"Should not be a problem"
Well that is what I thought too and it took me "forever" to figure out what was going on.
I used either an IS1U60 or the IS1U621 -- can't remember now and have not searched the net for the manufacturer. These have built in filter, Amp, Limiter, band pass filter, demodulator and discriminator -- it should have worked, right? Well think again -- they were so sensitive that the slightest bit of stray light (and I mean the slightest bit!) made the volume control lock up at "up" or "down" + my relays would lock up as well. I guess what might have happened was that the entire PIC locked up.
What did work (and was much cheaper as well) was Everlight ELIRM8752 and this was also REALLY SENSITIVE, but not to stray light. I believe that the almost complete metal encapsulation is in part the reason for this receiver working so well.
I am writing this to you so that you won't run into the same agony as I did. If everything works, don't worry, but if it doesn't consider changing out the IR receiver -- I would be willing to pay $1 to save me 2 days of agony!
Petter
Well that is what I thought too and it took me "forever" to figure out what was going on.
I used either an IS1U60 or the IS1U621 -- can't remember now and have not searched the net for the manufacturer. These have built in filter, Amp, Limiter, band pass filter, demodulator and discriminator -- it should have worked, right? Well think again -- they were so sensitive that the slightest bit of stray light (and I mean the slightest bit!) made the volume control lock up at "up" or "down" + my relays would lock up as well. I guess what might have happened was that the entire PIC locked up.
What did work (and was much cheaper as well) was Everlight ELIRM8752 and this was also REALLY SENSITIVE, but not to stray light. I believe that the almost complete metal encapsulation is in part the reason for this receiver working so well.
I am writing this to you so that you won't run into the same agony as I did. If everything works, don't worry, but if it doesn't consider changing out the IR receiver -- I would be willing to pay $1 to save me 2 days of agony!
Petter
Prototype is built (PICS Available)
Dale and I spent the entire day slaving over the soldering iron, and the wire strippers. The result is here.
PROTOTYPE PICS HERE!
The pictures were too big to post here.
The volume control resistors are still missing, but are due to arrive tommorow. We also did preliminary testing on Dale's Pre-amp and power supplies, and everything was working.
The machine shop did not finish the front or back panel yets, but the pictures are probably more clear without them.
What do people think?
Thanks,
Craig Beiferman
Dale and I spent the entire day slaving over the soldering iron, and the wire strippers. The result is here.
PROTOTYPE PICS HERE!
The pictures were too big to post here.
The volume control resistors are still missing, but are due to arrive tommorow. We also did preliminary testing on Dale's Pre-amp and power supplies, and everything was working.
The machine shop did not finish the front or back panel yets, but the pictures are probably more clear without them.
What do people think?
Thanks,
Craig Beiferman
I'll chime in as well.
The preamp in the picture is a BOSOZ with dual power supplies. The transformers are only for the BOSOZ. The APOX is getting power from an external 5V supply.
You can see that we installed one balanced input using PCB mounted XLR connectors and have three single ended inputs using Neutrik RCA connectors (hard wired, but same chassis profile). The ouput is balanced (conversion by BOSOZ).
We will be getting some Holco H8 (.1%) resistors tomorrow. The attenuator will be configured for ~5KOhms. Maximum attenuation will be about -50dB. The attenuator will be on the output of the BOSOZ and will be driving an Aleph2 with the balanced input. For balanced input, I have a LCAudio Zapfilter on my PCM1702 DAC. The RCA inputs (3 of them) will be my singled ended CD player and tuner.
Then ,we can really test. So far, we have verified that we properly switch the input, and that the preamp seems to be working. The real test will be for pops/clicks (expect some minimal clicking) and channel-channel balance.
Dale
The preamp in the picture is a BOSOZ with dual power supplies. The transformers are only for the BOSOZ. The APOX is getting power from an external 5V supply.
You can see that we installed one balanced input using PCB mounted XLR connectors and have three single ended inputs using Neutrik RCA connectors (hard wired, but same chassis profile). The ouput is balanced (conversion by BOSOZ).
We will be getting some Holco H8 (.1%) resistors tomorrow. The attenuator will be configured for ~5KOhms. Maximum attenuation will be about -50dB. The attenuator will be on the output of the BOSOZ and will be driving an Aleph2 with the balanced input. For balanced input, I have a LCAudio Zapfilter on my PCM1702 DAC. The RCA inputs (3 of them) will be my singled ended CD player and tuner.
Then ,we can really test. So far, we have verified that we properly switch the input, and that the preamp seems to be working. The real test will be for pops/clicks (expect some minimal clicking) and channel-channel balance.
Dale
An externally hosted image should be here but it was not working when we last tested it.
Hi Jam,
Do you mean it doesn't match the footprint in the silkscreen?
