Thanks for the suggestions panelhead. I doubt a linear pot would help, since with my fixed output SACD player, I am loud at about three clicks off full attenuation. My tuner and phono preamp have adjustments for output and I can get more rotation out of the volume control. It would be nice to have more adjustment.
In these figures and graphs that are posted they are talking about input voltages of 60 and 100 volts, for the distortion figures to become significant, the higher the volts the higher the distortion and this is only happens when the LDR's have been turned on at their hardest, either at max volume or at zero volume, and it's second harmonic in nature which as we all know with Triode SET amps can be very pleasing to the ear, sometimes giving 3% second harmonic.
It's all a mute point as most of us are feeding CD level at 1 to 2 volts and the volume will hardly be at max or min, and even if it were, a little second harmonic is very nice to the ear.
I'm not trying to turn you guys away from bulk buying the NSL32SR3S instead of the NSL32SR2S, it's that I think you need to sample them before outlaying big bucks on a bulk buy on ones that haven't been tried yet, you see the off resistance is 25megohm for the 32SR3 and only 5megohm for the 32SR2, this itself looks to me like it could be disaster to be able to match and get both channels to track. As well as the on resistance is is also higher (worst case 3 x higher) and may not go down to an exceptable minimum level.
Cheers George
It's all a mute point as most of us are feeding CD level at 1 to 2 volts and the volume will hardly be at max or min, and even if it were, a little second harmonic is very nice to the ear.
I'm not trying to turn you guys away from bulk buying the NSL32SR3S instead of the NSL32SR2S, it's that I think you need to sample them before outlaying big bucks on a bulk buy on ones that haven't been tried yet, you see the off resistance is 25megohm for the 32SR3 and only 5megohm for the 32SR2, this itself looks to me like it could be disaster to be able to match and get both channels to track. As well as the on resistance is is also higher (worst case 3 x higher) and may not go down to an exceptable minimum level.
Cheers George
I think we can agree that the region of interest is between 0.2V to 2V, which converts to -15dBu to +6dBu (?).
Even in the case of a passive preamp without buffer, if your power amp has a JFET balanced input with lowish capacitance, you can live with 22k input impedance without problem, IMHO.
There is no universal truth. We are lucky enough to freely choose what we think suits best.
Patrick
Even in the case of a passive preamp without buffer, if your power amp has a JFET balanced input with lowish capacitance, you can live with 22k input impedance without problem, IMHO.
There is no universal truth. We are lucky enough to freely choose what we think suits best.
Patrick
Patrick, do some serious looking at the dark and light max and min resistances, you will have trouble getting even close to your wanted .5db channel match.
I would hate to see you and others on this thread get burnt bulk buying these, and find you cannot channel match them. I,ve played around with the Lightspeed now for some 30 years i know what to expect, imagine the same dual stereo potentiometer thats log at 25megohm, then you'll have an idea about channel maching with these, it's hard enough with the 5meg NSL32SR2S let alone 25meg. I've said enough, and leave you to your own peril.
Cheers George
I would hate to see you and others on this thread get burnt bulk buying these, and find you cannot channel match them. I,ve played around with the Lightspeed now for some 30 years i know what to expect, imagine the same dual stereo potentiometer thats log at 25megohm, then you'll have an idea about channel maching with these, it's hard enough with the 5meg NSL32SR2S let alone 25meg. I've said enough, and leave you to your own peril.
Cheers George
George,
Many thanks for your advices and for sharing your practical experiences with these devices. It has never been my intention to argue for one device or another, but I put the case up for the sake of open minded technical discussion, hopefully for the benefit of us all.
And maybe I did not make it clear that I am looking at the devices in a different application to that you posted here. I only need to match between 10k to 150 ohm.
Patrick
Many thanks for your advices and for sharing your practical experiences with these devices. It has never been my intention to argue for one device or another, but I put the case up for the sake of open minded technical discussion, hopefully for the benefit of us all.
And maybe I did not make it clear that I am looking at the devices in a different application to that you posted here. I only need to match between 10k to 150 ohm.
Patrick
Well then if that's the case for you then good, I hope it turns out ok.
