| orthoefer |
I am in the process of building an audio controller based on the Twisted Pear Joshua Tree kit. The controller is housed in a chassis similar to my RevC monoblock amps posted elsewhere on this board. The controller functions as a very simple passive attenutator with 2 inputs. I plan on adding infrared remote volume control using Brian Donegan's "Twisted Pot" circuit and design. It's taken a long time to get where I am, but the project is far from complete.
As usual, the enclosure is from Lansing, the RCA's are made by Vampire (Michael Percy Audio), the toroid is from Plitron, the back plate is from Front Panel Express, the selector switch is from Grayhill (71 series that Peter Daniel recommends, available at Digi Key), and the knobs are from the guy in Hong Kong selling knobs on Ebay. Miscellaneous screws are from BoltDepot.com.
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| orthoefer |
Here is what I am working on for a circuit to drive a motorized potentiometer. It is essentially Brian Donegan's design.
The board measures 2" x 3" and will fit right below the input selector switch shaft. Note how the components are kept to the sides of the board to allow for clearance of the shaft.
This is my first use of Eagle to design boards, and a board house to manufacture the two sided board. Hopefully, I got it right. |
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| orthoefer |
A little progress... Here's my version of Brian's remote control card. The board is made by Protoexpress and seems to be excellent quality. Now I'm waiting on the proper sized transformer from Plitron.
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| Gooch |
Very nice work they look good all together. One question why are you using two JT relay boards I thought you only need one for single end?
Regards
Dave |
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| orthoefer |
| Good question. You are correct. Only 1 JT relay board is needed for SE input. I contemplated balanced inputs at first and ordered 2 relay boards. I kept the two 2 boards to maintain a "dual mono" configuration. Thanks for the feedback. |
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| orthoefer |
I changed to a 9v Plitron transformer, which seems fine for the project. One secondary powers the JT controller board and the other secondary powers my remote board. I just need to tidy things up, and I think I'm done. |
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| jleaman |
| I don't know how i missed this but SO NICE!! |
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| orthoefer |
I am mostly done.
If anyone is interested in my version of the remote board, I have one for sale ($30).
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| orthoefer |
| I was asked where certain parts for this project come from. The decoder IC is from Rentron, and the case is from Lansing. |
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| Arius |
Hi,
Very nice casework.
I am a little puzzled, Twisted Pear's website seem to have been de-registered or something so I can't check. So what you have is a pre-amp right? The relay board (Joshua Tree) is a relay-based log attenuator. So why add the IR remote controlled motorized pot? Seems to me like you have 2 volume controls???
Or if the relay board is for input selection, that's an awful lot of relays for 2 input channels. |
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| orthoefer |
| This project is really just a remote controlled attenuator--not really a preamp. The remote control pot provides a control voltage for the relay boards. The relay boards adjust their discrete resistances based on the control voltage. No audio signal passes through the motorized pot. This means the pot does not need to be of high quality. I hope this clarifies the role of the JT boards. |
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| Arius |
Ahhh, I understand now. Thanks for the clarification.
Nice work with the PCB too considering it's your first with Eagle. Hope everything worked out well for you.
The case is a little pricey from Lansing. It's like ~ $70, right? I like the knobs though. I might get some too. |
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| samoloko |
On the Brian scheme of potentiometer remote control pin 8 of sn754410 Is connected to 12V and you are connecting to 5V
what difference this make to the final result |
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| orthoefer |
| quote: | Originally posted by samoloko
On the Brian scheme of potentiometer remote control pin 8 of sn754410 Is connected to 12V and you are connecting to 5V
what difference this make to the final result |
Check out the discussion in Brian's thread (page 11 of the Joshua Tree discussion) after he posts the schematic. There are several posts about dropping the voltage from 12V to 5V. Essentially, the motor pot moved to quickly with 12V, so the voltage was dropped to 5V. Now everything is powered by one VREG and the circuit is a bit simpler. |
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| samoloko |
thx
indeed one 5V reg Is better (what sec voltage of traf you are using)
did you try what was the sound when using just a remote controled pot
I wonder if that project could use only one pic for receiving IR and making control voltage for relays
Because rentron chip comes with togle option you can use pin 3 for power on /off |
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| orthoefer |
| quote: | Originally posted by samoloko
thx
indeed one 5V reg Is better (what sec voltage of traf you are using)
did you try what was the sound when using just a remote controled pot
I wonder if that project could use only one pic for receiving IR and making control voltage for relays
Because rentron chip comes with togle option you can use pin 3 for power on /off |
I am using a transformer with 2 x 9V secondaries. The guys at Twisted Pear keep talking about a Uber Controller that would make the JT controller a little more elegant. |
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