Sheldon...never ever ever!!!...do you have a male connector on the chassis...if the unit was powered up and someone being sloppy trying to reach behind the unit would short it out....same principle as an extenstion cord..LOL
JOE DIRT® said:Sheldon...never ever ever!!!...do you have a male connector on the chassis...if the unit was powered up and someone being sloppy trying to reach behind the unit would short it out....same principle as an extenstion cord..LOL
Right, female connectors for signal out, male connectors for signal in. that makes sense but it appears that audio pre-amps don't follow that convention?
Sheldon
Re: APOX-1 C++ program available
Thank you so much for giving us that program as source! I am so tired of getting ******* wintel *.exe files. then I have to boot up the PeeCee and ftp it.
You're still using MFC nastiness though, so you aren't out of the woods yet. 🙂 I had to pull out stdafx.h and use stdlib.h and stdio.h
But I popped open an xterm and did:
>c++ res_test.cpp
>a.out
and I had joy...
A quick trip into gnuplot and I'm looking at a plot in less than a minute.
Sheldon
dipchip said:
Thank you so much for giving us that program as source! I am so tired of getting ******* wintel *.exe files. then I have to boot up the PeeCee and ftp it.
You're still using MFC nastiness though, so you aren't out of the woods yet. 🙂 I had to pull out stdafx.h and use stdlib.h and stdio.h
But I popped open an xterm and did:
>c++ res_test.cpp
>a.out
and I had joy...
A quick trip into gnuplot and I'm looking at a plot in less than a minute.
Sheldon
caution
Hi Sheldon,
NEVER, NEVER use male for input !!!
1) Standard is female -> input
male -> output
Reason: Mixing console input sensitivity can be -60dBU or more!
Now if you touch an open input with your fingers, you blow your
zillion kilowatt PA-system! (and some listeners ears not to
mention the sum you have to pay to those listeners at a public
show)
BTW why change a proven industry standard?
Uli
stokessd said:
Hi Sheldon,
NEVER, NEVER use male for input !!!
1) Standard is female -> input
male -> output
Reason: Mixing console input sensitivity can be -60dBU or more!
Now if you touch an open input with your fingers, you blow your
zillion kilowatt PA-system! (and some listeners ears not to
mention the sum you have to pay to those listeners at a public
show)
BTW why change a proven industry standard?
Uli
Hugh,
Thanks for all of the complements!
There are 14 DPST relays on the APOX-1
(You can see the board layout here )
I really can't wait to test the APOX-1 to see how it actually performs. I may have to do tricks to prevent any clicking and popping noises between settings. But if it works, it should be a very smooth volume control.
APOX-3 people,
There will be a slight delay on the APOX-3 prototype boards.
Dale decided to add a bunch of new features for the APOX-3 board. We will now have an onboard headphone amplifier that the user can switch in or out. This allows the people that keep asking us about an extra headphone ouput to sleep easy tonight.
I think I am also going to opto-isolate the micro from the PGA2310 to try to eliminate digital noise from entering the picture.
-Craig
Thanks for all of the complements!
There are 14 DPST relays on the APOX-1
(You can see the board layout here )
I really can't wait to test the APOX-1 to see how it actually performs. I may have to do tricks to prevent any clicking and popping noises between settings. But if it works, it should be a very smooth volume control.
APOX-3 people,
There will be a slight delay on the APOX-3 prototype boards.
Dale decided to add a bunch of new features for the APOX-3 board. We will now have an onboard headphone amplifier that the user can switch in or out. This allows the people that keep asking us about an extra headphone ouput to sleep easy tonight.
I think I am also going to opto-isolate the micro from the PGA2310 to try to eliminate digital noise from entering the picture.
-Craig
Sheldon,
Are you a Linux user or do you use the Gnu Cygwin tools inside of windows.
I miss using the Unix/QNX/Cygwin tools. So much easier to do simple tasks than the whole Windows tool suites.
Dale
Are you a Linux user or do you use the Gnu Cygwin tools inside of windows.
I miss using the Unix/QNX/Cygwin tools. So much easier to do simple tasks than the whole Windows tool suites.
Dale
headphoneouts...
will you be using a pair of buf634 for the phoneouts - powered by some heavy duty regulators a la didden/jung...??? (dual mono) 😉
will you be using a pair of buf634 for the phoneouts - powered by some heavy duty regulators a la didden/jung...??? (dual mono) 😉
Hi Tbla,
I orginally thought about the Jung regs...
What about some good LDO regulators?
We are doing dual mono and using the BUF634.
Dale
I orginally thought about the Jung regs...
What about some good LDO regulators?
We are doing dual mono and using the BUF634.
Dale
harvardian said:
I'm a bastardized mix of alliances. I use linux (redhat) at work on one project and I'm probably most productive there in terms of ease and speed of data analysis. On my other project I'm using Win2K and doing labview development. At home I use Win2K for certain specific tasks, like speaker measurement. I do some light development on it using MS's developer studio and compaq visual fortran.
