APOX-1 Update
As promised, here are the results of the changes that Craig whipped up today to help with volume change pops and to avoid high impedences at high volumes:
1) NO POPS
2) HUM is INAUDIBLE (except at settings 240 and above). I suspect this is residual hum from my XBOSOZ, not the impedence issues.
I am a very happy camper! Suffice it to say that Craig and I were confident that we would figure out the problems, but hearing is believing.
The only "bad" news is that the slope about -15dB is not perfectly straight. Probably worth the compromise.
The new IR boards arrived today. Only waiting for the following parts:
1) IS1 boards (Should arrive by Wed)
2) Rotary encoders. (Still show as May 1 ship date at digikey)
3) Power supplies. (Should arrive by Wed)
Dale
As promised, here are the results of the changes that Craig whipped up today to help with volume change pops and to avoid high impedences at high volumes:
1) NO POPS
2) HUM is INAUDIBLE (except at settings 240 and above). I suspect this is residual hum from my XBOSOZ, not the impedence issues.
I am a very happy camper! Suffice it to say that Craig and I were confident that we would figure out the problems, but hearing is believing.
The only "bad" news is that the slope about -15dB is not perfectly straight. Probably worth the compromise.
The new IR boards arrived today. Only waiting for the following parts:
1) IS1 boards (Should arrive by Wed)
2) Rotary encoders. (Still show as May 1 ship date at digikey)
3) Power supplies. (Should arrive by Wed)
Dale
I don't know if the above is bad news really.
As some of you know I wrote a C program to try to make the stepsize between steps as linear as possible by searching through all possible attenuation values.
unfortunately due to the way the graphs go, there are not alot of choices at very highest volume settings.
This resulted in a few of the top volume settings to be repeated
I decided to make a compromise.
So I changed my program to disallow any repeated volume settings. This made the high volume settings have a slight curve in the graph. But it also allowed more steps in the higher volumes
I also eliminated the higher impedance values at the higher volume settings.
I also implemented the anti-popping scheme.
It sounds like everything was working great!
-Craig
enclosure
Hi grataku,
Looks nice! As the DIPCHIP team already knows I plan to
implement the APOX control system in my existing pre, which
consists of 4 (four) enclosures: 3 audio units (l, r, phono)
and one PSU & control unit inspired by the big X-pre.
Uli
grataku said:
Hi grataku,
Looks nice! As the DIPCHIP team already knows I plan to
implement the APOX control system in my existing pre, which
consists of 4 (four) enclosures: 3 audio units (l, r, phono)
and one PSU & control unit inspired by the big X-pre.
Uli
Immersion plating
In close accordance with Mr. Murphy, my regular supplier has discontinued this product.....of course..Will se what I can find in my old catalogues...
A google search for "Immersion silver plating" gave lots of hits though, among others:
http://www.uyemura.com/products.htm#ELECTRONIC
and a product called Presa RGA-14
http://www.uyemura.com/news11.htm
This Co. also had gold plating solutions!
In close accordance with Mr. Murphy, my regular supplier has discontinued this product.....of course..Will se what I can find in my old catalogues...
A google search for "Immersion silver plating" gave lots of hits though, among others:
http://www.uyemura.com/products.htm#ELECTRONIC
and a product called Presa RGA-14
http://www.uyemura.com/news11.htm
This Co. also had gold plating solutions!
APOX-4
Hi guys,
Well you know I can't resist but to make at least one new schematic each week.
Here is the APOX-4, It is exactly like the APOX-1, but it only handles a single channel.
This will allow people to add balance control,
via the APOX-IR1.
(The APOX-1 switched the volume of both channels at the same time using a DPST relay)
Now if only I can follow through with the other schematics I made, we can start offering these boards soon.
Petter has graceously offered to fine tune the board layout for the APOX-4.
Petter,
Dale should have mailed you the eagle schematic and board files already.
And thanks to Peter Daniel and others who suggested the APOX-1 be split up into two boards.
Thanks Petter and Peter,
Craig Beiferman
Hi guys,
Well you know I can't resist but to make at least one new schematic each week.
Here is the APOX-4, It is exactly like the APOX-1, but it only handles a single channel.
This will allow people to add balance control,
via the APOX-IR1.
(The APOX-1 switched the volume of both channels at the same time using a DPST relay)
Now if only I can follow through with the other schematics I made, we can start offering these boards soon.
Petter has graceously offered to fine tune the board layout for the APOX-4.
Petter,
Dale should have mailed you the eagle schematic and board files already.
And thanks to Peter Daniel and others who suggested the APOX-1 be split up into two boards.
Thanks Petter and Peter,
Craig Beiferman
Update
All of the printed circuit boards have arrived.
