[BUILD] 1176 Rev A - Back to the beginning...

[gary o]

Which would be the most important capacitor in the rev A for audio flavour C7 C8 C10  or all as important...

Thanks

 

[Biasrocks]

Which would be the most important capacitor in the rev A for audio flavour C7 C8 C10  or all as important...

Thanks

Yes, anything in the audio path will influence the sound to some extent.

C2,C8: 0.15uF,
C7, C10: 1uF

In the pre/line amps are the ones to focus on.

For my build I went with generic poly film caps for the signal path (Panasonics iirc).

I can't imagine the limiter sounding any better with more expensive, esoteric caps in there.

Mark

 

[ilfungo]

Hi guys
why  in the rev A the compression come first then rev D?

Homnite Little Demon
can bring benefits to the sound?

Thanks

 

[Neeno]

Just because the preamp section has more gain.
I don't know if the threshold is the same...

 

[benlindell]

Hey guys, I got a chance to put the original attack pot back in my Rev A today but check out what I'm still getting. Has anyone else seen this with their unit? I have 2 of them and they both do this.

 

[benlindell]

I'm wondering if I can simply add a HPF to this to fix the problem?

 

[Biasrocks]

I'm wondering if I can simply add a HPF to this to fix the problem?

I'm not sure what the problem is Ben.

From your example, which looks clipped and doesn't look like anything sort of signal
that you would normally run through the limiter.

What are you settings on the limiter, what are you running through it?

Could you post some audio so that we can hear what's going on?

Perhaps, I could try running it through my limiter here to see if I get the same thing.

Mark

 

[benlindell]

Sorry, the problem is the low frequency noise after the note. I'm just bursting tone and after it compresses it's adding this low frequency noise. It seems to be directly related to how much compression just happened

 

[Biasrocks]

Sorry, the problem is the low frequency noise after the note. I'm just bursting tone and after it compresses it's adding this low frequency noise. It seems to be directly related to how much compression just happened

What kind of tone? 1kHz sine?

Mark

 

[benlindell]

yup, I first noticed this happening when recording vocals with it. I originally had modified the attack pot with a 100k pot instead of 25k to get a longer attack time so I figured it was that causing the noise but I just pulled the unit and put the 25k pot back in there and it's still do the same thing.

 

[Biasrocks]

yup, I first noticed this happening when recording vocals with it. I originally had modified the attack pot with a 100k pot instead of 25k to get a longer attack time so I figured it was that causing the noise but I just pulled the unit and put the 25k pot back in there and it's still do the same thing.

I ran a test using a 1kHz burst. 4:1 ratio, Attack: 3, Release: 7 about 4db of compression.

My Bluestripe has mods done to the ratio switch/attach pot to mimic the REV AB version,
you can find the info on the "REV A plosives" thread.

I got a bit of noise after the tone, but nothing I would consider a problem.

It was very, very low level and was very short. No way in hell you're gonna hear it under any circumstance I can think of.

I've included a screen shot of my results.

 

[benlindell]

I have done those mods as well I forgot to mention.

You're right that'd you can never hear this noise but it does get in the way when it comes to editing. I like to use these with some extreme compressions some times and I end up with as much noise as was in my screenshot. I've been following the unit with a eq with a hpf filter at around 30, I'd like to be able to use this without also having to use an eq.

 

[Neeno]

Hi Ben !
Why don't you try the mods me and other great contributors of that thread did in the '1176 plosives'
Apart from the simple mod you did on the ratio board, the real rev A had more changes.
Maybe one of the could solve your issue ?

P.S. send me the 'note' you're using to do your test.
I'll try to test my rev A and report back...

Cheers,
Nino
nino (at) studio21.ch

 

[benlindell]

Nino, thanks man, I just emailed you, figured I'd post it here to for anyone else with a a REV A.

http://www.benlindell.com/diy/1176TestTone.wav

My settings were about: 10:00, 10:00, Attack Fully CCW, Release fully CW, 20:1.

Should be a ton of compression but like I said the noise is proportional to the amount of compression it seems.

thanks guys.

 

[mnats]

Hey guys, I got a chance to put the original attack pot back in my Rev A today but check out what I'm still getting. Has anyone else seen this with their unit? I have 2 of them and they both do this.

Interesting. Just posted to my 1108 thread about low frequency oscillation - maybe play with the value of C9 in the Line Amp. Try a 10uF or lower and see if the artifacts disappear...

 

[Neeno]

Those artifacts seem just right to me.
I tried it on my original 1178 and guess what, I've got the same results.

 

[Biasrocks]

Those artifacts seem just right to me.
I tried it on my original 1178 and guess what, I've got the same results.

Ben is saying that it's only a problem for him when editing.

From what I saw, we're really talking about a non-problem. Unless your applying absurd amounts of compression and even then it's could be considered part of the limiters "mojo".

I don't think they had many DAW's around back in 1969, they mostly used their ears.  8)

Mark

 

[benlindell]

That's exactly what I was thinking too as soon as others had the same artifact.

Mnats, I'll try swaping that cap and trying the test again as soon as I have time to open it up.

 

[ChrioN]

some values comparing mnats version to the serial# 125 schematics posted earlier in this thread:

resistor mnats serial 125

r10 2.2M 2.2M
r11 10k 9.1k
r12 1k 2.2k
r13 47k 47k
r14 22k 22k
r15 20k 20k
r16 47k 100k
r17 8.2k 4.7k
r18 3.6k 3.6k
r19 130k 68k
r20 56k 56k
r21 56k 56k
r22 56k 47k
r24 15M 15M
r25 3.3M 3.3M
r26 33k 33k
r27 12k 12k
r28 560r 560r
r29 1.2M 1.2M
r30 120k 150k (t+c?)
r32 39r 39r
r33 560r 560r

 

[benlindell]

I just tried out a 10uf cap in C9 and I'm still getting the same results if not possibly worse.