Spencerleehorton

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #120 on: February 11, 2020, 01:12:01 PM »
I did explain how to do this at the start of the thread.
I just searched for the 2254 Pcbs in google.
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!


r2d2

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #121 on: February 19, 2020, 03:21:05 PM »


Amen

ps:
this forum is not for "share" ?
..... Cracking D.Vader Firewall ...  II-)

Spencerleehorton

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #122 on: February 29, 2020, 02:30:13 PM »
Putting it all in a 2U case, got some nice grey looking Neve knobs!
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Rob Flinn

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #123 on: February 29, 2020, 03:21:03 PM »
Putting it all in a 2U case, got some nice grey looking Neve knobs!

Looking good.  I like those cpc cases.  I use so many of them I can emember the stock number EN55272.  haha
regards Rob

Spencerleehorton

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #124 on: March 21, 2020, 09:46:07 PM »
Thought I’d do a little update,
Both channels compressing but hum on channel 2 and intermittent ratio switch pot?
Still a way off from setting up properly!!!
Will try and run each channel off it’s own Psu and see if it improves hum and check gnd.
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Spencerleehorton

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #125 on: March 29, 2020, 01:54:11 PM »
My main aim whilst all this chaos is going on is to try and get this stereo unit working perfectly and shed some more light on how this circuit works.
Also having a specific schematic to work from and some working voltages on all transistors. (I have a working channel but it still needs some work, have recorded voltages)
I have attached a schematic which i have doctored and would like if possible for it to be checked and verified that its correct.
Once this is then sorted i will alter the circuit and then go through all pcbs and record all components, values and voltages and have a spreadsheet with them all on.
If this would then help everyone else whos having problems I will of cause share all my findings.

Please look at schematic and verify that what i have removed is correct please.
« Last Edit: March 29, 2020, 02:04:22 PM by Spencerleehorton »
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Spencerleehorton

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #126 on: March 29, 2020, 03:10:09 PM »
looking through and comparing neve to audio maintence schematics BA192 has one difference, R8 on Neve is 10k and R75 which is same as R8 is 100k?

which is it?

Well it seems to me to be 100K so, ive found a few errors in cross referencing the schemtics and this error is repeated on both of the same parts of the circuit as well as another resistor which will need to be changed for 100k, both BA191 and BA192 have these errors so i'll change this tomorrow.

Now going to go through the other two cards for possible schematic errors, then update all BOM.
« Last Edit: March 29, 2020, 03:50:03 PM by Spencerleehorton »
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

pvision

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #127 on: March 29, 2020, 06:21:58 PM »
Looking good.  I like those cpc cases.  I use so many of them I can emember the stock number EN55272.  haha

£44-odd from CPC Farnell, 6 in stock
£70 (+ £15.95 delivery from the USA) from Farnell, none in stock
The odd thing being that CPC and Farnell are the same company...

Nick Froome

Spencerleehorton

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #128 on: March 30, 2020, 07:00:04 AM »
Yep, found the same errors in the Neve schematic and cross reference with the audio maintenance schematic, 100k on and 51k are wrong on at least 2 pcbs, so will change and update paperwork, then test.
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Spencerleehorton

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #129 on: March 30, 2020, 05:11:38 PM »
Not hearing compression now? I can see it all working but just can’t hear it?
Will investigate tomorrow
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!


Spencerleehorton

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #130 on: March 30, 2020, 11:28:54 PM »
After much farting around I think I understand it a bit better.
In the ba183 it uses 100k for both r9 and r20 but in the ba283 it uses 10k and 51k.
This isn’t my problem though of why I’m not seeing compression on the output but seeing the GR meter moving?
Time to take it out of the case again and go through it all!!
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Spencerleehorton

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #131 on: March 31, 2020, 06:52:18 AM »
channel two is working but something isnt rightm the waveform keeps jumping around and its not consistant, also the level is way too high.
Im using all different transformers so going to wind 2 output transformers so i know that they are the same, then wind some more input transformers so i know that these are the same.
no point in going on if its all different!!
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Spencerleehorton

Re: Neve 2254 build with ba185, ba191, ba192, ba283
« Reply #132 on: Today at 05:18:03 PM »
I have wound all new transformers as most of the problems i was having, was due to miss match of transformers.
now getting good signal through both channels but I have had to take out of case again and layout on bench.
One channel is not compressing at all, and the other is but the threshold control has problems and its a bit hit and miss?
will look at signal going into BA191 and see if i can trace the signal which leaves the SC back into the Limit SC.
I think the signals output form the limit SC is (A) and goes back into the control Amp on BA185 by (M)?

is this where the compressed signal comes back in?

If anyone could explain the signal flow of the compressed signal please?
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!


 

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