I ordered the remainder of the resistor kits today.
The encoders have not shipped yet (digikey still says tomorrow
)
Craig and I will be kitting this weekend.
Thanks again for everyones support!
Dale
All of the printed circuit boards have arrived.
I ordered the remainder of the resistor kits today.
The encoders have not shipped yet (digikey still says tomorrow
)Craig and I will be kitting this weekend.
Thanks again for everyones support!
Dale
April pricing on Apox2
Early in this thread there was discussion of price increases in April. Is today the last day to order at the introductory pricing?
Thanks,
Fritz
Early in this thread there was discussion of price increases in April. Is today the last day to order at the introductory pricing?
Thanks,
Fritz
Hi Fritz,
Unfortunately, Craig and I re-calculated costs and realized that even when we bought in quantities of 20, the prices that we posted just let us break even.
Within a couple of days, Craig and I will update the prices. We may wait until the first 20 kits are accounted for. We are at 15.
Best Regards,
Dale
P.S. Please email me directly if you would like to investigate alternate payment options...
Unfortunately, Craig and I re-calculated costs and realized that even when we bought in quantities of 20, the prices that we posted just let us break even.
Within a couple of days, Craig and I will update the prices. We may wait until the first 20 kits are accounted for. We are at 15.
Best Regards,
Dale
P.S. Please email me directly if you would like to investigate alternate payment options...
price increases
Fritz,
I actually did raise the price for the resistor packs a little today.
We were actually losing money after shipping charges.
And yes, today is the last day.
There will be price increases tommorow. Sorry!
We tried to make the price as low as possible by buying in bulk, but we underestimated some of the costs. and made it a little too cheap.
Dale is actually in a battle right now.
We sent the 4 boards to 1 board house.
Dale placed a bid to a board house assuming they included the tooling charge in that bid.
Dale asked for a certain price. they said O.K., and then they returned a bill for that price he offered + the tooling charges on top of that.
Live and Learn!
-Craig
Fritz,
I actually did raise the price for the resistor packs a little today.
We were actually losing money after shipping charges.
And yes, today is the last day.
There will be price increases tommorow. Sorry!
We tried to make the price as low as possible by buying in bulk, but we underestimated some of the costs. and made it a little too cheap.
Dale is actually in a battle right now.
We sent the 4 boards to 1 board house.
Dale placed a bid to a board house assuming they included the tooling charge in that bid.
Dale asked for a certain price. they said O.K., and then they returned a bill for that price he offered + the tooling charges on top of that.
Live and Learn!
-Craig
harvardian said:
I just hope that doesn't involve K-Y...
😱
Sheldon
(who is waiting patiently for his goodies)
PS: order now, you slackers...
Future compatability
Id like to buy for a single ended arrangenment now and maybe change to differential later. Is there a good chance Ill be able to do that in the future and expect a compatable board?
Actually I think Ill buy for differential now but Im curious what would it take to make this a theatre controller? Has this been discussed already? seems like three volume and two input boards plus programming would do that?
Fritz
Id like to buy for a single ended arrangenment now and maybe change to differential later. Is there a good chance Ill be able to do that in the future and expect a compatable board?
Actually I think Ill buy for differential now but Im curious what would it take to make this a theatre controller? Has this been discussed already? seems like three volume and two input boards plus programming would do that?
Fritz
Fritz,
If you want to turn this into a home theater pre-amp you have several options.
If you need input boards, the cost is likely to run high since you will need 1 input board per channel. The cost of the connectors by themselves will be quite high -- then there are the relays (which are more expensive than the others) etc.
Thus, I would invite you to consider whether you will in fact be needing input boards, and if so -- for how many channels? Do you have multiple surround processors? If not, you don't really need any input boards.
As for channels, you have gotten the jist of it. 3 stereo boards will provide 6 channels of attenuation. Now, for the Apox-2 that will be 3 boards.
The situation I describe above is very similar to the one that I am using (digital crossover, requiring 6 channels of analog attenuation). Any input switching I need will be at the digital side. What you might want at some stage is input switching on 2 channels for 2 channel audio provided you can convince the dipchip team to program the other channels into mute (or turn off the following power amps) for stereo mode. Since my crossover is digital, this is not an option that I can make use of.
Another positive thing is that the input switchers don't necessarily have to be in the pre-amp. I can conceivably use just one of them to switch digital sources should I need to.
Petter
If you want to turn this into a home theater pre-amp you have several options.
If you need input boards, the cost is likely to run high since you will need 1 input board per channel. The cost of the connectors by themselves will be quite high -- then there are the relays (which are more expensive than the others) etc.
Thus, I would invite you to consider whether you will in fact be needing input boards, and if so -- for how many channels? Do you have multiple surround processors? If not, you don't really need any input boards.
