Petter said:
Petter,
I didn't mean to make fun of anybody. I had a genuine interest in knowing what motivated that choice. I purposedly disregarded all the post regarding the Apox1 because I prefer the classic constant impedance design Apox2. Thanks for summarizing a long series of posts for me and sorry if it appeared I was making fun of you.
grataku said:
yes it cirtainly can,
A long time ago, i built a pre-amp with relays to switch the sources, i ommitted the diode because they where built in to the relay driver. The relays were a cable lenght away from the driver (2003 or 2803 i think) and i had all sorts of trouble when swithcing source, pops in the sound and cmos jumping states. Modded some diodes on the pins of the relay, and problem solved !
😎
pops on APOX-1
Dale and I observed the pops on an Oscilloscope yesterday.
I am almost certain that the popping noise was occuring
primarily due to the order that I was switching relays. And possibly some relay bounce.
I was switching them in such a way that the volume could have temporarily risen, producing a small jump in the output.
With my new scheme, as previously mentioned, I think I will eliminate the pops.
I have one other tidbit of information. Dale thought that his transformers may be a higher A.C. voltage than he expected. (Which was causing his +/- 60V regulators to excessively heat up.) If this is the case, I won't be too suprised if the lowest
impedance setting on the APOX-1 is drawing too much current from Dales X-BOSOZ. therefore causing the rails of his voltage regulators to fluctuate at the A.C. line frequency.
-Craig Beiferman
Dale and I observed the pops on an Oscilloscope yesterday.
I am almost certain that the popping noise was occuring
primarily due to the order that I was switching relays. And possibly some relay bounce.
I was switching them in such a way that the volume could have temporarily risen, producing a small jump in the output.
With my new scheme, as previously mentioned, I think I will eliminate the pops.
I have one other tidbit of information. Dale thought that his transformers may be a higher A.C. voltage than he expected. (Which was causing his +/- 60V regulators to excessively heat up.) If this is the case, I won't be too suprised if the lowest
impedance setting on the APOX-1 is drawing too much current from Dales X-BOSOZ. therefore causing the rails of his voltage regulators to fluctuate at the A.C. line frequency.
-Craig Beiferman
Dale, oppty to improve your preamp PSU
Dale,
If this is the case (too much voltage at transformers), consider adding an LCRC or just RC network ahead of the regulator. While doing so, consider turning the transformer so the leadouts face away from the circuitry (unless you have a magnetic enclosure in which case they migth go anywhere).
I have done this with my Pearl where I have RC --> LC(diff mode with enough R to serve as R as well) --> LC(common mode -- you can get really big CM inductors, I had wound a 150mH unit which was much smaller than a quarter but cannot remember if I used it or ended up with a retail unit) --> RC network which drops about 20 volts or so 🙂 before I get into the regulators on the Pearl. Of course I split the value so that both phases see it. In order to protect regulators etc., one can use a zener stack to ensure voltage never goes above a predetermined level (which should be several volts higher than the level required at minimal load).
Petter
Dale,
If this is the case (too much voltage at transformers), consider adding an LCRC or just RC network ahead of the regulator. While doing so, consider turning the transformer so the leadouts face away from the circuitry (unless you have a magnetic enclosure in which case they migth go anywhere).
I have done this with my Pearl where I have RC --> LC(diff mode with enough R to serve as R as well) --> LC(common mode -- you can get really big CM inductors, I had wound a 150mH unit which was much smaller than a quarter but cannot remember if I used it or ended up with a retail unit) --> RC network which drops about 20 volts or so 🙂 before I get into the regulators on the Pearl. Of course I split the value so that both phases see it. In order to protect regulators etc., one can use a zener stack to ensure voltage never goes above a predetermined level (which should be several volts higher than the level required at minimal load).
Petter
Gold plating
I believe gold directly on copper is a problem and that the preferred method is to nickel plate first. Nickel is ferromagnetic. Silver might be better, though 🙂
However, gold plated boards do look nice, check out this preamp on this page (bottom right for internal view) http://www.chapteraudio.co.uk
If you are interested in discussion of magnetism where the ferro type is the most severe (and did you know aluminium is dia-magnetic?), go here http://www.diyaudio.com/forums/show...erpage=15&highlight=paramagnetic&pagenumber=2
If you are interested in the gold plating thread, it is here http://www.diyaudio.com/forums/showthread.php?threadid=6311&highlight=gold+plating
Petter
I believe gold directly on copper is a problem and that the preferred method is to nickel plate first. Nickel is ferromagnetic. Silver might be better, though 🙂
However, gold plated boards do look nice, check out this preamp on this page (bottom right for internal view) http://www.chapteraudio.co.uk
If you are interested in discussion of magnetism where the ferro type is the most severe (and did you know aluminium is dia-magnetic?), go here http://www.diyaudio.com/forums/show...erpage=15&highlight=paramagnetic&pagenumber=2
If you are interested in the gold plating thread, it is here http://www.diyaudio.com/forums/showthread.php?threadid=6311&highlight=gold+plating
Petter
Has anyone considered the effect that the soldermask has on the sound. I believe that it is more important than the choice of teflon or fiberglass.
