3 mm LED behind knob:
http://www.diyaudio.com/forums/showthread.php?postid=1560562#post1560562
simply drilled a hole and glued it in
http://www.diyaudio.com/forums/showthread.php?postid=1560562#post1560562
simply drilled a hole and glued it in
Tonight I rewired the preamplifier, untwisting and thus shortening the wires to the pots, and thereafter the clarity returned. Thanks for all those who helped.
As to the backlit knob, my knobs are recessed about 1/4 of an inch, so I'm wondering if the backlit light would escape. At this point I'll just enjoy the music.
As to the backlit knob, my knobs are recessed about 1/4 of an inch, so I'm wondering if the backlit light would escape. At this point I'll just enjoy the music.
To beat a dead horse....
I've had a couple of requests for the 48VDC power supplies and I "think" I have it down to an art.
If you are interested in a couple of the power supplies you can go to USPS and purchase a shipping label < TO and FROM yourself> for the small flat rate box. It costs about $4.80 in the US and it was ~$12.50 to Malaysia. Email the label to me and I will print it and tape it to the box and drop the pair of power supplies in the mail.
That's it. You pay for the shipping label at the US post office web site and email it to me and you get two brand new free pwr supplies and a standard six foot IEC power cable. <The cable fills the extra space and makes for secure packing in the box>
Here is the link to the USPS:
https://sss-web.usps.com/cns/landing.do
Once again, I "only" get a clean conscious from this. I can't see throwing these in a land fill.
I've had a couple of requests for the 48VDC power supplies and I "think" I have it down to an art.
If you are interested in a couple of the power supplies you can go to USPS and purchase a shipping label < TO and FROM yourself> for the small flat rate box. It costs about $4.80 in the US and it was ~$12.50 to Malaysia. Email the label to me and I will print it and tape it to the box and drop the pair of power supplies in the mail.
That's it. You pay for the shipping label at the US post office web site and email it to me and you get two brand new free pwr supplies and a standard six foot IEC power cable. <The cable fills the extra space and makes for secure packing in the box>
Here is the link to the USPS:
https://sss-web.usps.com/cns/landing.do
Once again, I "only" get a clean conscious from this. I can't see throwing these in a land fill.
Re: Re: To beat a dead horse....
Create one and email it to me. I think I suggested half a pound of weight earlier to someone else but it is a flat rate box so it doesn't matter.
Yes sir... 48VDC.. But these are FREE and a simple voltage divider will fix the low current voltage issue.
Again I am trying to keep these OUT of a landfill.
EDIT: sorry for the delay, I was in TX hill country doing three twisted sisters...
Hwy 335, 336 and 337.. They just don't make them like that in Lousy Ann A. Curves AND elevation!
http://www.openroadjourney.com/loadroute.asp?rid=705
http://www.barrypopik.com/index.php...d_sisters_or_100_mile_loop_rr335_rr336_rr337/
AndrewT said:
Create one and email it to me. I think I suggested half a pound of weight earlier to someone else but it is a flat rate box so it doesn't matter.
Nelson Pass said:48V supplies?
The nominal spec for B1 is 18 to 25V. You can get the switchers from
Digikey or Marlin P Jones.
Yes sir... 48VDC.. But these are FREE and a simple voltage divider will fix the low current voltage issue.
Again I am trying to keep these OUT of a landfill.
EDIT: sorry for the delay, I was in TX hill country doing three twisted sisters...
Hwy 335, 336 and 337.. They just don't make them like that in Lousy Ann A. Curves AND elevation!http://www.openroadjourney.com/loadroute.asp?rid=705
http://www.barrypopik.com/index.php...d_sisters_or_100_mile_loop_rr335_rr336_rr337/
Re: Re: Re: To beat a dead horse....
You did the 100 mile loop on bicycle or motorcycle? I love rides with some elevation.
troystg said:
...
EDIT: sorry for the delay, I was in TX hill country doing three twisted sisters...
http://www.openroadjourney.com/loadroute.asp?rid=705
http://www.barrypopik.com/index.php...d_sisters_or_100_mile_loop_rr335_rr336_rr337/
You did the 100 mile loop on bicycle or motorcycle? I love rides with some elevation.
DC Offset
I've just completed wiring up the B1 on a vector board. Phew - the layout took a fair bit of planning, but it all fit correctly.
Modifications over "stock": I'm using a 50K stereo log taper pot. Before the power supply I've put a fairly standard Sulzer regulator set to produce 20.1V (after a few minutes settling time the regulator output arrives at a very steady 20.5V). I've also placed a 2.5K resistor across the output of the regulator to ground so that it draws a constant 8mA both to help testing (the resistor is a convenient place to place multimeter leads) and to bring the overall current draw of the circuit up since my AC adapter is 24V at 400mA and 30V unloaded. I believe the AC adapter is a regulated switcher.
