Aegis DIY Tube Headphone Amplifier
May 5, 2024 at 3:47 AM Post #2,386 of 2,397
May 5, 2024 at 12:05 PM Post #2,387 of 2,397
Could someone please tell me what the manufacturer's reference corresponds to the Alps Blue Velvet RK27 20K Stereo?
Apparently the European Mouser may have this potentiometer and not run the risk of getting a fake... Is it logarithmic?
Thanks
 
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May 5, 2024 at 1:46 PM Post #2,388 of 2,397
Could someone please tell me what the manufacturer's reference corresponds to the Alps Blue Velvet RK27 20K Stereo?
Apparently the European Mouser may have this potentiometer and not run the risk of getting a fake... Is it logarithmic?
Thanks
By coincidence, I am just searching for the potentiometer (and other components) today. I will order this one from Farnell, as I already have some other stuff to order anyway. Farnell order code: 1191722, manufacturer part number on Farnell: STRK27102. If someone else can also confirm this is the correct one, just so I am not mistaken.
 
May 5, 2024 at 1:50 PM Post #2,389 of 2,397
By coincidence, I am just searching for the potentiometer (and other components) today. I will order this one from Farnell, as I already have some other stuff to order anyway. Farnell order code: 1191722, manufacturer part number on Farnell: STRK27102. If someone else can also confirm this is the correct one, just so I am not mistaken.

That looks to be correct.
 
May 6, 2024 at 1:19 AM Post #2,390 of 2,397
If that is anodized, note that the anodized layer is not conductive. If the mating faces of the side panels and the top plate were not masked and are completely anodized, you will need to sand / grind away some of the anodized layer to expose the underlying metal such that the side panels make ground connections with the top and bottom panels. You will have to do the same on the underside edge of the top and bottom plates, again, a metal-to-metal connection. Also, at the two holes where ground connections are made to the chassis, you will need to sand / grind away the anodized layer on the interior. All of this can be done with a Dremel tool.

I don't think its anodized. Its just barely brushed metal.
 
May 6, 2024 at 5:08 AM Post #2,391 of 2,397
I don't think its anodized. Its just barely brushed metal.

If it's just brushed uncoated aluminum then that's fine, not sure what you discussed with Dave. You can always check using the continuity setting of your multimeter to see if it's conductive.
 
May 6, 2024 at 5:20 AM Post #2,392 of 2,397
If it's just brushed uncoated aluminum then that's fine, not sure what you discussed with Dave. You can always check using the continuity setting of your multimeter to see if it's conductive.
I was just thinking the same thing about the MM. My new chassis had 4 separate aluminium panels and I used some stranded wire with locking washers etc to link them all to earth and did the continuity check you described! Just to be sure!
 
May 6, 2024 at 7:22 AM Post #2,393 of 2,397
If it's just brushed uncoated aluminum then that's fine, not sure what you discussed with Dave. You can always check using the continuity setting of your multimeter to see if it's conductive.

Wouldn't you want some sort of anodizing on it? Straight brushed aluminum has no protection on it at all; it would be a fingerprint magnet and tarnish over time (which could look cool).
 
May 6, 2024 at 8:23 AM Post #2,394 of 2,397
Wouldn't you want some sort of anodizing on it? Straight brushed aluminum has no protection on it at all; it would be a fingerprint magnet and tarnish over time (which could look cool).

Dave normally offers anodization, which is done by a shop local to him. It's unusual to just do brushed aluminum, but I don't know what was discussed. Regardless, all of the chassis panels have to be grounded, and obviously the signal and safety earth connections have to be grounded to the chassis. Not doing so is a safety issue.
 
May 9, 2024 at 1:47 PM Post #2,396 of 2,397
I would like to be able to use the Aegis, also as a preamplifier.

I think that if I add RCA outputs, connecting them simultaneously to the Elma switch output (where the Switchcraft is also connected), I will solve the problem (when I use it as a preamp, I turn off the headphones).

My questions are regarding this connection:
1) at which end of these connections do I connect the ground (RCA out or next to the Elma switch)?
2) where is the best place to connect the ground?

Thank you very much in advance.
 
May 9, 2024 at 7:47 PM Post #2,397 of 2,397
I would like to be able to use the Aegis, also as a preamplifier.

I think that if I add RCA outputs, connecting them simultaneously to the Elma switch output (where the Switchcraft is also connected), I will solve the problem (when I use it as a preamp, I turn off the headphones).

My questions are regarding this connection:
1) at which end of these connections do I connect the ground (RCA out or next to the Elma switch)?
2) where is the best place to connect the ground?

Thank you very much in advance.

Do you mean that both connections will be always on, meaning the preamp out and headphone out connected in parallel without a switch? That should be fine, obviously you would not want to keep the headphone plugged in when using it as a preamp. The RCA outs would be connected to the ELMA switch board, same connections as the TRS, red to signal, black to ground. The ground connection is made off the TRS ground pin to the PCB. If the RCA grounds are connected to the ELMA switch, they will be grounded via the same path. Full disclosure I have not tried this, on paper it should work fine, but obligatory YMMV.
 

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