Regards,
Jam
Regards,
Jam
Jam,
this was a perfectly legit thread with real issues discussed until now. 😉
Peter, what's wrong with plating teflon? It can be done, it probably is very expensive.
this was a perfectly legit thread with real issues discussed until now. 😉
Peter, what's wrong with plating teflon? It can be done, it probably is very expensive.
Soldermask Blues!
Grataku,
I was wanting to build the input and volume boards without the soldermask.
Since we are attempting to build the ultimare preamp I think all avenues should be investigated. The only reason I bring this up is the fact that I have tried this experiment and some soldermask material can hurt the sound.
Maybe a solution is to only soldermask above the traces?
Regards,
Jam
P.S. If anyone has worked with teflon boards know how much of a problem they can be to work with.......
Grataku,
I was wanting to build the input and volume boards without the soldermask.
Since we are attempting to build the ultimare preamp I think all avenues should be investigated. The only reason I bring this up is the fact that I have tried this experiment and some soldermask material can hurt the sound.
Maybe a solution is to only soldermask above the traces?
Regards,
Jam
P.S. If anyone has worked with teflon boards know how much of a problem they can be to work with.......
I remember that Madrigal in ML line was originally using no mask over traces, but looking now at the reference preamp, there is solder mask.
Jam,
having air between the traces instead of solder mask dielectric maybe better for sound I don't know. Quite frankly I never did a comparison between two identical pieces of equipment differing only by the presence or absence of solder mask and I think I probably never will.
having air between the traces instead of solder mask dielectric maybe better for sound I don't know. Quite frankly I never did a comparison between two identical pieces of equipment differing only by the presence or absence of solder mask and I think I probably never will.
There is nothing wrong with plating teflon except plating typically does not stick very well ("teflon is very slippery"). I was referring to plating Cu.
If you refer to using gold as traces that would be cool, but I am unsure about the best way to remove the stuff not needed.
Petter
If you refer to using gold as traces that would be cool, but I am unsure about the best way to remove the stuff not needed.
Petter
APOX-1 Hum update
I looked at the header file my program generated for Dales
resistor values.
At setting 170 - moderate hum has setting (0,2)
At setting 187 - high hum has setting (0,1)
So Petter's assesment that my program should shoot for the lowest input impedance near the highest volumes is correct.
I'll try to modify my program today to avoid this high impedance situation. I'll also add the popping reduction technique.
Here is a snippet of the header file/
-- SNIP --
{2 , 38}, // Volume Setting 164 = -22.214026 dB
{3 , 56}, // Volume Setting 165 = -21.972975 dB
{3 , 54}, // Volume Setting 166 = -21.709510 dB
{3 , 53}, // Volume Setting 167 = -21.562437 dB
{3 , 51}, // Volume Setting 168 = -21.260842 dB
{1 , 19}, // Volume Setting 169 = -21.060094 dB
{0 , 2}, // Volume Setting 170 = -20.828975 dB
{3 , 47}, // Volume Setting 171 = -20.585297 dB
{2 , 30}, // Volume Setting 172 = -20.293540 dB
{3 , 44}, // Volume Setting 173 = -20.075310 dB
{3 , 43}, // Volume Setting 174 = -19.896322 dB
{3 , 42}, // Volume Setting 175 = -19.716216 dB
{2 , 27}, // Volume Setting 176 = -19.480795 dB
{2 , 26}, // Volume Setting 177 = -19.194250 dB
{3 , 38}, // Volume Setting 178 = -18.984281 dB
{3 , 37}, // Volume Setting 179 = -18.782369 dB
{3 , 36}, // Volume Setting 180 = -18.577326 dB
{2 , 23}, // Volume Setting 181 = -18.319274 dB
{2 , 22}, // Volume Setting 182 = -17.990947 dB
{3 , 32}, // Volume Setting 183 = -17.699832 dB
{1 , 12}, // Volume Setting 184 = -17.487811 dB
{2 , 20}, // Volume Setting 185 = -17.291613 dB
{3 , 30}, // Volume Setting 186 = -17.144744 dB
{0 , 1}, // Volume Setting 187 = -16.853514 dB
{3 , 28}, // Volume Setting 188 = -16.638951 dB
{3 , 27}, // Volume Setting 189 = -16.371749 dB
{1 , 10}, // Volume Setting 190 = -16.168825 dB
-- SNIP --
-Craig
I looked at the header file my program generated for Dales
resistor values.
