Solo Dallas - SVDS Replica

boby6kiler · Post by **boby6kiler** » 01 May 2020, 07:18

this one: https://reverb.com/item/33262686-soloda ... ?locale=fr
but the pics are not very good

Hotrats · Post by **Hotrats** » 03 May 2020, 22:24

mictester wrote:
... you get a bigger headroom by increasing the supply voltage to 18V and move the bias up - the built-in 1.8V can be over-ridden and replaced with ~6V.

mictester wrote:
My "standard" clean sustain uses an NE 571, NE5532 (because the op-amp inside the 571 is not great),

Mictester, thanks for these useful tidbits

I gather the basis of your circuit is this:

Figure 7 in the 571 datasheet:
https://www.onsemi.com/pub/Collateral/SA571-D.PDF

using a (better) external op-amp ... and THEREFORE providing "access" to ref voltage other than 1.8v
which otherwise isn't accessible ...

mictester wrote:
... and an LM324 for the "variable capacitor" trick (it's in the datasheet) to give really fast attack and a slowed decay. It doesn't pump, and is really nice before some distortion effects, so that you hit them at exactly the "sweet spot" all the time. I also provide a buffered, non-compressed output, to be used as the feed for the sidechain of Mutron or other envelope-driven effects. I run the circuitry from 17.5V, and it doesn't contribute any noise of its own, because the 5532 is so quiet. The distortion is also vanishingly small, so it doesn't colour the sound of the instrument. I have added optional tonal shaping - it's sometimes a good thing to roll off the top end when going into a Fuzz or other distorting effect, because the effect will "paint in" the missing upper harmonics.....

Figure 12 in this app-note:
https://www.onsemi.com/pub/Collateral/AND8159-D.PDF

some background ... https://www.yumpu.com/en/document/view/ ... -walt-jung

very much appreciate your insights
HR

Thefamilycurse · Post by **Thefamilycurse** » 13 May 2020, 00:33

Have any of you completed the EX tower ? If so, I've got some questions for you about building.

Thefamilycurse · Post by **Thefamilycurse** » 22 Jul 2020, 19:23

Anyone replica the tower version yet?

Post by **modman** » 23 Jul 2020, 12:16

Thefamilycurse wrote: ↑22 Jul 2020, 19:23 Anyone replica the tower version yet?

What is different from that EX Tower version compared to what was traced?

Mr.TYR · Post by **Mr.TYR** » 02 Aug 2020, 07:59

modman wrote: ↑23 Jul 2020, 12:16
Thefamilycurse wrote: ↑22 Jul 2020, 19:23 Anyone replica the tower version yet?
What is different from that EX Tower version compared to what was traced?

EX Tower also has an optical rectifier in the preamplifier (Limiter), better power supply and compander filtering, preemphasis and deemphasis for the compander and VU meter.

Thefamilycurse · Post by **Thefamilycurse** » 01 Mar 2021, 05:10

Can someone build an EX tower amp top replica version?

moonshiner · Post by **moonshiner** » 05 Mar 2021, 04:36

Anyone do a stripboard layout on this ?

Reachahighernoon · Post by **Reachahighernoon** » 19 Oct 2023, 15:42

Hey guys, so I recently built my own version of this. Problem is that it is EXTREMELY noisy, like EXTREME levels of distortion background noise

This is the schematic I used, note that I omitted the inductor and I used a CoolAudio V571 instead of the SA570

I audio probed it and the noise seems to come only after the compandor IC, so either there's something wrong with my schematic or the IC itself, any opinions?

Edit: I solved the issue by deleting everything after the compandor

Solo Dallas - SVDS Replica [traced]