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Old 12th March 2011, 08:04 PM   #4051
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Udailey, thanks for the quick reply ! Also here is a link to the preamp I have and hope to up-grade ect.... Cary/AES - AE3 Linestage Help Needed !
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Old 12th March 2011, 09:50 PM   #4052
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Originally Posted by thor61 View Post
Can the Light-speed be configured to replace a 100K pot in a tube preamp ? If so how, and are there kits available ?
........and the good news is that with a 6-7k LDR shunted from grid to ground, your tube preamp will be quieter than with the 100k pot. Just be sure to install a large value resistor from grid to ground (assuming your preamp is grounded grid) so that the grid leak function is maintained when the LDRs are off. 1M is probably an absolute maximum, 470k is a safe bet.

Stuart
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Old 25th March 2011, 05:53 PM   #4054
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Thumbs up WOW. Thank you.

Just want to thank George and Uriah. The idea is fantastic and building attenuator from The Lighter Note kit was fun even for the first-timer like me. The sound improvement comparing to the pot in Benchmark DAC is just unbelievable. I must say I did a little tweaking: I put LDRs in separate boxes that can be attached directly to the power amp inputs.
As I mentioned, I am noob therefore my question: When I power off the attenuator the volume goes up. I checked resistance on RCA connectors with attenuator powered off. Between RCA center connectors it is 192K and between outer sides is 0R. No connection between inner and outer sides. Did I something wrong or this is quite normal
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Old 25th March 2011, 06:49 PM   #4055
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It is like that for me also.
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Old 25th March 2011, 08:13 PM   #4056
Marra is offline Marra  United Kingdom
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When I power off the attenuator the volume goes up. I checked resistance on RCA connectors with attenuator powered off. Between RCA center connectors it is 192K and between outer sides is 0R. No connection between inner and outer sides. Did I something wrong or this is quite normal[/QUOTE]

I believe its something to do with the LDR's going to a high impedance and someone does explain it [ Paul Hynes I think ] and its buried somewhere in this post. Why do you turn off the attenuator before the power amp?
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Old 26th March 2011, 01:08 AM   #4057
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When power is pulled from all production Lightspeed Attenuators the volume will go up a couple of dB for a second or two then go down to almost zero.

Cheers George
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Old 26th March 2011, 01:39 AM   #4058
udailey is offline udailey  United States
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Glad you guys are enjoying it. Even though this is a LDR thread and I am heavily involved in it, lets please keep it to George's circuit. If you have Lighter Note questions please feel free to email me. I sincerely enjoy helping guys out and its no bother at all if I have to answer the same question a bunch of times.
Your question about volume is relevant to George's circuit as well, though.
What is happening is that the series LDRs are using an extremely small amount of power and the shunt LDRs are using relatively higher amount of power. When you turn the circuit off the amount of power available for a short time to the LDRs quickly grows to much less than the shunts need to stay at the resistance they are at. The series need near nothing at this point to keep their resistance so they increase in resistance much slower, relatively, than the shunts. Since this attenuator is a voltage divider... when the shunts increase in resistance faster than the series then the volume increases.
Just turn off the LDR attenuator last or just leave it on. Both circuits use a tiny tiny amount of power. If you want to only use less than a mA when not listening then just turn to mid volume and leave it there. You dont need to turn them off. The nice thing about leaving them on is that there will be no surprises when you turn on the amp.
Uriah
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Old 26th March 2011, 09:51 AM   #4059
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Default RE: Volume level when powered off.

Thank you all very much for the answer. I was just concerned whether I did everything according to the design. For me this is not a big problem because my switch in attenuator also turns on my power amps.So unless someone pulls out the power cable from attenuator while playing music or resistance raise in LDR's did not catch up with the time delays for the amps relays everything should be OK. Anyways, I am very exited with the results and just wanted to thank you again.
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Old 3rd April 2011, 04:41 AM   #4060
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Quote:
Originally Posted by Alex Zhyk View Post
Just want to thank George and Uriah. The idea is fantastic and building attenuator from The Lighter Note kit was fun even for the first-timer like me. The sound improvement comparing to the pot in Benchmark DAC is just unbelievable. I must say I did a little tweaking: I put LDRs in separate boxes that can be attached directly to the power amp inputs.
As I mentioned, I am noob therefore my question: When I power off the attenuator the volume goes up. I checked resistance on RCA connectors with attenuator powered off. Between RCA center connectors it is 192K and between outer sides is 0R. No connection between inner and outer sides. Did I something wrong or this is quite normal
I had heard the LDR against the Benchmark HDR, like you say, it is simply unbelievable - better dynamics/transient attack & transparency.
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