At setting 170 - moderate hum has setting (0,2)
At setting 187 - high hum has setting (0,1)
So Petter's assesment that my program should shoot for the lowest input impedance near the highest volumes is correct.
I'll try to modify my program today to avoid this high impedance situation. I'll also add the popping reduction technique.
Here is a snippet of the header file/
-- SNIP --
{2 , 38}, // Volume Setting 164 = -22.214026 dB
{3 , 56}, // Volume Setting 165 = -21.972975 dB
{3 , 54}, // Volume Setting 166 = -21.709510 dB
{3 , 53}, // Volume Setting 167 = -21.562437 dB
{3 , 51}, // Volume Setting 168 = -21.260842 dB
{1 , 19}, // Volume Setting 169 = -21.060094 dB
{0 , 2}, // Volume Setting 170 = -20.828975 dB
{3 , 47}, // Volume Setting 171 = -20.585297 dB
{2 , 30}, // Volume Setting 172 = -20.293540 dB
{3 , 44}, // Volume Setting 173 = -20.075310 dB
{3 , 43}, // Volume Setting 174 = -19.896322 dB
{3 , 42}, // Volume Setting 175 = -19.716216 dB
{2 , 27}, // Volume Setting 176 = -19.480795 dB
{2 , 26}, // Volume Setting 177 = -19.194250 dB
{3 , 38}, // Volume Setting 178 = -18.984281 dB
{3 , 37}, // Volume Setting 179 = -18.782369 dB
{3 , 36}, // Volume Setting 180 = -18.577326 dB
{2 , 23}, // Volume Setting 181 = -18.319274 dB
{2 , 22}, // Volume Setting 182 = -17.990947 dB
{3 , 32}, // Volume Setting 183 = -17.699832 dB
{1 , 12}, // Volume Setting 184 = -17.487811 dB
{2 , 20}, // Volume Setting 185 = -17.291613 dB
{3 , 30}, // Volume Setting 186 = -17.144744 dB
{0 , 1}, // Volume Setting 187 = -16.853514 dB
{3 , 28}, // Volume Setting 188 = -16.638951 dB
{3 , 27}, // Volume Setting 189 = -16.371749 dB
{1 , 10}, // Volume Setting 190 = -16.168825 dB
-- SNIP --
-Craig
Plating of PCBs are usually done prior to etching. Plating an etched board will require that all traces are connected....
Also, gold does not etch very well at all....
There is a silver dip coating on the market, which work by autocathalysis..
Gives an appx 3-5 microns deposit...
I usually tin plate my boards in the same way...
Also, gold does not etch very well at all....
There is a silver dip coating on the market, which work by autocathalysis..
Gives an appx 3-5 microns deposit...
I usually tin plate my boards in the same way...
While the DIPCHIP engineering team is tackling important issues, I have been focusing on more mundane issues like designing my own enclosure for this thing.
Since we are lucky enough to have the channel split into two, I thought to take advantage of physical separation to obtain better channel separation.
One box as shown and another for all the potentially noisy components. Obviously, the gainstage for each chn will also be split.
Since we are lucky enough to have the channel split into two, I thought to take advantage of physical separation to obtain better channel separation.
One box as shown and another for all the potentially noisy components. Obviously, the gainstage for each chn will also be split.
Attachments
Hi Grataku,
Are you going with the APOX-1 or APOX-2. The APOX-1 is not split (at least for now).
Otherwise, your drawing looks good.
Dale
Are you going with the APOX-1 or APOX-2. The APOX-1 is not split (at least for now).
Otherwise, your drawing looks good.
Dale
Dale, I always wanted the Apox-2.
Did you have any chance to look at the drawings I sent you?
I have made everything really simple and easy to do. Found the plastic too.
Did you have any chance to look at the drawings I sent you?
I have made everything really simple and easy to do. Found the plastic too.
Hi Grataku,
The drawings looked good. Sorry that I did not reply. I was just about to buy some plastic. I found some 1/2" Lexan. What did you find?
Do you think that we will be able to remove the machining marks?
Dale
The drawings looked good. Sorry that I did not reply. I was just about to buy some plastic. I found some 1/2" Lexan. What did you find?
Do you think that we will be able to remove the machining marks?
Dale
I found 1/4 inch acrylic which I think we should try first.
The beauty of this simplified design is that there won't be any machining of the virgin surface that shows through the window.
Only a minimal recess on the surrounding, even smaller than the one shown on the drawing. We can get this done in no time and see how it looks.
The beauty of this simplified design is that there won't be any machining of the virgin surface that shows through the window.
Only a minimal recess on the surrounding, even smaller than the one shown on the drawing. We can get this done in no time and see how it looks.
Hey Aurora B,
Do you have a source and/or brandname and manufacturer for that rub on/dip silver? I'm trying to track it down.
Thank You
Do you have a source and/or brandname and manufacturer for that rub on/dip silver? I'm trying to track it down.
Thank You
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