Neve 2254 build with ba185, ba191, ba192, ba283

[Spencerleehorton]

Also is the bypass switch 4PDT?

 

[Spencerleehorton]

BA191 Pcb is done moving onto BA185 Pcb, need to match a few components.
I’m using BC184C rather than BC109 and Bc107s.
I did notice that when comparing the original schematic to garameshs 54 version the 100k from gnd to pin P on BA191 Pcb was changed to 51k?  Should I go with 100k or 51k? I’m only building the compressor side of it so thought maybe to put a 100k trim here so I can adjust in case it needs to back to 100k?

 

[Spencerleehorton]

I take it I’m on my own with this build!!! Lol!!

 

[Spencerleehorton]

Just looking at the differences between the ba183 and the ba283, very subtle differences C14 and C15 change from 6.8uf to 22uf, C1 and C8 from 6.8uf to 10uf and C12 from 20uf to 22uf.
I’m going to try to stick to the original schematic  as close as possible apart from using 100uf for the 80uf  caps.
Nearly finished the ba191 and ba185 pcbs and will put together a ba192 as well.

 

[Rob Flinn]

Just looking at the differences between the ba183 and the ba283, very subtle differences C14 and C15 change from 6.8uf to 22uf, C1 and C8 from 6.8uf to 10uf and C12 from 20uf to 22uf.

Different Power transistor,board layout different on the ones I have worked on.

 

[Spencerleehorton]

I think I’ll stick to the higher values for mine, happy New Year everyone!!

 

[Spencerleehorton]

Need some help with doing the switches pots if anyone could help please?

I can see dirty Gary has done a version and consists of :

Threshold, ratio, attack, release and makeup gain.

Threshold seems to have 7 resistors or it can be a 1k log pot?
Adding up the resistors comes to about 250R?

The ratio seems to have 12 resistors?

Attack has 9 resistors and 1 cap?

Release has 10 resistors?

And makeup gain uses 7 resistors or 5k log pot?

Have I got this correct?

 

[Spencerleehorton]

Here is the main schematic, could anyone explain how to do the switches pots please, I’ve got a ruff idea just want confirmation.

 

[Rocinante]

Go to the CAPI website. Jeff has pcb's for making stepped switches but also posts the schematic of how it's laid out.
Dirty Gary's m9del only uses the compressor and not the limiter (which honestly makes sense) but you have the right idea. I am not certain about the input attenuation but the rest of switches are pretty much written out for you e.g. look at the ratio section and you can see how each resistor impacts the circuit.
The really cool thing about Dirty Gary's take was implementing the switch values on a seperate control board. It's a very clever design.

 

[Spencerleehorton]

I get how to make a stepped switch thats no problem, when looking at that schematic the compress ratio part at the bottom could be mistaken for a 3 gang 5 position switch which combines ratio with gain make up, im pretty sure this isnt like this but thats why im asking, just to be clear and save some time on this build!!
the attack i think on this schematic is just slow or fast right?

so this will need a switched pot with, 1k (0.5ms), 1.3k(1ms), 1.8k(5ms), 2k(12ms), 2.2k(25ms), 2.7k(50ms) on it put in between E and D of B185 right?

The threshold i have no clue on as this looks like it could be a 4 gang switch? it has two signal paths and i can see it switching in 1k/33k/1k then 1.8k/15k/1.8k etc but dont understand this config at all?

this schematic has preset output level as well as gain make up? could someone explain please?

I'll try and erase the limit part of the schematic and repost to see if this helps!!

 

[Spencerleehorton]

just found this:

http://10000cows.com/Neve2254Stuff.htm

the schematic is very different!! also has some switch diagrams, hopefully this will help!!

 

[Rob Flinn]

The revision number makes quite a difference to the feature set.  But this is fairly obvious when you look at the fascias for the different revisions.

 

[Spencerleehorton]

Are you able to help explain these switched pots and values please Rob?

 

[shabtek]

switch9 and switch3 are not clarified--is that what you are asking about or is there more?

 

[Spencerleehorton]

I just want to know what value I need for threshold, looks like 5k log?

Ratio now looks like 5 pos 2 gang.

Release 5 pos 1 gang

Make up gain 5k log?

Attack isn’t on that schematic so just need advice on where to put switched pot as have values for it.

 

[Spencerleehorton]

I’ve pretty much figured out the threshold, makeup gain, release and ratio switched pots.

The adjustable attack I think goes in between E and D of ba185, the default value is 470R which is 1ms it says on the schematic?

But on dirty Gary’s info it talks about R16 (270R) on ba191 having link to r29?

Will try and investigate but can anyone make sense of this please?

 

[Rocinante]

What did Igor do?

 

[Tekay]

I just want to know what value I need for threshold, looks like 5k log?

Ratio now looks like 5 pos 2 gang.

Release 5 pos 1 gang

Make up gain 5k log?

Attack isn’t on that schematic so just need advice on where to put switched pot as have values for it.

Threshold control total resistance = 22190 ohm
Make-up control total resistance = 5510 ohm

 

[Spencerleehorton]

Ah ok 22k for threshold and 5k for make up gain as per 5k output pot on 1290.

Just need to work out how to do  adjustable attack, would like 0.5ms 1ms, 5ms, 12ms , 25ms, 50ms, auto don’t know what ms auto is?

Any ideas where I could get igors Build info?

 

[Spencerleehorton]

Well the latest info is that R16 is 270R! Not 4.7k!?
I was getting confused as on the ba185 in about the same position there is a 4.7k!!
Wish there was a correct schematic we could all follow!!
Apparently changing the resistance to larger you get a slower attack, I assume that leg of the 270R on the ba191 between the two transistors goes to the switched pot with different value resistors then goes back to where the leg would normally attach.

Could anyone verify this please?

Going to try the values that I have previously posted and see what happens!!

Pcbs pretty much done now, just a few caps and a transistor to go in.

Will start to build front panel and case and test a few VU meters.

Might have to build ba192 for VU meter but don’t know if there is an easier way yet?