Hi Paolo,
Can we clarify what you mean by the following:
1) Lets say that on input 1, you wire it for balanced operation.
2) On input 2, you wire for single ended operation.
On input 2, you would tie your ground to the unused - input. This would get switched in when input 2 is selected.
Now, you would not be able to use inputs for eaither type of connection unless you put an external switch of some kind that would tie the "-" input to the XLR connection or ground it.
We will not be offering programmed or automatic switching of these connection options (unless our arms are severely twisted) as there are already 76 relays for a fully differential system with eight inputs, ground switching, and bypass.
Best Regards,
Dale
Can we clarify what you mean by the following:
1) Lets say that on input 1, you wire it for balanced operation.
2) On input 2, you wire for single ended operation.
On input 2, you would tie your ground to the unused - input. This would get switched in when input 2 is selected.
Now, you would not be able to use inputs for eaither type of connection unless you put an external switch of some kind that would tie the "-" input to the XLR connection or ground it.
We will not be offering programmed or automatic switching of these connection options (unless our arms are severely twisted) as there are already 76 relays for a fully differential system with eight inputs, ground switching, and bypass.
Best Regards,
Dale
Dale,
Looks like the project is coming along well. Hope you will be able to post pictures soon.
Regards,
Jam
Looks like the project is coming along well. Hope you will be able to post pictures soon.
Regards,
Jam
New specs are forming
Hi Guys,
Both APOX-1 prototype boards(relay and remote) are in. They look pretty good. The remote board is built, The relay board
will be shortly.
I have started to compile the list of features for the APOX-2
please visit the
APOX-2
web page for more details. (Too much to post here!)
Dale has thought of some very nice changes that will allow much better future expansion and a cheaper cost.
I'll try to post the schematics of the APOX-2 by the end of this weekend. (If possible! I'm starting to get a bad fever.)
Thanks again,
Craig Beiferman
P.S. Grataku, sorry about your boss!
Hi Guys,
Both APOX-1 prototype boards(relay and remote) are in. They look pretty good. The remote board is built, The relay board
will be shortly.
I have started to compile the list of features for the APOX-2
please visit the
APOX-2
web page for more details. (Too much to post here!)
Dale has thought of some very nice changes that will allow much better future expansion and a cheaper cost.
I'll try to post the schematics of the APOX-2 by the end of this weekend. (If possible! I'm starting to get a bad fever.)
Thanks again,
Craig Beiferman
P.S. Grataku, sorry about your boss!
I don't understand the rationale for having to have that many relays:
1 for each input: 8 (shorting to ground when off)
1 for the output: 1
8 bits of volume control: 8 when going phase to phase or 16 when going each phase to ground.
Total of 17 stereo relays, or 34 mono units which is still quite a few units.
72 relays are a lot of relays! Power draw will potentially be significant.
Petter
1 for each input: 8 (shorting to ground when off)
1 for the output: 1
8 bits of volume control: 8 when going phase to phase or 16 when going each phase to ground.
Total of 17 stereo relays, or 34 mono units which is still quite a few units.
72 relays are a lot of relays! Power draw will potentially be significant.
Petter
Dale, you seem to have a DPDT relay for every input, right?
In the case of balanced inputs one contact is used for the + one for the - in the case where rca is used only one contact is used?
The question is what is the NC contact do on the on the side destined for the - XLR pin?
If you set it up by dividing the inputs into two groups the XLRs and the rca groups then you would need only one relay to operate a grounding of the -pin when one input of the rca group is engaged. This would simply be a shunt to ground outside of the signal path.
Does this help at all?
Actually, I just read the list of features, everything seems to be taken care of, great job! Now you got to back pedal and see how many relays you can safely remove! 😉
In the case of balanced inputs one contact is used for the + one for the - in the case where rca is used only one contact is used?
The question is what is the NC contact do on the on the side destined for the - XLR pin?
If you set it up by dividing the inputs into two groups the XLRs and the rca groups then you would need only one relay to operate a grounding of the -pin when one input of the rca group is engaged. This would simply be a shunt to ground outside of the signal path.
Does this help at all?
Actually, I just read the list of features, everything seems to be taken care of, great job! Now you got to back pedal and see how many relays you can safely remove! 😉
Petter said:
I would expect that only 4 relays (plus a few more for accessory functions) would be engaged at any given time, two for the inputs and two for the volume control, unless they are going with inverted logic, although it maybe more kosher to have the signal go through a powered off relay... 😉
Can you set up a Relay budget?
It would be useful for us to know how many relays are planned to be used split up by section + short description of topology. I still fail to understand the need for 72 units be they stereo or mono.
🙂
Petter
It would be useful for us to know how many relays are planned to be used split up by section + short description of topology. I still fail to understand the need for 72 units be they stereo or mono.
