Bozak DJ Mixer Clone - Opened up

[Nejrup]

A quick question.

A BOM of INPUT Card states 2.2nf STYRENE 160V capacitor.
Does it have to be exact 160V ? I suppose not.
The typical styrenes from Xicon are rated at 50V.
Or maybe to go Polypropylene here ?
What capacitor you used at C201L, C201R positions ?

Thanks...

The BOM suggests to go with film instead (https://www.digikey.com/products/en?key ... -4874-1-ND)
I've done it with great results, and I suspect you can hear absolutely no difference between that and a polystyrene cap. If you want to stay absolutely true to the original and go for styrene, ebay is the way to source.

[Exhale]

Turned out absolutely not necessary.
Because you won't able to find styrenes at 160V that easily.
And 50V is more than enough on that position.
Cause it's located in a signal chain, providing treble shelf eq frequency as I understood.

So, no need for 160V.
But PP also shall do the job perfectly.

[home_listening]

Anything mentioned will work, main rail is only 40V. I bought a huge lot of 160V polystyrenes and included them with the PCB and Panel sets I sold, hence the voltage in the BOM.

[/img]

[Krachluigi]

Are there any PCB´s out there?

Or anyone up for another run?

[muzo]

Turned out absolutely not necessary.
Because you won't able to find styrenes at 160V that easily.
And 50V is more than enough on that position.
Cause it's located in a signal chain, providing treble shelf eq frequency as I understood.

So, no need for 160V.
But PP also shall do the job perfectly.

I used EPCOS / TDK Epcos MKP cap for C201 and works nicely.

[muzo]

Are there any PCB´s out there?

Or anyone up for another run?

Last set from my side if you need.
Check your PM.

[Krachluigi]

Thanks for sharing!
I was recently talking with a friend about the Bozak Isolators, which seems pretty hard to find...and we found your website, great work!

Some years ago we just found the Pioneer SF850 crossover / discrete isolator schematic

We might finish building some of Mr Eliot´s design ideas:
http://sound.whsites.net/project153.htm
http://sound.whsites.net/articles/eq.htm#s6

So since my PCB set arrived, I was wondering if anyone integrated an Isolator into this build?

Did a little research and apart from this Eliot Sound PCB´s, there is this pretty interesting prebuilt Isolator kit:
https://bozure.com/iso-2-19%e2%80%b3-isolator-pcb/

Furthermore the creator of this PCB made a little passiv DI Box by using Lundahl transformers.
After a whole day of reading about Palmer, Jensen and Haufe transformers I began to question myself, if thats the only way to get a balanced signal...
As far as I get it, there is also a way of using XLR with no connection to the ground pin.

[Exhale]

If somebody is interested, one silver front panel is for sale.

viewtopic.php?f=74&t=227902&p=3204993&h ... k#p3204993

Private message me regarding details.

[home_listening]

Hey, if take a look at the original schematics the output wasn't balanced at all, hence I was comfortable just using the RCA connector and not adding XLR too.

In the original the output signal goes to pin 3 of the XLR, GND to Pin 1 and pin 2 is left floating. A better choice would be to tie pin 2 to ground via a 12 ohm resistor so at least the output would be impedance balanced (ish). If you do want to symmetrically balance with a transformer the output amplifier has no trouble driving it whatsoever - look for a 600R:600R unit as there is no need for any stepup.

Cheers

Thanks for sharing!
I was recently talking with a friend about the Bozak Isolators, which seems pretty hard to find...and we found your website, great work!

Some years ago we just found the Pioneer SF850 crossover / discrete isolator schematic

We might finish building some of Mr Eliot´s design ideas:
http://sound.whsites.net/project153.htm
http://sound.whsites.net/articles/eq.htm#s6

So since my PCB set arrived, I was wondering if anyone integrated an Isolator into this build?

Did a little research and apart from this Eliot Sound PCB´s, there is this pretty interesting prebuilt Isolator kit:
https://bozure.com/iso-2-19%e2%80%b3-isolator-pcb/

Furthermore the creator of this PCB made a little passiv DI Box by using Lundahl transformers.
After a whole day of reading about Palmer, Jensen and Haufe transformers I began to question myself, if thats the only way to get a balanced signal...
As far as I get it, there is also a way of using XLR with no connection to the ground pin.

[selectorsroll]

hi, has anyone found an off the shelf PSU for this project?
cheers

[home_listening]

Hi All;

I started a facebook group for builders as, for better or worse, facebook offers the widest reach. As mentioned on my website, I have never been able to offer much in the way of support for this project.

The group is called "Fabric Astronaut Engineering Pathos Builders Alliance." and I'd suggest asking questions there so the hivemind can help out. Answers will then be available to all rather than getting burried in a PM.

RePost from the group:

"Hi All. Thanks to everyone who has decided to undertake this project. I really appreciate it and view it as a great support of my work.

However, I have extremely limited time as I am busy with work in addition to audio projects. I was only ever able to offer limited support to people who purchased the PCBs directly from myself and had no plans to offer any support to others. Assisting with builds has been a great chance to meet interesting people from around the globe - but I have to be practical about my situation. I appreciate your understanding.

Its likely that some fantastic people other than myself will be able to answer faster than I can, so I have decided to start this group.

If no one can answer your question, just try it. This is DIY after all and bumping heads with failure and errors is part of the fun, it has to be. If you were after a mixer with no struggles at all, then I have to suggest you purchase a fully built unit.

Progress is not a straight line.

Ask a question with plenty of photos where possible. Please clean your circuitboards with isopropyl alcohol before taking photos of them so that we can clearly see what is going on."

Kind regards -HL

[fragletrollet]

Anywhere to get the pcb's and/or files?

[Luka]

If you sign up to the facebook group some members are selling pcbs

[soup]

There's someone selling pcb's/faceplate in BST. It looks like the files were taken down from fabric astronaut's site, maybe they could get posted here for those who don't fuck with facebook?

[Tonescape]

I'd be happy to host the files if someone can confirm that it would be ok. Not sure which license it is released under?

[Exhale]

If someone is interested.
Panel + set.
viewtopic.php?f=74&t=235025

[roger]

Hi All;

I started a facebook group for builders as, for better or worse, facebook offers the widest reach. As mentioned on my website, I have never been able to offer much in the way of support for this project.

The group is called "Fabric Astronaut Engineering Pathos Builders Alliance." and I'd suggest asking questions there so the hivemind can help out. Answers will then be available to all rather than getting burried in a PM.

Hi, can you or someone else link the group? I am unable to find it under any of the given names/words. Got some juicy beginner questions to ask

[Suf-fuD]

Hi All;

I started a facebook group for builders as, for better or worse, facebook offers the widest reach. As mentioned on my website, I have never been able to offer much in the way of support for this project.

The group is called "Fabric Astronaut Engineering Pathos Builders Alliance." and I'd suggest asking questions there so the hivemind can help out. Answers will then be available to all rather than getting burried in a PM.

Hi, can you or someone else link the group? I am unable to find it under any of the given names/words. Got some juicy beginner questions to ask

https://www.facebook.com/groups/1080577452325250

[roger]

Thank you!