But please advise others who are going to bulk buy in with you, and who will most probally use as I've designed it, to get the NSL32SR2S, so they can get a good result for their trouble building it and money they spend.
Cheers George
But please advise others who are going to bulk buy in with you, and who will most probally use as I've designed it, to get the NSL32SR2S, so they can get a good result for their trouble building it and money they spend.
Cheers George
George,
As no one in the US or Canada is volunteering, I doubt if there is going to be a group buy. It does not make sense to do it from here, with 30% import tax from the US.
And the 18 left at Allied as mentioned by George (Panelhead) are all NSL32SR2 anyway. NSL32Sr3S is not available either from Farnell or Allied, only the unsorted version.
I tried contacting Silonex and got no reply. I guess they are not interested in selling 100 pcs or so direct.
Patrick
As no one in the US or Canada is volunteering, I doubt if there is going to be a group buy. It does not make sense to do it from here, with 30% import tax from the US.
And the 18 left at Allied as mentioned by George (Panelhead) are all NSL32SR2 anyway. NSL32Sr3S is not available either from Farnell or Allied, only the unsorted version.
I tried contacting Silonex and got no reply. I guess they are not interested in selling 100 pcs or so direct.
Patrick
Patrick, email Margy Manganiello at Silonex she'll look after you.
mmanganiello@silonex.com
Also I think that the NSL32SR2 the S (sorted) weren't that sorted anway, but you will if you state you want the same letter group get all the same batch at least. ABCDEForG
Cheers George
Just looked, Allied have 1500 of the NSL32SR2, try to see if they have the same batch letter on them.
mmanganiello@silonex.com
Also I think that the NSL32SR2 the S (sorted) weren't that sorted anway, but you will if you state you want the same letter group get all the same batch at least. ABCDEForG
Cheers George
Just looked, Allied have 1500 of the NSL32SR2, try to see if they have the same batch letter on them.
serengetiplains said:
What the 4 led's consume at full power, make that 2 led's, as 2 go to max the other 2 go to min and they are for memory 25ma each so anything above 50ma should do.
The regulated 12vdc wall wart that comes with the unit is 300ma, bit of overkill. And the 5 volt secondary regulation inside the Lightspeed is a 1amp for memory again massive overkill.
Cheers George
I,ve done a bit of homework for you guys who want to build your own, and from the Perkin Elmer ones this is the one I would recomend the VTL5C3, it has a good light and dark resistance range being 1.5ohm to 10megohm just watch the current consumption of the led as it can be as high as 40ma higher than the NSL32SR2S, here is the data sheet on it, you will have to match these as well to get good channel balance.
Cheers George
Cheers George
George, I actually had some VTL5C3s on hand (they are a component in Elgar line conditioners, which I use). I tested a handful and couldn't get the resistance below ~800 ohms, this at 40mA, if I recall correctly. Any idea what gives?
I'm personally going to build a Silonex variety of the Lightspeed pre. Thanks, George, for the information you've shared. It should be a fun and worthwhile project.
I'm personally going to build a Silonex variety of the Lightspeed pre. Thanks, George, for the information you've shared. It should be a fun and worthwhile project.
serengetiplains said:
That's weird Tom, at 40ma you should get them down to 1.5ohms (so the data says), if yours were previously used for something else they may be out of whack now, by being over stressed or something or bad from the factory.
I know from experience that these things take no funny bussiness being done to them to send them wacko. They are fine if treated by the book, but go crazy if sneezed on.
Or Perkin Elmer are giving false data specs.
Also I noticed when soldering them you have to be fast, too much soldering heat has sent a couple wacko on me and that's with a heat sink clip attached to the legs
Cheers George
George, I was testing new units. They all measured about 800 ohms at max. current; the resistance would then begin to climb in most units when > max. current was applied. In my test setup, I used a 1K-ohm resistor in series with the LED and increased voltage very slowly on a 60V bench supply. I measured resistance with one multimeter, current with another inserted in series with the LED. I sent an email to Perkinselmer about these results, but no reply.
Was my test setup improper?
Was my test setup improper?