Ha! Thanks, I was looking for "Silonex" which I guess no longer exists -- Advanced Photonics seems to have bought their assets for $900,000 cash, and they're still losing money and have cut back salaries and cancelled 401(k) matching etc.
Hope they keep producing . . .
If that's true, I'd buy these while you can. Doesn't sound like a good situation.
I agree. Glad to hear Digi-key has them -- they're so close they're practically overnight by first class mail.
Final prototype before the real thing.
Small board is for rotary encoder & IR receiver & and display. It is 2.5" x 1.5" and communicates with the display via a 3-wire connection (including power) and with the LDR board via a 2-wire connection. Not shown is an LED connection to show status when a display is not connected.
Display (not shown) shows Volume level, Balance, Mute ON/OFF, LDR current in milliamps (can be turned off), and when calibrating, the status in percentage complete.
Encoder (not shown) has a screw terminal connection that matches the control board exactly so it can be connected rigidly to the board with pins and the control mounted to the front panel can support the entire assembly for a very small installation at the front, and the LDR controller can be mounted at the back close to the audio in/out jacks for an ideal layout.
LDR board is 2.5" x 3.25" and the LDRs are socketed for easy replacement. It is a stand-alone board that can use either a front end control board as above or alternatively, simply two standard 10K linear pots for Balance and Volume, and an LED to display calibration status, Mute ON/OFF, balance centered, and LDR status.
Now that the design is finalized, working on pricing.
Small board is for rotary encoder & IR receiver & and display. It is 2.5" x 1.5" and communicates with the display via a 3-wire connection (including power) and with the LDR board via a 2-wire connection. Not shown is an LED connection to show status when a display is not connected.
Display (not shown) shows Volume level, Balance, Mute ON/OFF, LDR current in milliamps (can be turned off), and when calibrating, the status in percentage complete.
Encoder (not shown) has a screw terminal connection that matches the control board exactly so it can be connected rigidly to the board with pins and the control mounted to the front panel can support the entire assembly for a very small installation at the front, and the LDR controller can be mounted at the back close to the audio in/out jacks for an ideal layout.
LDR board is 2.5" x 3.25" and the LDRs are socketed for easy replacement. It is a stand-alone board that can use either a front end control board as above or alternatively, simply two standard 10K linear pots for Balance and Volume, and an LED to display calibration status, Mute ON/OFF, balance centered, and LDR status.
Now that the design is finalized, working on pricing.
Attachments
They have not burned out while I've been using them. And with my board I can watch the current flowing through the shunt LDRs at all times and the current is pretty trivial except at the highest attenuation where I can hardly hear my system. At max attenuation the current ranges between about 3.5ma and 9.9ma depending on individual LDRs. However, the LDRs are exposed to outside inputs and thus vulnerable to error or defective equipment, and not everyone is good with a soldering iron. It's a very tight socket connection, and compact; I like it very well.
The other socket in this design is also a tight connection, gold plated on both sides, with a large contact area for each pin.
Speaking of connections, if you consider the typical wire-to-terminal connection, it's a stranded wire with the wires soldered together clamped in the terminal strip. The solder is prone to oxidation and the solder is prone to flattening under pressure -- both of which affect the quality of the connection. Better to solder the wire to a solid gold-plated pin and insert the pin into the terminal strip. This avoids both problems caused by the solder and gives a better long-term connection. Second best is copper wire without solder.
The other socket in this design is also a tight connection, gold plated on both sides, with a large contact area for each pin.
Speaking of connections, if you consider the typical wire-to-terminal connection, it's a stranded wire with the wires soldered together clamped in the terminal strip. The solder is prone to oxidation and the solder is prone to flattening under pressure -- both of which affect the quality of the connection. Better to solder the wire to a solid gold-plated pin and insert the pin into the terminal strip. This avoids both problems caused by the solder and gives a better long-term connection. Second best is copper wire without solder.
