Hi Ben,
Yes they are going to work well with 100k dual pots. I am off of the single pot bandwagon and anyone having success with the single pots should try a dual pot. I think the difference may or may not be heard depending on the synergy of your system but the impedance curves are better with dual pots of any value, best so far with 100k. The original schematic as GeorgeHIFI showed us is still working better than any mods I have tried. However if you want to INCREASE impedance than stick a 10-30ohm resistor inbetween the power supply and the control pot in series with the 5VDC. The difference is huge with every few ohms of increase so a trim pot might even be a good thing to try there.
Mine sounds great with that single gang but I will be switching it out after my experiments.
If you are happy with the impedance as it is then leave out that series resistor. Its easy to try.
Ben, email me at diyldr@gmail.com
Uriah
Yes they are going to work well with 100k dual pots. I am off of the single pot bandwagon and anyone having success with the single pots should try a dual pot. I think the difference may or may not be heard depending on the synergy of your system but the impedance curves are better with dual pots of any value, best so far with 100k. The original schematic as GeorgeHIFI showed us is still working better than any mods I have tried. However if you want to INCREASE impedance than stick a 10-30ohm resistor inbetween the power supply and the control pot in series with the 5VDC. The difference is huge with every few ohms of increase so a trim pot might even be a good thing to try there.
Mine sounds great with that single gang but I will be switching it out after my experiments.
If you are happy with the impedance as it is then leave out that series resistor. Its easy to try.
Ben, email me at diyldr@gmail.com
Uriah
A product of the age?
It seems to me that if you feel that George deserves consideration from you using his circuit then you should clear your conscience and send him some money.
It would also seem that if he thought Uriah was doing something wrong he would let it be known.
IN ADDITION, one would have to believe he would take down the web page describing his circuit if he had a problem with what Uriah and the rest of us are doing.
Do you think it would be more equitable if all of us bought one hundred devices from ALLIED and found our own matches? Would this somehow be fairer to George?
I suspect if Uriah was selling a usable product or he was supplying someone with sufficient devices to go into production, it might be different.
Maybe Uriah should add a dollar to the cost and, like Peter Daniel, send George a fine bottle of wine at the end of the group buy? There could be a box to check volunteering to pay the extra dollar for such a fund?
The possibilities are endless.
Maybe every time someone builds a simple PAS style phono amp they should send a small stipend to the estate and heirs of David Hafler?
When you install a driver in a box who gets the honoraria?
I am getting confused.
It seems to me that if you feel that George deserves consideration from you using his circuit then you should clear your conscience and send him some money.
It would also seem that if he thought Uriah was doing something wrong he would let it be known.
IN ADDITION, one would have to believe he would take down the web page describing his circuit if he had a problem with what Uriah and the rest of us are doing.
Do you think it would be more equitable if all of us bought one hundred devices from ALLIED and found our own matches? Would this somehow be fairer to George?
I suspect if Uriah was selling a usable product or he was supplying someone with sufficient devices to go into production, it might be different.
Maybe Uriah should add a dollar to the cost and, like Peter Daniel, send George a fine bottle of wine at the end of the group buy? There could be a box to check volunteering to pay the extra dollar for such a fund?
The possibilities are endless.
Maybe every time someone builds a simple PAS style phono amp they should send a small stipend to the estate and heirs of David Hafler?
When you install a driver in a box who gets the honoraria?
I am getting confused.
Well if you think about it this thread (which even takes its name from his product) wouldn't exist if it wasn't for George reluctantly releasing his design. It's not that I think anyone is doing something wrong but without the years of development that George has done on this product and releasing it in the public domain then maybe Uriah wouldn't be matching LDR's for us or us building dirt cheap LDR pre-amps.
It just struck me that we are all "taking" and benefitting here from Georges years of development and frustration and he is the one who appears to be getting very little out of it. I have not built a Lightspeed LDR but just thought after reading through these threads that it seems to take a lot for granted. Just my take on it.