In fact, I goofed. I got myself turned around and numbered the encoder library part backwards. By mounting it 180 degrees rotated, the connections are correct. Actually, with our small (.925" diameter) knobs, the spacing is good.
I will correct in the final version. That's what protos are for. I also discovered that the display is 1/16" off center. It is not centered on its circuit board as I thought. The only other issue was that the ICD2 connector (6 pin modular) is a bit too close to the micro. Not a problem since we will probably be the only ones using it. But I will correct.
Remember all, we are electrical engineers, not mechanical or designers, so you CAN do a nicer job with your chassis. We just want to show that it will work!
Best Regards,
Dale
Do you mean it doesn't match the footprint in the silkscreen?
In fact, I goofed. I got myself turned around and numbered the encoder library part backwards. By mounting it 180 degrees rotated, the connections are correct. Actually, with our small (.925" diameter) knobs, the spacing is good.
I will correct in the final version. That's what protos are for. I also discovered that the display is 1/16" off center. It is not centered on its circuit board as I thought. The only other issue was that the ICD2 connector (6 pin modular) is a bit too close to the micro. Not a problem since we will probably be the only ones using it. But I will correct.
Remember all, we are electrical engineers, not mechanical or designers, so you CAN do a nicer job with your chassis. We just want to show that it will work!
Best Regards,
Dale
Is it me or are those really really big caps. 
When I ordered some of the Clarity Caps from Meniscus Audio. I had no idea that they were so huge. Those are 10uF/630V
Best Regards,
Dale
P.S. We toyed with remoting the BOSOZ power supply, but I really wanted a single chassis preamp.
When I ordered some of the Clarity Caps from Meniscus Audio. I had no idea that they were so huge. Those are 10uF/630VBest Regards,
Dale
P.S. We toyed with remoting the BOSOZ power supply, but I really wanted a single chassis preamp.
harvardian said:
...which reminds me, yesterday Leo got all dressed up and asked me to take him to your house to play. I guess he has a fond memory of the place.
We enjoyed having him. You are welcome to come over any time. Perhaps, when I have the preamp/amp all together. I'll leave them connected to the WP clones 😉
Dale
Dale
Really Sweet. Drooool
Dale, I notice you are using twin PS boards for your Preamp. Did you also use dual BOSOZ boards?
BTW. I do not suppose the Dynamic Duo want to tackle a nice little DAC for the CDPRO2 that can handle I2s in and offer balanced outputs? Something we can mount in the chassis close to the drive?
Anthony
Dale, I notice you are using twin PS boards for your Preamp. Did you also use dual BOSOZ boards?
BTW. I do not suppose the Dynamic Duo want to tackle a nice little DAC for the CDPRO2 that can handle I2s in and offer balanced outputs? Something we can mount in the chassis close to the drive?
Anthony
Hi Anthony,
I bought the BOSOZ board set from a diyaudio ad. He bought them from pcb-design. The BOSOZ main board is dual mono. The board is actually two seperate circuits with isolated power supplies. So, there is only one board, but it is dual mono.
For the DAC, who knows. Right now, we want to finish the volume kit. We have instructions to write and hopefully order/kit parts.
We are open to suggestions for other projects.
Best Regards,
Dale
I bought the BOSOZ board set from a diyaudio ad. He bought them from pcb-design. The BOSOZ main board is dual mono. The board is actually two seperate circuits with isolated power supplies. So, there is only one board, but it is dual mono.
For the DAC, who knows. Right now, we want to finish the volume kit. We have instructions to write and hopefully order/kit parts.
We are open to suggestions for other projects.
Best Regards,
Dale
Thanks Dale, I am on the Wiki so I assume you will contact me when your ready to place your first production orders?
Anthony
Anthony
Prices are now set
Hi guys,
Dale and I have priced out the kits
I have added a paypal shopping cart to the web site.
Dale and I have tried to be very reasonable with the pricing.
We are trying to take as little profit as possible without killing ourselves. We have priced the boards assuming that we get 20 orders. I am almost certain that you could not layout these boards yourself, and get a better deal then the one we are offering.
Unfortunately, we had to make small changes on the APOX-IR1 (The remote control board) to fix some minor mistakes.
So the next rev of the board will be the final version. But you can order the boards now.
Also, if you would like to spread out the cost over time, (So your wife doesn't hit you), just order 1 or two boards at a time. We are not going anywhere. 🙂
Dale is currently soldering in the resistors to do the final testing of the APOX-2.
All boards will be offered in KIT form. If you don't want a feature listed (like you don't want optical encoders), just e-mail us, and we can work out a deal.
The cheaper APOX-1 version will be coming soon. Pricing of the APOX-2 should be about equal to the APOX-IS1 because the components are almost the same.
