I take it the system is exactly the same, nothing has changed to vary the system gain?
If so and the difference you get (gets loud very quickly) is happening in both channels, then the dual 100kohm log pot has gone faulty, replace it.
Cheers George
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Hi George, that was my thoughts as I couldn't think of anything else. Everything else in the system is as was. Thanks for your help.
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Sounds like either the wiper on the pot or the surface that the wiper rides on has oxidized. It can be cleaned with some electronics cleaner spray, but it will only oxidize again. As George indicated, I'd replace it with one that is of higher quality.
Hi George, me again. I seem to remember that someone some years ago posted a schematic for a balanced LA. Not sure if this was you or if you are aware of it?
Don't have it anymore, as they don't stay calibrated over time, just use xlr to rca adapters, if you only have xlr on your components.
Cheers George
Hello George
I am always delighted since 2 years of the lightspeed it orders 2 blocks formerly with tubes of 1984 with RF7 lll.
I'm going to buy Klipsch Belle, but they're a little light on the bass, that's where I need your advice: how can I connect a subwoofer in parallel?
Yours sincerely
Rodolphe
I am always delighted since 2 years of the lightspeed it orders 2 blocks formerly with tubes of 1984 with RF7 lll.
I'm going to buy Klipsch Belle, but they're a little light on the bass, that's where I need your advice: how can I connect a subwoofer in parallel?
Yours sincerely
Rodolphe
My Lightspeed started to develop a crackling noise on the left channel. Any idea what could it be? Thanks.
Disconnect the source inputs and see if the noise is gone. Is the noise present if the volume is at minimum?
Yes the noise is always present. I currently put a different preamp and is dead quiet.
Is this a production "Lightspeed Attenuator" or a diy one?
As the led/ldr's in the production Lightspeed Attenuator can't make a crackling noise, not even if the front volume pot is bad.
It must be a bad interconnect connection or the rear rca sockets have a loose center pin contact, check this get an old rca plug break off the outside contact so you only have the pin, and see if it's a loose fit in all 4 of the rca sockets on the back.
Cheers George
Hi George. It is a production Lightspeed. I will try what you suggesting and will report back. It is only doing it only in the Left Channel out. If anything I think I have a spare RCA jack. Thank you.
If that fixed it, then they have weak pressure inside for the center pin of the rca plug, re-new all 4 of the rca panel sockets, with good quality ones.
I have seen slightly oversized center pins on interconnects, and these stretch the inside of the socket, so when a correct size one is inserted you get this problem.
Cheers George
It just occurred to me since I'll be doing this project this weekend with PC817C LDRs that are relatively very cheap. Would doubling the signal LDR in parallel help with achieving a lower resistance and thus getting the volume closer to zero? Would the shunt LDRs have to be doubled as well?
Scratch that with the PC817C. Couldn't get it below 3K resistance. Can't source L-32SR2S, except from one shop in AU, and getting and sorting through L-32SR2 would still be pretty expensive for 40 of them. So I'll be trying LCR-0203 which I can get locally for about $0.75 each. The spec says it'll go down to 50 ohms at 20ma, so if I am lucky and can get 2 quad matches, I'll be able to bring the total resistance down to 25 by running them in parallel.