No problem, this then will be 50kohms as seen by the Lightspeed
Cheers George
Witam wszystkich.
Bardzo dziękuję za odpowiedź, po podłączeniu w bi-ampingu napiszę jak to brzmi w porównaniu do wersji na jednym wzmacniaczu.
Pozdrowienia.
Bardzo dziękuję za odpowiedź, po podłączeniu w bi-ampingu napiszę jak to brzmi w porównaniu do wersji na jednym wzmacniaczu.
Pozdrowienia.
Yes, please do that and compare one versus two power amplifier inputs. Let us know what you hear. I have just added a parallel amplifier channel on three of eleven LDR channels, and although I have not tuned it, those 50K loads seem to be tracking well with the single 100K amps.
I asked a similar question on this outstanding website last year and a member suggested connecting a 100Kohm resistor in parallel to each single amplifier, if in fact volume tracking is affected.
Beyond the need to re-tune for my added drivers, it still sounds great over here.
I asked a similar question on this outstanding website last year and a member suggested connecting a 100Kohm resistor in parallel to each single amplifier, if in fact volume tracking is affected.
Beyond the need to re-tune for my added drivers, it still sounds great over here.
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I am contemplating the Lightspeed for use as an attenuator between my Conrad Johnson PV10 preamp and my NAD 2200 mono-blocks. Right now there is too much gain which renders the preamp useless. Can the output of the PV10 go into the lightspeed and the output from the lightspeed feed the mono-blocks?
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Yes no problem, the CJ is 650ohms and the Nad 25kohms, after you've done that, then just try the source/s into the Lightspeed and the Lightspeed into the Nad (leaving the CJ out) and see what you think, as the Nad is 700mV input sensitivity for full output, so you really don't need and active preamp at all because most sources give out over 2v.
Cheers George
Cheers George
Hi!
For the volume control potentiometer:
is it possible to use a 10k dual log pot instead of the 100k dual log pot?
Or:
use simulate by using a 100k dual linear pot and for each channel put 20k resistor over two of the leads?
/hk
For the volume control potentiometer:
is it possible to use a 10k dual log pot instead of the 100k dual log pot?
Or:
use simulate by using a 100k dual linear pot and for each channel put 20k resistor over two of the leads?
/hk
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Mayby I ought to add some information:
I’m building the dual mono version (third photo in post #1), the schematic uses a 100k dual log pot.
/hk.
I’m building the dual mono version (third photo in post #1), the schematic uses a 100k dual log pot.
/hk.
Volume level comes on too quick in my design, 100k log gives good range from zero to half then come on quicker for the second half.
Cheers George
Thank you George!
I guess that is comparing linear vs log pot. Correct?
Is it critical that the pot is 100k and not for instance 10k? IE is it possible to use 10k instead of 100k log pot without breaking the optocouplers.
Will the function be the same?
/hk
I guess that is comparing linear vs log pot. Correct?
Is it critical that the pot is 100k and not for instance 10k? IE is it possible to use 10k instead of 100k log pot without breaking the optocouplers.
Will the function be the same?
/hk
Almost.
You can use 10k but you won't like how quick it comes up, and no you won't break the LDR's, as the voltage to them stays the same if your full up or at min regarless of whitch pot/s you use.
Cheers George
Well, it’s been a minute, but Lightspeeds are now available for purchase again !
We have limited stock, but exactly the same as George’s original design.
Future releases & models will have added function, but for now we’re sticking with what we know works.
Happy Listening
Scott
We have limited stock, but exactly the same as George’s original design.
Future releases & models will have added function, but for now we’re sticking with what we know works.
Happy Listening
Scott
Have built the dual mono version. As volume control using a dual gang logarithmic Bourns, 91A2A-B24-D20/D20L, 20% Conductive Plastic potentiometer. 100kOhm, 1/4W. However, the channel accuracy is not god enough.
What potentiometer would you recommend with better channel accuracy?
What potentiometer would you recommend with better channel accuracy?
IMV Dual Mono (LED control path) does not have any advantages but does add complexity and another mechanism for mismatch being the pots themselves.
So you will be trimming out mismatch of pots and LDRs. This doesn't make sense from a good design perspective.
TCD
So you will be trimming out mismatch of pots and LDRs. This doesn't make sense from a good design perspective.
TCD
Use a linear dual pot, which has much better tracking, with a "law faking" resistor from the wiper to ground.
Adjust the value of the resistor to suit the desired taper.
https://www.diyaudio.com/community/threads/fake-law-log-pot.71951/
Adjust the value of the resistor to suit the desired taper.
https://www.diyaudio.com/community/threads/fake-law-log-pot.71951/
This is a great "pot" to use. It is a stepped attenuator using surface mount devices. It is very small and affordable. They track better than any pot I've ever checked. And they are pretty cheap!
eBay stepped attenuator
Stuart
eBay stepped attenuator
Stuart
Yes, I've used those stepped stereo log pots for years. It will track perfectly (within 1%).
Around $15 each on ebay. Don't let the price fool you, they are high quality and work great.
Available with round flatted shaft or knurled shaft, values 10k 20k 50k 100k.
Around $15 each on ebay. Don't let the price fool you, they are high quality and work great.
Available with round flatted shaft or knurled shaft, values 10k 20k 50k 100k.
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Very nice and log too, perfect for the stereo Lightspeed, wonder if they make a single in those for the dual mono Lightspeed?
And I imagine the smd resistors in them will handle more current than the carbon/plastic tracks can in the 25mm originals I used.
Cheers George
And I imagine the smd resistors in them will handle more current than the carbon/plastic tracks can in the 25mm originals I used.
Cheers George