But, please see the web page for details.
Click here for pricing info
Thanks,
Craig Beiferman
Hi guys,
Dale and I have priced out the kits
I have added a paypal shopping cart to the web site.
Dale and I have tried to be very reasonable with the pricing.
We are trying to take as little profit as possible without killing ourselves. We have priced the boards assuming that we get 20 orders. I am almost certain that you could not layout these boards yourself, and get a better deal then the one we are offering.
Unfortunately, we had to make small changes on the APOX-IR1 (The remote control board) to fix some minor mistakes.
So the next rev of the board will be the final version. But you can order the boards now.
Also, if you would like to spread out the cost over time, (So your wife doesn't hit you), just order 1 or two boards at a time. We are not going anywhere. 🙂
Dale is currently soldering in the resistors to do the final testing of the APOX-2.
All boards will be offered in KIT form. If you don't want a feature listed (like you don't want optical encoders), just e-mail us, and we can work out a deal.
The cheaper APOX-1 version will be coming soon. Pricing of the APOX-2 should be about equal to the APOX-IS1 because the components are almost the same.
But, please see the web page for details.
Click here for pricing info
Thanks,
Craig Beiferman
Gain stage location
Hi guys,
Awesome work so far 🙂
Just one quick question. Can I place my single gain stage after the volume control board ?
Im jsut wondering casue if so then this would be a nice mating of new tech ( APOX) to old tech ( tube preamp ).
any thoughts ?
is this a horrendous idea ?
Hi guys,
Awesome work so far 🙂
Just one quick question. Can I place my single gain stage after the volume control board ?
Im jsut wondering casue if so then this would be a nice mating of new tech ( APOX) to old tech ( tube preamp ).
any thoughts ?
is this a horrendous idea ?
Hi,
In fact, many(most?) "preamps" have the volume control before the gain stage after the volume control. You would probably want a higher impedence such as 20K-50K
Do you know the input impedence of the tube preamp?
Best Regards,
Dale
In fact, many(most?) "preamps" have the volume control before the gain stage after the volume control. You would probably want a higher impedence such as 20K-50K
Do you know the input impedence of the tube preamp?
Best Regards,
Dale
http://www.diyaudio.com/forums/showthread.php?threadid=7761&perpage=15&pagenumber=1
this is the amp i am currently collecting parts for.
this is the amp i am currently collecting parts for.
harvardian said:
Okay what the heck does that mean? Should the preamp be before or after the volume control, which is it? 🙂
Anthony
Usually the preamps have the volume controls at the input. One reason for that is that off shelf attenuators (the good ones) have higher resistance and they can only be used at the input, usually 50k or so. With mosfets it's recommended lower, around 10k. The preamp's active stage acts as a buffer for the attenuator.
However some preamps produce noise and placing volume control at the output is beneficial. Also, driving a preamp with higher level signal is better. In this case the attenuator shouldn't be more than 5K imp and less is even better.
However some preamps produce noise and placing volume control at the output is beneficial. Also, driving a preamp with higher level signal is better. In this case the attenuator shouldn't be more than 5K imp and less is even better.
Thanks Peter!
That was an incoherent post by me.
Peter said what I intended to say. Most preamps have pots before the gain stage.
For that tube preamp, looks like the guy recommends a 100K volume control. That is no problem.
In fact, you would only need one volume board (APOX-2 board), since it looks like you have a single ended system.
Best Regards,
Dale
That was an incoherent post by me.
Peter said what I intended to say. Most preamps have pots before the gain stage.
For that tube preamp, looks like the guy recommends a 100K volume control. That is no problem.
In fact, you would only need one volume board (APOX-2 board), since it looks like you have a single ended system.
Best Regards,
Dale
APOX-1 schematic has arrived
Hi Guys,
Please go look at rev. 2 of the APOX-1 schematic,
I now incorporates the shunt mode resistance scheme suggested by petter.
It uses half the number of relays, and 8 less resistors, yet doubles the number of possible volume settings(510). and is immune to ground noise (but single ended inputs are not)
See schematic here
If the APOX-1 people are satisfied with this schematic, I'll begin layout tomorrow.
Please give me your vote for rev. 1 or rev. 2
Thanks,
Craig Beiferman
Hi Guys,
Please go look at rev. 2 of the APOX-1 schematic,
I now incorporates the shunt mode resistance scheme suggested by petter.
It uses half the number of relays, and 8 less resistors, yet doubles the number of possible volume settings(510). and is immune to ground noise (but single ended inputs are not)
See schematic here
If the APOX-1 people are satisfied with this schematic, I'll begin layout tomorrow.
Please give me your vote for rev. 1 or rev. 2
Thanks,
Craig Beiferman
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