match the series pair.
It works but the soundstage collapses into a tiny point right in the center of the two speakers.
Uriah

[georgehifi]

Originally Posted by alazira

Hi,

I was wondering if this would work:

http://www.diyaudio.com/forums/attac...1&d=1269112786

Trouble being you'll need one pot for the series ldr DC voltage control and then another pot for the shunt pot to earth. How will you logarithmically control the two and keep channel balance at the same time.
It will become even more user unfriendly than my production Lightspeed Attenuator is that has separate L & R volume controls, which is an option that some customers buy (because they have system imbalances) But is a pain to use, just like the Audible Illusions 3a Preamp I used to have.
Cheers George

[alazira]

Originally Posted by georgehifi

Trouble being you'll need one pot for the series ldr DC voltage control and then another pot for the shunt pot to earth. How will you logarithmically control the two and keep channel balance at the same time.
It will become even more user unfriendly than my production Lightspeed Attenuator is that has separate L & R volume controls, which is an option that some customers buy (because they have system imbalances) But is a pain to use, just like the Audible Illusions 3a Preamp I used to have.
Cheers George

Thanks for the replies George & Uriah,

How about a tri or quad pot?

One group for the LDR's and two others for shunts? I'm thinking the shunt isn't as critical and might be fine with regular pot instead of LDR's. Plus, no matching and can go to 100K.

Of course if it doesn't sound as good then no point...

[georgehifi]

All too much, and series + shunt quad matched LDR's as I do them, sound better than my old resitor+ldr or ldr+resistor MkI Lightspeed Attenuator. Just go to the trouble of matching quad set's and you won't look back.
Cheers George

[udailey]

If the shunt arent matched really well this will throw your balance from Left to Right off more dramatically at regular listening than if your series are not as well matched. Its the math that screws it up.
I am not saying dont do it. It would be fun and educational. Then you could remove to gangs of the pot and just run matched shunts with the second gang and see what the difference is. If you are prone to experiment this might be fun. If you just want the best sound and no confusion and consternation go with matched quads.
Uriah

[markusA]

It's time...
I've ordered a VCCS for balanced operation from Paul and matching LDRs from Uriah.
Plans for a balanced buffer is in the pipeline.