Digitally controlled preamp/headphone amp

Status
Not open for further replies.
BrianDonegan said:
Another tip for builders, since just about no one will have a proper crimping tool, is after you crimp the wires with pliers, gently add a (very small) drop of solder to the wire-pin connection to make it stronger and cleaner.


Good thing you threw in the "just about" in front of no one....
 
BrianDonegan said:
So, the pot is pretty easy. Hold the pot as shown in the attached pic, with the pins on the bottom. Wires are straight to the pin header. I'll post another pic with wiring for the trafo...


Now if I'm not mistaken the pot is a voltage adjusting device converted to a digital signal correct? If so wire "type" doesn't matter.. Correct assumption?
 
Correct troy, the pot only supplies a variable voltage to the ADC on the PIC, so just about anything will work fine as far as wire goes. No audio signal to the pot at all.
A bit off topic! As I said earlier, Russ is a man for the future😀
Remember Russ'ie-boy?
Sorry about being OT😀 😀 Sorry, could'nt help it😀

Steen😎
 
Beta Update

Have all the parts mounted to the board and will start testing once I get some cabling put together.

A heads up. Brian's labeling almost put me to sleep, it is so good. But the part labeled 7812 turned out to be a 7912. I hope this is a one time oops, but I did catch it before I soldered it in.

Other than that, remembering which places are not populated with caps caused a bit of frustration moving the electros, but all else went on board very easily.
 
Schematic

here it is:
 

Attachments

  • schematic.png
    schematic.png
    29.1 KB · Views: 1,772
Beta Running

OK, I had some spare time and threw together some jumpers and the amp runs great.

I must have read the pot hookup on post 158 wrong because it worked backwards. One more reminder why we always try it out first on cheap speakers.

First impressions are that it is hard to tell much difference in the my_Ref with or without it. Maybe a bit smoother with it in. No loss in the great imaging of the main amp.

Don't have time for pictures tonight but will see about later in the weekend.

Craig
 
Hi Jason,

The cost is largely depndant on the opamps. Final kit price is not set yet. If you use just one AD8620 it will cost right around $60. Add another 10-12 bucks if you want one for the input buffer. If you opt for two of the OPA2227 for the input/output buffers the cost is down in the fifties or so.

Add to the that the trafo and various connectors/switches/fuses/case and you have your price.

Cheers!
Russ
 
Russ White said:
Hi Jason,

TRhe cost is largely depndant on the opamps. If you use just one AD8620 it will cost right around $60. Ad anout 10-12 bucks if you want one for the input buffer. If you opt for two of the OPA2227 for the input/output buffers the cost is down in the fifties or so.

Add to the that the trafo and various connectors/switches/fuses/case and you have your price.

Cheers!
Russ

Id be interested in one to play with.. what is the totall cost with tranny and stuff.. ? im really loking for one that is remote with lcd that has

Input selector
Lcd read out
Remote
Volume selector Up/ Down
Power on off
I have the digi01 Volume pot using relays and love it.. Now to get one with a lcd and these functions.

The digi01 Pot.
 

Attachments

  • digi01.jpg
    digi01.jpg
    93.9 KB · Views: 1,492
Status
Not open for further replies.