TIME TO POST THIS AGAIN
To all the 69,000 odd members that have been looking at this thread, we are all obviously interested in passive pre's of some description, be they pots, switched resistors, transformers or the Lightspeed.
I believe we need a PASSIVE PREAMP forum of our own, not to be stuck here in the solid state (yuk) forum. To get our own PASSIVE PREAMP forum you should vote here.
http://www.diyaudio.com/request/
Under the Passive Preamp Heading section that I have started with the first vote.
Please take the time to do this and get us out out limbo.
Cheers George
To all the 69,000 odd members that have been looking at this thread, we are all obviously interested in passive pre's of some description, be they pots, switched resistors, transformers or the Lightspeed.
I believe we need a PASSIVE PREAMP forum of our own, not to be stuck here in the solid state (yuk) forum. To get our own PASSIVE PREAMP forum you should vote here.
http://www.diyaudio.com/request/
Under the Passive Preamp Heading section that I have started with the first vote.
Please take the time to do this and get us out out limbo.
Cheers George
VTL 5C10
Does anybody know where this vactrol can be purchased.
Thanks in advance.
Gajanan Phadte
Does anybody know where this vactrol can be purchased.
Thanks in advance.
Gajanan Phadte
Hi Gajanan,
I seem to be stalking you but are you sure that 400ohm min R is low enough?
You can get them from Allied nhttp://www.alliedelec.com/Search/ProductDetail.asp?SKU=980-0006&SEARCH=&MPN=VTL5C10&DESC=VTL5C10&R=980-0006&sid=45DA3A00200D617F&tab=specs
but they are $6.76 each!!
John
I seem to be stalking you but are you sure that 400ohm min R is low enough?
You can get them from Allied nhttp://www.alliedelec.com/Search/ProductDetail.asp?SKU=980-0006&SEARCH=&MPN=VTL5C10&DESC=VTL5C10&R=980-0006&sid=45DA3A00200D617F&tab=specs
but they are $6.76 each!!
John
How come you are looking at PerkinElmer? Is this the new favorate?
George is using Silonex NSL-32SR2S which is $2.4 each.
http://www.alliedelec.com/Search/Pr...SC=NSL-32SR2S&R=699-3011&sid=464B9B004703617F
George is using Silonex NSL-32SR2S which is $2.4 each.
http://www.alliedelec.com/Search/Pr...SC=NSL-32SR2S&R=699-3011&sid=464B9B004703617F
On ESP site the method for constructing a vactrol is explained. I think it is a guitar effect project IIRC.
Gajanan phadte
Gajanan phadte
Question..
This might be a completely silly question, but I'm seriously considering building one of these things, and the only question I have is, has anybody tried different color LED's, and has that had any effect on the resistance of the sensors at all?
This might be a completely silly question, but I'm seriously considering building one of these things, and the only question I have is, has anybody tried different color LED's, and has that had any effect on the resistance of the sensors at all?
Re: Question..
The devices most people are using contains both the LDR & the LED in one 4 legged package. This simplifies things in several ways including largely eliminating the effects of external light.
This does not answer the question that you asked but never-the-less I hope it is useful
mike
DrDyna said:
The devices most people are using contains both the LDR & the LED in one 4 legged package. This simplifies things in several ways including largely eliminating the effects of external light.
This does not answer the question that you asked but never-the-less I hope it is useful
mike
Aha!
Aha! Yes, that does answer one question that I had.
Perhaps some experimentation is in order, maybe with parts that don't generate their own light, in a sealed container with, say, blue, purple or green LED's. Perhaps even electroluminescent plates.
Just thinking out loud.
Aha! Yes, that does answer one question that I had.
Perhaps some experimentation is in order, maybe with parts that don't generate their own light, in a sealed container with, say, blue, purple or green LED's. Perhaps even electroluminescent plates.
Just thinking out loud.
Re: Aha!
Usually the Light Dependent Resistor (LDR) is optimised for a particular wavelength of light - yhis should be given on the datasheet - so it will have the strongest reaction to this wavelength. But I don't know how other light will effect it - maybe worth experiment?
John
DrDyna said:
Usually the Light Dependent Resistor (LDR) is optimised for a particular wavelength of light - yhis should be given on the datasheet - so it will have the strongest reaction to this wavelength. But I don't know how other light will effect it - maybe worth experiment?
John
Well - yes, if you are looking for something to think about this might be an interesting topic.....
.....but if you want a really great pre-amp just make this circuit as described ... 😉
.....but if you want a really great pre-amp just make this circuit as described ... 😉
appraisal
i have got one of these from george and it's bloody good. played with it a bit on and off over the last weekend and it really is so much better then any pre amp i have had before. in actual fact i have finally got the sound i am after - great mids and high frequencies, excellent bass.
probably better with my cd player then through my phono stage but am very happy with it for not much money.
would quite like to try another power supply so if anyone has any details of where i could buy or make one it would be appreciated
i have got one of these from george and it's bloody good. played with it a bit on and off over the last weekend and it really is so much better then any pre amp i have had before. in actual fact i have finally got the sound i am after - great mids and high frequencies, excellent bass.
probably better with my cd player then through my phono stage but am very happy with it for not much money.
would quite like to try another power supply so if anyone has any details of where i could buy or make one it would be appreciated
Re: appraisal
Glad your liking it.
John the simplest way of trying a different power supply would be a 12vdc battery, you know the ones that are in alarm systems about the size of a small brick you can recharge those.
This is the purest form of 12vdc you will get, but remember one thing with a battery, you have destructive amounts of current available from them, be very careful or you could blow your new Lightspeed Attenuator into orbit, REMEMBER ONE THING CENTRE PIN IS +++++++++ on 12vdc reg input of the Lightspeed.
Cheers George
spacejay said:
Glad your liking it.
John the simplest way of trying a different power supply would be a 12vdc battery, you know the ones that are in alarm systems about the size of a small brick you can recharge those.
This is the purest form of 12vdc you will get, but remember one thing with a battery, you have destructive amounts of current available from them, be very careful or you could blow your new Lightspeed Attenuator into orbit, REMEMBER ONE THING CENTRE PIN IS +++++++++ on 12vdc reg input of the Lightspeed.
Cheers George
colour of LED
I was experimenting with various LED and photoresistors and here are some results of making LDR manually:
-ordinary LED are not suitable since the intensity of light is not sufficient
- bright LED are much better
- lowest resistivity (50 Ohms) you can achieve with red LED
- however it is difficult to get higher resistivity than 4 kO - even 0.05 mA is too much light
- the best results I have got from yellow bright LED - the resistivity at 30 mA is 80 Ohms and it can grow up to 9-10 kO @ 0.03 mA
- the external light is the issue - be aware that you must keep it in the dark.
Ladislav
I was experimenting with various LED and photoresistors and here are some results of making LDR manually:
-ordinary LED are not suitable since the intensity of light is not sufficient
- bright LED are much better
- lowest resistivity (50 Ohms) you can achieve with red LED
- however it is difficult to get higher resistivity than 4 kO - even 0.05 mA is too much light
- the best results I have got from yellow bright LED - the resistivity at 30 mA is 80 Ohms and it can grow up to 9-10 kO @ 0.03 mA
- the external light is the issue - be aware that you must keep it in the dark.
Ladislav