As for channels, you have gotten the jist of it. 3 stereo boards will provide 6 channels of attenuation. Now, for the Apox-2 that will be 3 boards.
The situation I describe above is very similar to the one that I am using (digital crossover, requiring 6 channels of analog attenuation). Any input switching I need will be at the digital side. What you might want at some stage is input switching on 2 channels for 2 channel audio provided you can convince the dipchip team to program the other channels into mute (or turn off the following power amps) for stereo mode. Since my crossover is digital, this is not an option that I can make use of.
Another positive thing is that the input switchers don't necessarily have to be in the pre-amp. I can conceivably use just one of them to switch digital sources should I need to.
Petter
future compatibility
Fritz,
One of the things I like most about the APOX kit, is that everything is controlled via the I2C bus. So from a connection standpoint. All new boards will be compatible with the APOX-IR1.
(Only a three wire connection to each new board)
The other thing thats nice about the APOX-IR1. is it comes with a bootloader. So when we release a new board. You can upgrade the firmware on the APOX-IR1 via a serial port. Thereby insuring future compatibility with new hardware.
-Craig Beiferman
Fritz,
One of the things I like most about the APOX kit, is that everything is controlled via the I2C bus. So from a connection standpoint. All new boards will be compatible with the APOX-IR1.
(Only a three wire connection to each new board)
The other thing thats nice about the APOX-IR1. is it comes with a bootloader. So when we release a new board. You can upgrade the firmware on the APOX-IR1 via a serial port. Thereby insuring future compatibility with new hardware.
-Craig Beiferman
bootloader
The mention of the bootloader reminds me.
Do some people NOT have access to a windows based PC with a serial port?
If not, maybe I should rewrite the bootloader in JAVA?
Any JAVA experts out there want to make one?
-Craig Beiferman
The mention of the bootloader reminds me.
Do some people NOT have access to a windows based PC with a serial port?
If not, maybe I should rewrite the bootloader in JAVA?
Any JAVA experts out there want to make one?
-Craig Beiferman
Fritz
Single ended versus balanced:
If you go for the Apox-2, single ended versus balanced is a mute (no pun intended) point. The only difference in terms of parts count is that if you do decide to build it single ended, you save like 3 stereo relays which is less than ten bucks.
That is one of the good reasons for choosing phase to phase shunting.
Petter
Single ended versus balanced:
If you go for the Apox-2, single ended versus balanced is a mute (no pun intended) point. The only difference in terms of parts count is that if you do decide to build it single ended, you save like 3 stereo relays which is less than ten bucks.
That is one of the good reasons for choosing phase to phase shunting.
Petter
non PC bootloader
I don't have access to a PC to run the bootloader. Linux is the flavour of choice for me with Macs running a close second. Not that I've bought anything yet, I'm saving up my monies to make a purchase.
What are the possibilities of producing a version for switching DAC inputs? My current project before I move onto a preamp, is a DAC based on PQuadrant's PCM1704 design. My requirements are for accepting multiple BNC inputs and a couple of Toslinks thrown in. It would be fantastic to have an LCD display of the sampling frequency. It would be really great to have digital inputs to the DAC controlled from the same remote as a preamp. Is any of this practical?
I don't have access to a PC to run the bootloader. Linux is the flavour of choice for me with Macs running a close second. Not that I've bought anything yet, I'm saving up my monies to make a purchase.
What are the possibilities of producing a version for switching DAC inputs? My current project before I move onto a preamp, is a DAC based on PQuadrant's PCM1704 design. My requirements are for accepting multiple BNC inputs and a couple of Toslinks thrown in. It would be fantastic to have an LCD display of the sampling frequency. It would be really great to have digital inputs to the DAC controlled from the same remote as a preamp. Is any of this practical?
I have access to intel linux and macs if you need development or troubleshooting help (the mac OS is Mach and free BSD based). One issue you will face is that if it isn't intel, there ARENT any serial ports. This is probably like changing horses in mid-stream, but have you considered USB?
I've done a bit of java, and I can compile whatever you have on the mac platform if you'd like. It's my limited understanding that you are establishing a serial connection and pushing data over the serial port into the uP right? So in terms of the host computer, it would be a serial communication program that listens, then "talks" the new code to the uP, then maybe listens again to make sure the uP got the code. right?
Sheldon
I've done a bit of java, and I can compile whatever you have on the mac platform if you'd like. It's my limited understanding that you are establishing a serial connection and pushing data over the serial port into the uP right? So in terms of the host computer, it would be a serial communication program that listens, then "talks" the new code to the uP, then maybe listens again to make sure the uP got the code. right?
Sheldon
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