George goes after people who try to patent it not because its his but because they have no right to claim it. Its prior art, its been used in musical instruments for decades. What else to you think light variable resistors that are called Audiohm on the manufacturers website are for? For pots. Check out the circuits on their website. You will find a near duplicate. Build it however you want you are not stepping on anyones toes.
Uriah
Uriah
12VDC 1A psu
Uriah,
my voltage divider just burn out when reducing 48VDC to 24VDC in my LSA psu board....now thinking to do a simple regulator board from a 12VDC 1A (regular charger)supply to a 5VDC using 7805 reg. but I'm still worried that high current might burn the LDRs...i need some advice here...anybody....
Uriah,
my voltage divider just burn out when reducing 48VDC to 24VDC in my LSA psu board....now thinking to do a simple regulator board from a 12VDC 1A (regular charger)supply to a 5VDC using 7805 reg. but I'm still worried that high current might burn the LDRs...i need some advice here...anybody....
Everyone else,
GB is over. I am building a new testing fixture for quicker testing. It will test twice as many at one time.
So from this point on this particular thread for GB is closed.
Lightspeed questions please see the Lightspeed thread. If you need LDRs anyway please feel free to contact me and I will put you on my waiting list and you will be first to receive LDRs when new batch is tested. I expect this to be before Christmas and will be testing 1000 LDRs so there will be plenty to go around and hopefully I will get some time to work on other projects since I will have lots of LDRs tested, matched, and in inventory for you guys. Then hopefully we can get rid of the very long wait period many of you have had to endure.
Now assuming all goes will with test fixture I might have some ready before Christmas but lets not hold our breath.
Uriah
GB is over. I am building a new testing fixture for quicker testing. It will test twice as many at one time.
So from this point on this particular thread for GB is closed.
Lightspeed questions please see the Lightspeed thread. If you need LDRs anyway please feel free to contact me and I will put you on my waiting list and you will be first to receive LDRs when new batch is tested. I expect this to be before Christmas and will be testing 1000 LDRs so there will be plenty to go around and hopefully I will get some time to work on other projects since I will have lots of LDRs tested, matched, and in inventory for you guys. Then hopefully we can get rid of the very long wait period many of you have had to endure.
Now assuming all goes will with test fixture I might have some ready before Christmas but lets not hold our breath.
Uriah
Still 2 matched ldr's?
Hello Uriah,
I have ordered a set of 4 for a normal single ended control.
And I know you have finished this group buy, but do you have a set of onlt 2 matched LDR's left?
Want to try this in the feedbackloop of a TP2020 to avoid another capacitor in the chain.
Kind regards,
Rick
Hello Uriah,
I have ordered a set of 4 for a normal single ended control.
And I know you have finished this group buy, but do you have a set of onlt 2 matched LDR's left?
Want to try this in the feedbackloop of a TP2020 to avoid another capacitor in the chain.
Kind regards,
Rick
Rick,
No more matched. I am working on a few boards that will allow me to match at a much faster rate and with even improved accuracy.
For your feedback loop dont use matched anyway. Just shoot me an email telling me how many you need and I will send them to you for 1.70 each plus shipping. Then simply put them in the feedback loop and use a trimmer to get the right value. Trim them before you put them in the loop. Might be hard to measure in the loop since they are parallel with part of the amp so you wont get a perfect read. Well, I have ideas for this to and if you want you can send me your phone number and we can chat about it. But either way I think its a nice idea.
Uriah
No more matched. I am working on a few boards that will allow me to match at a much faster rate and with even improved accuracy.
For your feedback loop dont use matched anyway. Just shoot me an email telling me how many you need and I will send them to you for 1.70 each plus shipping. Then simply put them in the feedback loop and use a trimmer to get the right value. Trim them before you put them in the loop. Might be hard to measure in the loop since they are parallel with part of the amp so you wont get a perfect read. Well, I have ideas for this to and if you want you can send me your phone number and we can chat about it. But either way I think its a nice idea.
Uriah
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