🙂
Petter
Well I count 74 relays:
3 for each of 8 differential i/p ( +, - and gnd switched ) = 24
1 for mute/dim
1 for bypass
24 stage volume control in series style (L & R, + and - ) = 48
total = 74
Seems the fullest solution to me. Presumably for those with budget constraints could drop some inputs and not use differential i/p o/p, also skip the i/p grounding relays?
I'd very much prefer to be using a parallel ladder attenuator. I'd not be at all happy with all those resistors and solder joints in the signal path. This would of course double the number of volume relays!! Which is where the switch controled by a stepper motor ala bentaudio would be ultimate. Better sonics than relays too.
3 for each of 8 differential i/p ( +, - and gnd switched ) = 24
1 for mute/dim
1 for bypass
24 stage volume control in series style (L & R, + and - ) = 48
total = 74
Seems the fullest solution to me. Presumably for those with budget constraints could drop some inputs and not use differential i/p o/p, also skip the i/p grounding relays?
I'd very much prefer to be using a parallel ladder attenuator. I'd not be at all happy with all those resistors and solder joints in the signal path. This would of course double the number of volume relays!! Which is where the switch controled by a stepper motor ala bentaudio would be ultimate. Better sonics than relays too.
Hi guys. I'll try to explain the reason for the ridiculous amount of relays.
Inputs Select.
3 DPDT relays switch in L+,L-,R+,R-,LGND,RGND
For 8 fully diff. channels. That 24 relays. (You don't have to load all of them). Equipment ground loops are completely eliminated since we completey disconnect all unused equipment.
Volume Control.
The volume control for the left channel consists of two series resistor ladders (one for L+ and one for L-)
with a DPST relay to control the tap of the L+ and L-
There are 24 taps. Hence 24 relays
Ditto for the Right channel volume control. ( Therefore 24 more
relays)
finally the HT Bypass requires 4 DPDT relays.
So total we have 24+24+24+4 = 76 relays
see URL=http://www.audioxpress.com/reviews/media/AE398CF.pdf]Article[/URL] at audio express to better understand the reason for the series(stepped) attenuator.
Note: however, that there are much simpler volume control schemes. (Like we did for the APOX-1, but the pre-amplifier will not see constant impedance with any of these schemes. (However you do get more volume control settings.)
What do you guys think?
Thanks,
-Craig Beiferman
Inputs Select.
3 DPDT relays switch in L+,L-,R+,R-,LGND,RGND
For 8 fully diff. channels. That 24 relays. (You don't have to load all of them). Equipment ground loops are completely eliminated since we completey disconnect all unused equipment.
Volume Control.
The volume control for the left channel consists of two series resistor ladders (one for L+ and one for L-)
with a DPST relay to control the tap of the L+ and L-
There are 24 taps. Hence 24 relays
Ditto for the Right channel volume control. ( Therefore 24 more
relays)
finally the HT Bypass requires 4 DPDT relays.
So total we have 24+24+24+4 = 76 relays
see URL=http://www.audioxpress.com/reviews/media/AE398CF.pdf]Article[/URL] at audio express to better understand the reason for the series(stepped) attenuator.
Note: however, that there are much simpler volume control schemes. (Like we did for the APOX-1, but the pre-amplifier will not see constant impedance with any of these schemes. (However you do get more volume control settings.)
What do you guys think?
Thanks,
-Craig Beiferman
Dale thought of a good idea. For people that are using only BNC type connectors. If I switch the L+ and R+ volume control taps with the same relay. The other volume control bank would not have to be loaded.
Any thoughts on that?
I also did some very rough pricing. And want your opinions.
This full blown 8 input volume controller with remote and 76 relays might get up to around $400.
Is anyone willing to pay this kind of money. Or should I go back to
a cheaper (not constant impedance) volume controller?
What to do! What to do!
Thanks,
Craig Beiferman
Any thoughts on that?
I also did some very rough pricing. And want your opinions.
This full blown 8 input volume controller with remote and 76 relays might get up to around $400.
Is anyone willing to pay this kind of money. Or should I go back to
a cheaper (not constant impedance) volume controller?
What to do! What to do!
Thanks,
Craig Beiferman
Please don't throw things at me! But I'm trying to weigh my pricing options.
I would hate to spend all of this time making the APOX-2 and only get a few orders because of the high price.
But would anyone be interested in a much lower cost
PGA2310 based circuit.
Unfortunately this would rule out using the multi-tap transformers.
Thanks,
Craig Beiferman
I would hate to spend all of this time making the APOX-2 and only get a few orders because of the high price.
But would anyone be interested in a much lower cost
PGA2310 based circuit.
Unfortunately this would rule out using the multi-tap transformers.
Thanks,
Craig Beiferman
Pictures
Hey all,
The pcitures of the prototype boards are at
Pictures
I will be creating a wiki to guage interest.
