Joshua Tree Attenuator, suitable input impedance for the 3-channel B22?
Aug 18, 2010 at 12:08 PM Post #61 of 71
Aug 18, 2010 at 12:26 PM Post #62 of 71
Huh, I thought it was like that from the top of my head. Looks like I was wrong. You didn't swap the signal and the gnd at the input by any chance, did you? That might explain why you're getting no sound. 
 
Aug 18, 2010 at 1:11 PM Post #65 of 71
Okay, I don't think that is right. lol Got a picture of the acutal wiring?
 
a) Whats the red lines on the top right?
b) Wiring should be (RCA) -> (in JTA out) -> (in B22 out) -> headphone...
 
Edit: ah E22... looking at the wiring diagram for J6 and J7:
pin 3 is the output from E22 to the input of JTA
pin 2 is the input that takes the output from JTA
and pin3 is ground.
 
Is this what you're trying to express in the diagram? Check if its correctly wired...
 
Aug 18, 2010 at 1:37 PM Post #66 of 71
Lil' Knight, look at the ε22 schematic.  If the diagram you posted represents what you think is the pin-order of the volume pot connections to the ε22 board, then it's wrong.
 
Also, you don't need those ground wires on the right (in blue).  The ε22 board's ground connection to the JT is sufficient.
 
Aug 18, 2010 at 9:14 PM Post #67 of 71


Quote:
 
Also, you don't need those ground wires on the right (in blue).  The ε22 board's ground connection to the JT is sufficient.

I'll take a look at the wiring again later today. Must be something wrong between the input and output.
 
I wired the JT basing on what I did with the RK27 but it's the ground wire that confused me.
 
 
Aug 18, 2010 at 11:16 PM Post #68 of 71

amb saved my life again :p can't believe I made such a noob mistake. I was too careless not rechecking the pins. The JTA now works correctly as it should. It does pop a little when the relays begin to click.
And yes, day and night difference from my RK27. Just like I'm listening to the Beta23 now :p

Currently using the Pico DAC as source and I don't it stress the JTA a lot. Going to modify the JTA to have fixed Zin for my tube source soon but I'm a happy camper now.
Quote:
Lil' Knight, look at the ε22 schematic.  If the diagram you posted represents what you think is the pin-order of the volume pot connections to the ε22 board, then it's wrong.

 
Aug 19, 2010 at 1:53 AM Post #70 of 71
Thanks. The JTA is acting strange though, the volume is sometimes high, sometimes low when I rotated the pot. The wiring might be loose somewhere, I think.
 
I'll report back when I receive the resistor set to mod the JTA.
 

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