But I also have a Macintosh running OS X. the very cool part about OS X is that I have a very refined GUI for those times when I want that, but OS X is sitting on top of a moisturized FreeBSD so I have all my unix tools and command line goodies. In fact it's such a nice mix, that I have X11 running concurrently (rootless) with the Mac Aqua GUI. X11 apps coexist nicely, it's the best of all possible worlds. But saying that I use a mac makes me look like a bit of a weenie.
Sheldon
apox-3 design ideas
tbla,
I also found out after reading the PGA2310 datasheet
that they really want the inputs to be driven by a low impedance
source. So I have decided to buffer the inputs using a OPA2134
in a voltage follower setup.
This may or may not help people! But I don't think it will hurt either.
I will then take the PGA2310's VOUTL and VOUTR signals
(actually V+ and V- in my case)
and feed this into a diff amp. made with a OPA134
The output of the OPA134 will then feed into the highcurrent driver BUF634.
The BUF634 would then of course drive your headphones.
Dale and I were also thinking of completely seperating the
power supplies for the two PGA2310 chips, and opto-isolating
both of them from the microcontroller.
The Walter Jung regulators would certainly be nice, but the number of components is already starting to get pretty high
for a DIY kit.
I think some high quality LDO linear regulators for each chip would be sufficient.
So there might be 6 voltage regulators on each board.
A +15,-15,+5V regulator for each PGA2310 chip.
Does anyone have any comments on the above scheme.
Thanks,
Craig Beiferman
tbla,
I also found out after reading the PGA2310 datasheet
that they really want the inputs to be driven by a low impedance
source. So I have decided to buffer the inputs using a OPA2134
in a voltage follower setup.
This may or may not help people! But I don't think it will hurt either.
I will then take the PGA2310's VOUTL and VOUTR signals
(actually V+ and V- in my case)
and feed this into a diff amp. made with a OPA134
The output of the OPA134 will then feed into the highcurrent driver BUF634.
The BUF634 would then of course drive your headphones.
Dale and I were also thinking of completely seperating the
power supplies for the two PGA2310 chips, and opto-isolating
both of them from the microcontroller.
The Walter Jung regulators would certainly be nice, but the number of components is already starting to get pretty high
for a DIY kit.
I think some high quality LDO linear regulators for each chip would be sufficient.
So there might be 6 voltage regulators on each board.
A +15,-15,+5V regulator for each PGA2310 chip.
Does anyone have any comments on the above scheme.
Thanks,
Craig Beiferman
OPA627
The OPA627 is $15.25 for a single op-amp.
I would need 6 on a board. $91.50 total.
vs. $8.82 for two OPA2134 and 2 OPA134's
Do you still want it?
-Craig
The OPA627 is $15.25 for a single op-amp.
I would need 6 on a board. $91.50 total.
vs. $8.82 for two OPA2134 and 2 OPA134's
Do you still want it?
-Craig
For those that like to have the best opamps, I have convinced Craig to use single opamps. The following chips have the same (or nearly equiv) pinouts.
All support +/-15V, all are unity gain stable, low noise, high BW.
We will have lots of local decoupling available.
OPA604
OPA134
LT1028
OPA627
AD825 (with adapter)
AD797
LM6171
If you limit to +/- 13V, one could also use a AD8610 with an adapter.
The PGA2310 should work OK at +/-13V
Etc...
Dale
We will supply a "house" brand (Best price/performance), but you can substitute others.
All support +/-15V, all are unity gain stable, low noise, high BW.
We will have lots of local decoupling available.
OPA604
OPA134
LT1028
OPA627
AD825 (with adapter)
AD797
LM6171
If you limit to +/- 13V, one could also use a AD8610 with an adapter.
The PGA2310 should work OK at +/-13V
Etc...
Dale
We will supply a "house" brand (Best price/performance), but you can substitute others.
very nice - i'm ready to place an order...!!! .....and yes, if you put jungregs all over, it would be allmost too much...!🙂
Would people have a major objection to the LT1085/LT1033 regulators with Fred's colorful LEDs? 
We will probably have a power supply board to house the diodes, filter caps, and a pre-regulator. The final regulation will be on-board.
Best Regards,
Dale
We will probably have a power supply board to house the diodes, filter caps, and a pre-regulator. The final regulation will be on-board.
Best Regards,
Dale
harvardian said:
😕
But only dual op-amps have a common pinout. Singles and quads are all over the map.
Sheldon
Hi Sheldon,
I could have been hasty, but double check the ones that I posted. Besides for some offset trimming, all share:
+, -, V-, V+, and output. Some have trims or other adjustments on pins 1, and 5. Most have NC on 8.
Best Regards,
Dale
I could have been hasty, but double check the ones that I posted. Besides for some offset trimming, all share:
+, -, V-, V+, and output. Some have trims or other adjustments on pins 1, and 5. Most have NC on 8.
Best Regards,
Dale
harvardian said:
Maybe I was hasty, but I recall being screwed in the past with single op-amps. I did a quick skim through an old burr brown data book and all the single op-amps I flipped to had the same pin-outs. I'm pretty sure there are different pinouts though.
Sheldon
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