Clone is nearly done

[Tony Allgood]

Hi,

Nearly finished the TB clone. A few things remaining:
1. To try out the CA3046 array in place of the 2291 (obsolete) and 1583
pairs in the filter.
2. To reduce the amount of CV feedthrough in the VCA. I am hoping a trim
type adjustment will work here, like on a 3080.
3. To put the lot into a nice box, and rack it up and play for a bit.
That why I can find any niggles that need ironing out.

To those who have been following. I have kept the VCA chip. It appears
to add some clipping distortion to the signal. I have had many mails
relating to the fact that the VCA cannot be subbed with a 13700 or 3080.
Too much like a black art that one. The BA662A stays. Anyhow, Roland
seem to have plenty spare. I can supply these with the boards if people
want.

The EG trigger signal is now always connected to trigger the slide
circuit. This adds a 1mS slide to every new note. I can't really say I
noticed the difference, but it was easy to add and might go someway to
simulate what is going on in the TB.

The mixer section is staying too. I have put it after my own overdrive
circuit. The mixer actually clips asymmetrically. It has an interesting
affect on the sound, when the accent is fired. It will also have a
'servo' balanced output. The problem with using CV convertors, you can
easily get ground loops.

I am using the velocity CV to control accent and slide. It works very,
very well with Cubase and the MC303 step time sequencer/arpegiator. I
spent a good hour just playing with the MC's arp. Amazing. Accent and
trigger inputs are also provided if users want to use them. Mind you it
makes for a very interesting playing technique when using a keyboard. I
got the hang of it after a while. But it was like having four synths on
one keyboard. Weird, but useful.

The power supply is a 723. GREAT. With a 7912 doing the stuff for the
op-amps. Current consumption is very low. About 30mA for the positive
and 10mA for the negative.

Tony C has OK'd the schem to go on the archive. It should be up sometime
in the new year.

Best wishes to you all,

Tony Allgood, Cumbria, UK