Last edited:
I have ordered 25 complete sets of boards -- LDR controller, rotary/IR controller, rotary control carrier, and the jumper board which is used only during calibration -- and the outfit who will manufacture them are ordering the parts.
Taking James Hill's advice, the jumper will be entirely out of the circuit during operation. In other words, there will be no jumper between the LDRs and the audio in/out connections, it is only used during calibration to connect the calibration circuit to the LDRs. Audio In/Out cables must be disconnected for calibration but it should be so rarely needed that will be a non issue.
After these sets are distributed I'm going to pause for a bit to get feedback and make whatever changes are necessary. I don't think there will be anything significant -- James has been listening to his board for about eight or nine months now and has reported only one occasion when the balance pot (he was using a volume pot and a balance pot, not a RE) didn't respond after it hadn't been moved for a long time, I myself have had no trouble at all with the latest software.
If possible, I want these boards to go to people who will try them out when they get them and give me good feedback.
Except for a box and hardware and the optional display and hand-held IR transmitter, this will be a complete LDR passive preamp with rotary encoder and infrared control. All you need to supply is 9~16VDC.
Taking James Hill's advice, the jumper will be entirely out of the circuit during operation. In other words, there will be no jumper between the LDRs and the audio in/out connections, it is only used during calibration to connect the calibration circuit to the LDRs. Audio In/Out cables must be disconnected for calibration but it should be so rarely needed that will be a non issue.
After these sets are distributed I'm going to pause for a bit to get feedback and make whatever changes are necessary. I don't think there will be anything significant -- James has been listening to his board for about eight or nine months now and has reported only one occasion when the balance pot (he was using a volume pot and a balance pot, not a RE) didn't respond after it hadn't been moved for a long time, I myself have had no trouble at all with the latest software.
If possible, I want these boards to go to people who will try them out when they get them and give me good feedback.
Except for a box and hardware and the optional display and hand-held IR transmitter, this will be a complete LDR passive preamp with rotary encoder and infrared control. All you need to supply is 9~16VDC.
I'm very interested in trying it - it will be my first time using LDR's in a passive preamp (I currently have a DCB1 in my setup).
Any idea of cost yet?
Any idea of cost yet?
Can you or James provide links as to where people can get the optional display and/or remote control?
Is calibrating difficult without a display?
Thanks...
Dear Wapo54001,
Having already tried LDR's myself, and being infatuated with their 'sound', but quickly realizing they need some form of current control for accuracy, I would greatly appreciate the opportunity to try out your LDR preamp in my system. My system is based around DIY valve/tube pre and power amps and DIY single driver fullrange speakers.
Simon
Having already tried LDR's myself, and being infatuated with their 'sound', but quickly realizing they need some form of current control for accuracy, I would greatly appreciate the opportunity to try out your LDR preamp in my system. My system is based around DIY valve/tube pre and power amps and DIY single driver fullrange speakers.
Simon
I know the cost of the boards and the non-processor parts; I need to factor in the processors and LDR modules. For this round I think, repeat think, it will about $220 or slightly less for the LDR board, the RE/IR board, calibration board, and the RE pot board, all completely professionally assembled. That's everything except the display which initially might be $50 for the two-line OLED display. That is very tentative and will be for this first round only.
You get the display from me, it is not an off-the-shelf display, it has been reprogrammed to suit my purpose. If you want to save money, the LED display will be adequate for all volume, balance, mute, and calibrate settings, albeit not nearly as informative as the display. If you want the milliamp readout of your shunt LDRs -- which draw the most current -- you will need the display.
For the IR control, any Sony TV or amplifier control with volume will do the volume and mute. Not sure about balance yet because there are so few balance-capable remotes out there. You can also program a universal remote for Sony codes and use that. It must be close to the most available remote on earth . . .
Calibrating is easy without a display. You unplug your audio cables, connect the jumper board, turn on power. Initial LED is solid, moderate blink during programming, very slow blink when programming is complete. You turn off power, unplug the jumper, plug in your cables and reapply power. Calibration takes about 12 minutes. Piece of cake.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.