The problem: when I turn it on, the output sees an immediate 150mV of DC offset. It drops to about 80mV in 10 sec or so, and then shoots up to around 350mV before dropping to something like 0.2mV over the course of a few minutes.
Our friend Burner noted a similar problem earlier in this thread, and I note two similarities with my build: he too used his own layout on a perf board (vector board is similar), and he too used a fancy voltage regulator. Might either of these things point to a problem? Has anyone else seen a DC offset? Is this amount of DC offset troublesome? My power amp is currently a Zen V4 which has big ol' caps in the signal path which probably will take care of the DC, but I'm planning on upgrading to an F5 when I find the time...
Burner found that his 10uF output cap made a large difference on both the amount of DC offset and the time it took to settle - I'm using 10uF regular Mundorf MCaps (MKP).
thanks in advance,
-j
I've just completed wiring up the B1 on a vector board. Phew - the layout took a fair bit of planning, but it all fit correctly.
Modifications over "stock": I'm using a 50K stereo log taper pot. Before the power supply I've put a fairly standard Sulzer regulator set to produce 20.1V (after a few minutes settling time the regulator output arrives at a very steady 20.5V). I've also placed a 2.5K resistor across the output of the regulator to ground so that it draws a constant 8mA both to help testing (the resistor is a convenient place to place multimeter leads) and to bring the overall current draw of the circuit up since my AC adapter is 24V at 400mA and 30V unloaded. I believe the AC adapter is a regulated switcher.
The problem: when I turn it on, the output sees an immediate 150mV of DC offset. It drops to about 80mV in 10 sec or so, and then shoots up to around 350mV before dropping to something like 0.2mV over the course of a few minutes.
Our friend Burner noted a similar problem earlier in this thread, and I note two similarities with my build: he too used his own layout on a perf board (vector board is similar), and he too used a fancy voltage regulator. Might either of these things point to a problem? Has anyone else seen a DC offset? Is this amount of DC offset troublesome? My power amp is currently a Zen V4 which has big ol' caps in the signal path which probably will take care of the DC, but I'm planning on upgrading to an F5 when I find the time...
Burner found that his 10uF output cap made a large difference on both the amount of DC offset and the time it took to settle - I'm using 10uF regular Mundorf MCaps (MKP).
thanks in advance,
-j
Re: DC Offset
Any pictures of the layout? Sorry if you mentioned it earlier, but did you build the original Pass design with the single power supply?
About the symmetrical power supply, there is something I'm wondering about: I read the whole thread (spending the last few nights ;-) and I'm still missing something like a statement of Nelson that this Zen-Mod version is really an alternative to his original design. I mean, is it a waterproof design? Is it correct to leave the 1,0uF caps out with the dual supply, or is it more likely a possibility?
If one plans to build everything on his own, the symmetrical ps would be as easy to build as the single ps, so I'm really wondering which one is the 'safer' and more convincing one, also in concern to the DC offset problem!
And one more thing: What about a dual linear supply with a RC-stage to achieve proper supply voltage? E.g., transformer (2x9V sec.), rectifier, smoothing cap, and then (from the Zen-Mod version) R1 & R2 together with C1 & C2 as RC-stages, choosing a value for the R's so that voltage is around +-9V? Is the B1 in general sensitive to slightly differing supply voltage (because of some slight drifts of main voltage from the AC power outlet)?
Thanks for your advices!
martin
Any pictures of the layout? Sorry if you mentioned it earlier, but did you build the original Pass design with the single power supply?
About the symmetrical power supply, there is something I'm wondering about: I read the whole thread (spending the last few nights ;-) and I'm still missing something like a statement of Nelson that this Zen-Mod version is really an alternative to his original design. I mean, is it a waterproof design? Is it correct to leave the 1,0uF caps out with the dual supply, or is it more likely a possibility?
If one plans to build everything on his own, the symmetrical ps would be as easy to build as the single ps, so I'm really wondering which one is the 'safer' and more convincing one, also in concern to the DC offset problem!
And one more thing: What about a dual linear supply with a RC-stage to achieve proper supply voltage? E.g., transformer (2x9V sec.), rectifier, smoothing cap, and then (from the Zen-Mod version) R1 & R2 together with C1 & C2 as RC-stages, choosing a value for the R's so that voltage is around +-9V? Is the B1 in general sensitive to slightly differing supply voltage (because of some slight drifts of main voltage from the AC power outlet)?
Thanks for your advices!
martin
martinbls said:
I'll get some pictures up tomorrow - not much can go wrong in the B1 however. It was indeed the standard single supply B1.
With regards to a statement from Mr. Pass about the dual supply version: Papa Pass tends to let his children argue amongst themselves over minor variations to his designs. ;-) I'm not positive about Choky's version, but Salas' has been built by some and would seem to be working (though I certainly couldn't see anything wrong with Choky's version either).
-j