Lightspeed remote control
Hi Troy and all,
For the record the dot on the capacitor ident is the negative terminal.
I do not have any photos of the infra red boards. If I get some free time this weekend I will photograph them and upload to photobucket with a link to this thread.
I monitor this thread regularly so if anyone has questions or problems with the VCCS and infra red boards post your questions on the thread for the benefit of all. Unless someone else provides an answer before I get chance to reply I will usually answer relatively quickly unless, of course, I am away on holiday.
Remember that the VCCS board is quite versatile as a controller. It can provide volume and balance control for series resistor/shunt LDR, series LDR/shunt LDR in single ended mode or balanced mode (with some circuit adjustments) from the preamp chassis front and/or the infra red remote control boards.
If the series resistor/shunt LDR mode is used then the series LDR LEDs need to be replaced with ordinary LEDs so the voltage controlled current sources will operate correctly instead of latching up.
I get regular enquiries for VCCS etc boards and modules, mainly, are they still available. I have another batch of 50 sets of boards in now and will keep restocking them as long as people keep asking for them.
Regards
Paul
Hi Troy and all,
For the record the dot on the capacitor ident is the negative terminal.
I do not have any photos of the infra red boards. If I get some free time this weekend I will photograph them and upload to photobucket with a link to this thread.
I monitor this thread regularly so if anyone has questions or problems with the VCCS and infra red boards post your questions on the thread for the benefit of all. Unless someone else provides an answer before I get chance to reply I will usually answer relatively quickly unless, of course, I am away on holiday.
Remember that the VCCS board is quite versatile as a controller. It can provide volume and balance control for series resistor/shunt LDR, series LDR/shunt LDR in single ended mode or balanced mode (with some circuit adjustments) from the preamp chassis front and/or the infra red remote control boards.
If the series resistor/shunt LDR mode is used then the series LDR LEDs need to be replaced with ordinary LEDs so the voltage controlled current sources will operate correctly instead of latching up.
I get regular enquiries for VCCS etc boards and modules, mainly, are they still available. I have another batch of 50 sets of boards in now and will keep restocking them as long as people keep asking for them.
Regards
Paul
Lightspeed Remote Control
Hi Troy,
Find post 2738. The front panel push buttons control the DS1802 digipot. The circuit diagram for VCCS shows the wiring of the front panel switches relative to the DS1802 chip. Remember that the DS1802 is floating above ground and the DS1802 analogue ground pin potential is actually 3v3 above the power supply 0 volt terminal. So do not connect any of pins 1 to 6 to the power supply 0 volt terminal. The connector pin numbers are shown on the circuit diagram and the board layout and there are two rows of pins 1 to 6. This allows the use of the front panel push switches and the Infra Red receiver in parallel so you can use either or both control methods in your system.
Regards
Paul
Hi Troy,
Find post 2738. The front panel push buttons control the DS1802 digipot. The circuit diagram for VCCS shows the wiring of the front panel switches relative to the DS1802 chip. Remember that the DS1802 is floating above ground and the DS1802 analogue ground pin potential is actually 3v3 above the power supply 0 volt terminal. So do not connect any of pins 1 to 6 to the power supply 0 volt terminal. The connector pin numbers are shown on the circuit diagram and the board layout and there are two rows of pins 1 to 6. This allows the use of the front panel push switches and the Infra Red receiver in parallel so you can use either or both control methods in your system.
Regards
Paul
Anybody tried the Lightspeed as an attenuator in a tube preamp yet?
I have got nearly all the parts I need for a 12B4 linestage now. Only missing a few parts like eg. volume control.
Will I need a grid resistor (between grid and ground), or can I skip it?
(Not sure if it is possible for a Lightspeed to "fail open".)
I have got nearly all the parts I need for a 12B4 linestage now. Only missing a few parts like eg. volume control.
Will I need a grid resistor (between grid and ground), or can I skip it?
(Not sure if it is possible for a Lightspeed to "fail open".)
Thanks,Bas!
Got it.
Btw. DHTROB has a blog entry regarding the Lightspeed. According to him, it beats everything he has tried up to now (TVCs, attenuators etc.) ... as far as I understand from the text.
Actually Dutch is not extremely different to understand for us Norwegians. Mix a bit of English, Norwegian and German, and you are ready to go.
|| DHTRob - Buizenversterkers en breedbandweergevers: Entree ||
Got it.
Btw. DHTROB has a blog entry regarding the Lightspeed. According to him, it beats everything he has tried up to now (TVCs, attenuators etc.) ... as far as I understand from the text.
Actually Dutch is not extremely different to understand for us Norwegians. Mix a bit of English, Norwegian and German, and you are ready to go.
|| DHTRob - Buizenversterkers en breedbandweergevers: Entree ||
Not sure how it's going to like the hot environment, with the production Lightspeed I go to great lengths to thermally couple all 4 ldr's together and then I pot them in hard wax, to keep any thermal drift at bay, inside a tube amp??
Cheers George
That is correct. DHTROB rates the Lightspeed best volume control he's ever used.
Friends of ours, a Norwegian chap with a Swedish wife told me the same. When their parents visit them over here in the Netherlands, they read the Dutch papers. (But the other way around does not work. We can't read nordic languages. Or I can't at least)
Will it fail open... well if they fail the LDRs go dark so max resistance. If only the series failed then you would send everything to ground through the LDR resistor. If the shunt failed then everything would go through the series resistor and if both failed you would have a 50MOhm voltage divider as both would be somewhere around 25MOhm.
Uriah
Uriah
What I am working on ..
Why discrete R/2R DAC and not PWM control for LDR ?
Because PWM puts a lot of noise on LDR !
I am wondering if 8 bits aka 256 position is enough ?
So first try with 16bits aka 65536 position (which I think is tooo much ).
Why discrete R/2R DAC and not PWM control for LDR ?
Because PWM puts a lot of noise on LDR !
I am wondering if 8 bits aka 256 position is enough ?
So first try with 16bits aka 65536 position (which I think is tooo much ).
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why use matched LDRs?
just use different steps sent to each LED to achieve perfect balance all the way through the whole attenuation range.
and then use different steps to actually change the balance.
Store the required steps in a look up table.
Ok your idea for new construction ,
but my work is to make for already build Lightspeed attenuator a way of controlling by IR and add-on for source selection by replacing the poti for volume changing only .
Never the less I have also this idea of using not matched LDR and a routine for calibrating the two channel first time and store into a lookup table , so even a balance is possible to implement.
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