Very nice build, Fred! Looks like you drilled your own front panel to accommodate the locking headphone jack, but left the stock rear panel in place. And the preamp output RCA jacks are mounted in position, even though you don't have flywires connecting them to the circuit board. Very pretty.
yes indeed - I did need another back panel and drill it with only 1 pair RCA as I'm not using the two of them. Very happy with sound Mark! Great design!
How have I never known about Octopart?? Also, totally forgot to check Newark. Thanks! I think I'm up to 5 different shopping carts for this... time to see if I can consolidate.
help with part substituions
I am putting together my parts list for the Noir pcb's I received as a gift last week.
I prefer ordering from digikey, and have been able to sub most of the parts that were not available.
There are still a couple parts I need to figure out how to substitute.
Can someone just give me a good idea of what to sub for ...
D25, D75: E-153 Current Regulator Diode
LED: Lite-On Led Is there anything special about this, or will any 3mm led do? Digikey says it is in stock, but "A separate quote is required for this product." Not sure what that means.
Lastly, has anyone substituted any of the metal film resistors for carbon comp ones? I need to study the schematic a bit more to understand which ones are in the audio path. (p.s. I am a bit new to transistor based amps)
Thanks for any help.
edit: ugh, looks like i spoke too soo, need to find replacements for Q21, Q71, Q22, Q72, D1 too.
I am putting together my parts list for the Noir pcb's I received as a gift last week.
I prefer ordering from digikey, and have been able to sub most of the parts that were not available.
There are still a couple parts I need to figure out how to substitute.
Can someone just give me a good idea of what to sub for ...
D25, D75: E-153 Current Regulator Diode
LED: Lite-On Led Is there anything special about this, or will any 3mm led do? Digikey says it is in stock, but "A separate quote is required for this product." Not sure what that means.
Lastly, has anyone substituted any of the metal film resistors for carbon comp ones? I need to study the schematic a bit more to understand which ones are in the audio path. (p.s. I am a bit new to transistor based amps)
Thanks for any help.
edit: ugh, looks like i spoke too soo, need to find replacements for Q21, Q71, Q22, Q72, D1 too.
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If the Lite-On is in the bias circuit I would not sub it. I have a couple left over, I think, so chime if needed.
The Semitec E-153 current regulator diode is in stock at Mouser.com (355 pieces on the shelf). Regrettably, Semitec does not distribute thru DigiKey. Double check using Octopart:
link
It's a good idea to use Octopart when searching for components; it will tell you how many pieces are in stock at each distributor.
The important characteristics of the LTL-14CDJN LED are: (1) it's BIDIRECTIONAL; (2) it's in a 3mm "T1" package. Digikey has 3698 pieces of them on the shelf. If you're hoping to save money, Digikey offers the 1125-1183-ND bidirectional LED, for ten cents less.
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link
It's a good idea to use Octopart when searching for components; it will tell you how many pieces are in stock at each distributor.
The important characteristics of the LTL-14CDJN LED are: (1) it's BIDIRECTIONAL; (2) it's in a 3mm "T1" package. Digikey has 3698 pieces of them on the shelf. If you're hoping to save money, Digikey offers the 1125-1183-ND bidirectional LED, for ten cents less.
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I sometimes use Octopart for car parts as well. Newark/Farnell seem to be the only place for the BC516 for now:
https://www.newark.com/search?st=bc516
I saw that Mouser should be getting some in September.
I ended up getting everything, except BC516, via ordering across 2 retailers (digikey, mouser). I backordered the BC516 via the same order from Mouser, as the September supply was listed. If I find that part else where before then, I'll post back. I did see it available from one place on oceopart, but was not familiar with the retailer.
Okay, dumb question. Which resistors needed t I be changed/connected differently to go to a negative ground?
I got a Private Message containing the inquiry quoted below. Because I believe the Forum is a much better vehicle for communication with the entire diyAudio membership, I've copied the question here. Anyone and everyone, please accept my invitation to share your insight, thoughts, studied opinions, and casual remarks.
click on the image to see it full size and undistorted:
click on the image to see it full size and undistorted:
Lovely build, csdawson, congratulations! Beautiful job cleaning up flux residue and gunk from the PCB, it's pristine.
You must have a very high brightness LED to need extra series resistors installed in both flywire holes E and F.
You must have a very high brightness LED to need extra series resistors installed in both flywire holes E and F.
Haha, yeah. I didn't look closely enough at the intensity number and it was a factor of 100 higher than the speced LED. I like my LEDs quite dim, so I just kept adding resistors. I think I ended up with nearly 200k in there.
Okay folks, question - I was thinking about adding an output buffer (plus summing for 2.1 out) to the amp immediately before the RCA out. Using OPA2134s and a DPB09B-15.
Initial L+R input to the bottom OPA as non-inverting. Then using top OPA as summing and subsequent re-inversion. The DPB09B-15 is a dual 15V isolated PS (300mA/rail).
Anybody see any immediate issues with doing this? I am likely still missing a few caps for smoothing the DPBs output.
Initial L+R input to the bottom OPA as non-inverting. Then using top OPA as summing and subsequent re-inversion. The DPB09B-15 is a dual 15V isolated PS (300mA/rail).
Anybody see any immediate issues with doing this? I am likely still missing a few caps for smoothing the DPBs output.
Attachments
Wow, those dual opamp "symbols" make reading the schematic quite a challenge.
SubOut = (+1) * CONSTANT * (Lin + Rin)
What value of "CONSTANT" are you hoping to achieve? I think you may want to change the 500 ohm resistor values to get the CONSTANT you desire (?)
SubOut = (+1) * CONSTANT * (Lin + Rin)
What value of "CONSTANT" are you hoping to achieve? I think you may want to change the 500 ohm resistor values to get the CONSTANT you desire (?)
Yeah...sorry about that. I blame KiCad that I've been playing with. By "constant" do you mean gain? If so, I was shooting for unity gain to start with.
I think if you work out the transfer function of the circuit in post #316, it will tell you that in the expression
SubOut = (+1) * CONSTANT * (Lin + Rin)
the number "CONSTANT" is not equal to 1.0. {I could be wrong}
And, oh by the way, I doubt that you actually want CONSTANT=1.0 . Think about a monophonic input having Lin=Rin. Oopsie!
SubOut = (+1) * CONSTANT * (Lin + Rin)
the number "CONSTANT" is not equal to 1.0. {I could be wrong}
And, oh by the way, I doubt that you actually want CONSTANT=1.0 . Think about a monophonic input having Lin=Rin. Oopsie!
looks amazing! Did you change any parts from the stock BOM? if so, could you share what you changed and why? I'm looking to experiment with mine to change the sound, and/or build another one with premium parts - and am looking for suggestions on the best possible parts to fit!