The APOX-2 (series attenuator) will be a bit more expensive than we initially realized (for fully balanced version).
I'll post some details in the wiki. Also, there are lots of front panel options that I'd like feedback on.
1) Would it be better to hard wire all front panel switches, the IR, and the encoder, or would you like them on the PCB. The issue would be that you have to use buttons that we spec and also rotary encoder, etc... Plus you would have to live with our arrangement and spacing options.
If we built it as a board that can mount anywhere, you would just have small cables to the switches, and other stuff.
Thanks
Dale
Hey all,
The pcitures of the prototype boards are at
Pictures
I will be creating a wiki to guage interest.
The APOX-2 (series attenuator) will be a bit more expensive than we initially realized (for fully balanced version).
I'll post some details in the wiki. Also, there are lots of front panel options that I'd like feedback on.
1) Would it be better to hard wire all front panel switches, the IR, and the encoder, or would you like them on the PCB. The issue would be that you have to use buttons that we spec and also rotary encoder, etc... Plus you would have to live with our arrangement and spacing options.
If we built it as a board that can mount anywhere, you would just have small cables to the switches, and other stuff.
Thanks
Dale
Dale,
I was just curious if direct input selection is an option or if you have to toggle thru all the inputs to select one. This might be important for home theater applications where a single remote has to programmed to control the whole system with the use of macros.
Regards,
Jam
I was just curious if direct input selection is an option or if you have to toggle thru all the inputs to select one. This might be important for home theater applications where a single remote has to programmed to control the whole system with the use of macros.
Regards,
Jam
Hi Jam,
Yes, with the remote, you can push the numbers 1 thru 8 to select any of the inputs directly. Or you can cycle using the Channel Up/Down.
Best Regards,
Dale
P.S. Do you have any feedback on the front panel options?
Yes, with the remote, you can push the numbers 1 thru 8 to select any of the inputs directly. Or you can cycle using the Channel Up/Down.
Best Regards,
Dale
P.S. Do you have any feedback on the front panel options?
HI Scraggles,
Actually, we looked at a ladder configuration. It would have the same number of relays, but would require double the resistors.
Also, with either solution, you can use a transformer 😎
Dale
Actually, we looked at a ladder configuration. It would have the same number of relays, but would require double the resistors.
Also, with either solution, you can use a transformer 😎
Dale
I'm interested in remote volume control only. And I want to spend well under a $100. I use the pause button for mute.
However, if you want more of my money, offer a remote volume control that displays the volume level using nixie tubes
.
However, if you want more of my money, offer a remote volume control that displays the volume level using nixie tubes
.
Apox-2
is still my choice, even if it is getting costly. (So will my pre-amp-boards....)
I also would prefer to choose switches and their layout myself.
Arne K
NORWAY
is still my choice, even if it is getting costly. (So will my pre-amp-boards....)
I also would prefer to choose switches and their layout myself.
Arne K
NORWAY
I would be hesitant to get into a 72 relay unit. I would probably not get into a $400 unit. I would also hesitate getting a solid state pot unless it was a multichannel unit.
Here is what I consider would be a great budget:
12 stereo relays to handle 6 inputs, where the inputs are shorted to ground through resistor when relays are in off mode. No need to switch ground.
2 stereo relay to handle high/low gain series resistor
8 shunt stereo relays for volume control. (perhaps mono relays are more effective wrt. space, layout and balance (which I don't require))
2 stereo output relays
Sum: 24 relays
Then: Standardized space for gain stages to be built by us -- that way we can make our own gain stage before and/or after the relays.
Petter
Here is what I consider would be a great budget:
12 stereo relays to handle 6 inputs, where the inputs are shorted to ground through resistor when relays are in off mode. No need to switch ground.
2 stereo relay to handle high/low gain series resistor
8 shunt stereo relays for volume control. (perhaps mono relays are more effective wrt. space, layout and balance (which I don't require))
2 stereo output relays
Sum: 24 relays
Then: Standardized space for gain stages to be built by us -- that way we can make our own gain stage before and/or after the relays.
Petter
I can go along with this. Eight inputs might be too many. I would like to see left and right input and relay boards(mirror image).
In Petters case he can then proceed to build six channels, because weather we like it or not multi-channel is here to stay, Or maybe this could be the next version.
Jam
P.S. Dale I am trying to work out some ideas on front panel switchs, rotary encoder and display placement. I believe the switches and display could share a board and the rotary encoder should have it's own board.
In Petters case he can then proceed to build six channels, because weather we like it or not multi-channel is here to stay, Or maybe this could be the next version.
Jam
P.S. Dale I am trying to work out some ideas on front panel switchs, rotary encoder and display placement. I believe the switches and display could share a board and the rotary encoder should have it's own board.
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