Coming mini "Black Box" Pre amp Master!

[NYMo]

3 humps

Obviously not a Bactrian !

 

[barfle]

3 humps

When I was working as an EE, I told people that I could put ten pounds pf s**t in a five pound bag, as long as the customer was willing to pay the price of double-density s**t. Looks like you have that skill as well.

 

[LetsRecapVintageHIFI]

Dear All

Just for a bit of fun and because the really clever bits of the new mini pre amp are kept in the DSP software, I have decided to share with you guys the FIRST CUT schematic that Dave the Bitch has been working on (he is on sanity leave for a week).

The front panel schematic has not been put to CAD but its just a bunch of pots and switches, the interesting stuff is in the main board circuitry. Please be tolerant that Dave always draws his schematics in a tedious, hard to read and put mentally together hierarchical style - I personally like one big connected diagram!!

Its probably full of stuff ups and general brain farts but it gives you guys a sniff that this is not just a toy!

Have fun copying it, if you can you deserve it!

 

[LetsRecapVintageHIFI]

Just add two more bits and nibble on that for awhile Chucky.

 

[Soundfield]

Hi Chucky, I've just noticed that there appears to be an LED above the 'Level' control - what is the purpose of that?

 

[chucky3042]

Hi there

Please put any comments on the preamp we are working on and de hiss, de click, mechanics HERE

 

[DuncanS]

Hi there

Please put any comments on the preamp we are working on and de hiss, de click, mechanics HERE

You could add in the stereo/surround enhancer that the others have talked about, so coupled with an SM would help the Involve mode do stereo to surround

 

[chucky3042]

I actually like the idea, but thinking about it we need access to the rotated 90 degree stuff, so probably keep it in the same box but with an extra knob.

 

[par4ken]

Back in the day when I was building projects from almost every issue of Electronics Today International, I built this click eliminator. It used a TL083 op amp (a TL082 in a 14 pin package) as a preamplifier. It then used a bucket brigade delay chip to delay the signal enough for the click detection and muting circuit to work. The signal was momentarily muted when a click was detected this done via a 4066 CMOS analogue switch.
The unit connected before the RIAA preamplifier. I added a relay to bypass the unit when not in use, as can be seen in the picture. The power supply was in a separate box, connected via a 3 pin DIN connector. While it did work it coloured the sound too much for my taste.

I then tried a different circuit that was published in either Popular or Radio Electronics. As I recall it came after the RIAA preamplifier. Instead of a bucket brigade delay it used an all pass network (like in our matrix decoders) to generate a slight delay. Sadly that was one project that I never got to work properly.

 

[chucky3042]

Back in the day when I was building projects from almost every issue of Electronics Today International, I built this click eliminator. It used a TL083 op amp (a TL082 in a 14 pin package) as a preamplifier. It then used a bucket brigade delay chip to delay the signal enough for the click detection and muting circuit to work. The signal was momentarily muted when a click was detected this done via a 4066 CMOS analogue switch.
The unit connected before the RIAA preamplifier. I added a relay to bypass the unit when not in use, as can be seen in the picture. The power supply was in a separate box, connected via a 3 pin DIN connector. While it did work it coloured the sound too much for my taste.

View attachment 111758

View attachment 111759


I then tried a different circuit that was published in either Popular or Radio Electronics. As I recall it came after the RIAA preamplifier. Instead of a bucket brigade delay it used an all pass network (like in our matrix decoders) to generate a slight delay. Sadly that was one project that I never got to work properly.

I forgot about that one. Do you remember the month/ year?

 

[par4ken]

I forgot about that one. Do you remember the month/ year?

It was in the May 1980 issue of the Canadian version, I'll look to see if I can find the Australian and UK issues as well.
Electronics Today International (Canada) May 1980

 

[chucky3042]

It was in the May 1980 issue of the Canadian version, I'll look to see if I can find the Australian and UK issues as well.
Electronics Today International (Canada) May 1980

I should have it, I will go hunting