S800 Support Thread

[TornadoTed]

I've finished stuffing my 8 boards, took me about 4 hours yesterday and 3 today.

Any idea how long I need to make the wires from the PCB to the pots and switches for Purusha's 4u case?

What about length to the XLR's?

Twisted or not?

 

[mrphotodude]

what kind of poly caps are you guys using on these?
I need to order most likely from mouser...
have a choice of Wima, Rifa, AVX, arcotronics....

just wondering what is the best to use, price range does not vary enough for the amount i am doing(doing some green pre's as well at same time).

 

[peterc]

Wimas are always a good bet, I use the MKS2 or MKS4 ranges extensively. However the different di-electrics do have differing sound qualities.

I do not think there is a lot of difference between different makes for the same type of di-electric, though.

Peter

 

[vulner]

[quote author="peterc"]

>> C25 : SCH=100nf : PS=100nf film : pcb=100uf electrolytic with round space and polarity marker

>> C28 : SCH=470uf elec : PS=470uf@35v elec : PCB=100uf electrolytic with round space and polarity marker

>>C26 : SCH=100uf@25v elec : PS=100uf@25v : PCB 100nf with small rectangle box

Designations for the electrolytics & bypass film caps swapped around.

>> These are on the pcb but not on the run sheet or schematic
>> cpsub 100nf : cpsu1 220uf : cpsu 220uf : cpsua 100nf

These are PSU bypass caps, extra caps added to stabilise the power rails.

Sorry for the confusion

Peter[/quote]

Just to be clear here,
c29 and c30 that are on the schematic but not on the pcb are instead ,split up between the 2- 220uf and 2- 100nf caps that are on the differing pcb layout?
(By the way the 220uf and 100nf caps were included in Colin's parts kit.)
...

 

[matta]

Hey Guys,

I had a few minutes to spare and thought it may help others as things like the polarity and IN/OUTPUT are not marked on the PCB so consulting the Schematic I deduced the following which may help others in their builds.

Built up my first complete channel yesterday and she works like a charm... have the other 15 waiting for pots and switches. I don't want to do them until I'M SURE they work with Purusha's racks.

Cheers

Matt

EDIT: Please note if using one of Purusha's S800 1U racks that the PCB's will go in with the traces facing upwards towards the top of the rack, which is the opposite of the drawing above. This needs to be done to make sure the right bands line up with the panel.

 

[mrphotodude]

thanks matta!

 

[Tungstengruvsten]

and just to clarify, it's just the box/electrolytic caps in the top left of the above diagram that are incorrect/swapped on the PCB?? (c24, c26, c28, c25)

 

[bigswole]

are there any files for us self etchers? Help peterc.

 

[Tungstengruvsten]

Hmmm, the dual 100k rlog pots from Slenderchaps kits don't fit on the PCB...I thought the stereo version allowed the pots to mount to the PCB? DId I mis-read that?

Also - just to confirm - the burgundy coloured 1k5 resistor - is it a 1 watt meant for r43?

 

[Slenderchap]

The burgundy resistor is indeed 1W

Can you clarify exactly what the problem is with the pots.... the PCB was designed to take these pots directly so they should be a perfect fit...

Anyone else had problems with the fit of the pots ?

Colin
www.audiomaintenance.com

 

[Benny]

Yup, the stereo pots did not fit into my boards, aswell.
But i just bent the legs a bit and everything was perfect. :thumb:

 

[Tungstengruvsten]

if the back legs on the stereo pots came off of the other side of the 'wafer' they are mounted on it would line up - looks like they can be bent into place...i'll give that a try...

 

[peterc]

The back legs of the dual pots need to be bent slightly to fit the holes.

First page updated.

Peter

 

[bluezplaya]

I ordered 4 boards and they came in the mail the other day. I stuffed 2 for starters to hear what they sound like. I just wired up the first one and patched it in on some vocal playback. Everything seems to be working as it should, however, the more I boost the H, HM, and LM the more distrorted the signal gets. So I backed down the input signal going in and it seemed to help but there is still a bit of grainy-ness when I boost all the way.

Is this typical of this EQ? Right now I am using the PeterC PSU at +-15v but plan on getting +-18v out of it. Could this be a lack of headroom?

Adam

 

[AJMAC]

where (db of boost) does the distortion become audible, and how much distortion are we talking? (I know this is somewhat relative, just curious)

 

[bluezplaya]

Almost all the way (12-15 db). It's not so much distortion as it is overly resonant in those frequencies.

 

[matta]

[quote author="bluezplaya"]Almost all the way (12-15 db). It's not so much distortion as it is overly resonant in those frequencies.[/quote]

Did you set the on board TRIM pot for unity gain? If you haven'y you are probably causing the EQ to overload, hence the distortion.

Send a signal via a generator at a known value, say 1Khz, +4dBu or 1.23V into the unit and measure the output... it should be equal to that of the input, when it does, you have unity gain.

Cheers

Matt

 

[bluezplaya]

Send a signal via a generator at a known value, say 1Khz, +4dBu or 1.23V into the unit and measure the output

So let me get this straight, feed 1k audio signal into the input jack and measure the output jack for DC volts with a DMM to match the input?

BTW, have you seen my latest post on the Rev. D thread?
http://www.groupdiy.com/index.php?topic=20058&postdays=0&postorder=asc&start=645

 

[bluezplaya]

Does the EQ need to be engaged or bypassed?

 

[Baltimore]

[quote author="bluezplaya"]Almost all the way (12-15 db). It's not so much distortion as it is overly resonant in those frequencies.[/quote]

Never worked on a trident, eh? thats the EQ. Nothing wrong.

This is NOT one of those EQs you can boost forever and still have it sound good. a little goes a long way and it KILLS on electric guitars and can be very cool on snares and toms.

of course, setting it up for unity can't hurt.