1176 in 51x/500 format: FEELER. Goto page 5 for pre-orders.

[drumgod52]

Very very cool,  how soon can I get a couple?

 

[Neil]

   

I'm in. When and how much?

Neil

 

[Igor]

Thanx Tubemooley!
I think "sick bastard" is same as ПадОнаГ in Russian Very pleased to hear!

who's DOA is that with the LED's? I want some of those. The one with the transistors wrapped in copper foil for thermal coupling.

Mine, 2SK389 at input, cascode topology, pretty hot, very fast, low open loop gain, high out current.
Same as used in La-Vi console (TanTan studios, Israel).

"I want one" : Please some patience. Let me test it and get rev.1.2 PCB's first.

F76 test results.

Still not get back my 51X rack.

Results seems to be close to real unit.
I checked with "original" 1176 amps which fits same DOA sockets,
and another power supply for +/-24V, today, the results seems close to what I got yesterday.

So than...

Input amp: OPA604
Output amp: my circuit.
AMPS: measured with what I had in-hand.
Nothing special as distortion and most of sound comes from distorting FET and trunny's.
Input transformer: O-12 clone, Altran C3837-1, from Hairball.
Input: 600 Ohm attenuator from Hairball.
Output transformer: Lundahl LL1524, output load 1Kohm, no Zobel network.

Supply: +/-16V
Current draw (compressor IN, output +10dB, 1.2KOhm coil DCR relays used): +62/-55 mA.

All measured in dBv to simplify math. 1dbV=1V RMS.
Some numbers of course will look better in dBm/600.

Audio part, no FET.

Freq responce:
1kHz 0db, 20Hz +0.3dB, 20Khz -0.2dB, 40kHz -0.8dB.

Noise: /WITHOUT ANY WEIGHTING FILTERS!
IN=min, input shorted, no signal source, OUT=max: -67dB.

S/N at input/output controls approx. at 14hr,
output signal 1db below clipping point: about 89dB.

Output clipping point: +25dB.

Max gain: 37dB.

Distortion at +10dB out:
20hZ 0.18%, 1kHz 0.01%, 10k 0.008%.

With FET inserted, BIAS adjusted for -1.0 db.

Distortion after adjustment
(1kHz, input some db's before compression starts): 0.04%
Can be adjusted for more, of course.

Ratio measurement. Input adjusted for 2db gain reduction at
-10 db of analyzer's out; compressor's out ref'd to zero.
Than, analyzer's output raised to 0db and +10 db, compressor's out measured.

Ratio:2
In -10db Out Ref.0db
In   0db Out Ref.+4.6db
In +10db Out Ref.+7.7db


Ratio:4
In -10db Out Ref.0db
In   0db Out Ref.+3.2db
In +10db Out Ref.+5.3db


Ratio:8
In -10db Out Ref.0db
In   0db Out Ref.+1.5db
In +10db Out Ref.+2.5db


Ratio:12
In -10db Out Ref.0db
In   0db Out Ref.+0.8db
In +10db Out Ref.+1.5db


Ratio:20
In -10db Out Ref.0db
In   0db Out Ref.+0.45db
In +10db Out Ref.+0.85db

SLAM:
In -10db Out Ref.0db
In   0db Out Ref.+0.8db
In +10db Out Ref.+1.7db
Distortion raised, of course

Etc.

Will post more info when get back my 51X rack.
Update: will test in studio, inside 51x rack, this weekend.

 

[Igor]

Update.
Best news: SOUNDS GOOD!
Was compared to black face original unit, IMHO rev.F.
Same character of compression.
Objectively, F76 distorted a bit less and had bit less hiss.
/hehe, all this is easy to fix
I liked the bottom end with Altran O-12 clone, 600 Ohm T-pad and Lundhall1524 out
more than original unit.
The rest is crispy punchy sound talks I hate.

Changing some misc things on front panel, PCB rev.1.2 is ready,
testing again and it is here.

Is there some interest in 51X F76 PCB sets? Metal works (bracket)?

 

[zayance]

8) 8), I'm in for two, bracket yes, i don't think we need metal cover for this :

Edit, yes as Audiogimmer, frontpanel standoffs etc... could be cool less things to do on our sides, and the faster we can use it 

 

[AudioGimmer]

Hey Igor.

I think something like your mixbuzz kit would be good, i.e. PCBs and all metalwork/front panel/brackets/standoffs etc.
It's the same dimensions for lunchbox and 51x racks isn't it?

The sweet part about the mix buzz was the accuracy of the metalwork & front panel etc. [All the stuff I'm not good at!]

AG

 

[RedNoise]

Very good news!!I'm in for two pcb+metalwork+standoffs (like the buzz in fact)
cheers!

 

[ultra-alex]

...
Is there some interest in 51X F76 PCB sets? Metal works (bracket)?

there is. ;D

 

[briomusic]

I'd be in for one-two kits depending on price. I like the way peter purpose puts his kits together, pcb, metalwork and all the fiddly stuff (i.e. the only one model of toggle switch that will fit, etc).
I prefer to chose and order my own resistors, caps etc.

 

[Igor]

That's good idea, to supply kits with all "hard to get" stuff.
One thing is, there are three of Grayhill switches, they aren't cheap
(Digikey shows about $18, but no stock, availability-October (!)
other sources are more costy (I bought now at Farnell, about $25/switch).
Actually, only one 2x6 switch is must, two 1x12 switches can be replaced with pots,
but what I thought, is, if get to 30-50 orders at least, the price drops significantly.
I cannot supply resistors/transistors/capacitors with kits, but things like
LM3916, FET's, especially when somebody needs matched stereo pair,
Grayhill switches, toggle switches, etc, easy. We even can work out a deal on
LL1524 transformers etc.

For guys who want it for real cheap, there's another option:
front panel PCB which fits into 1RU and possibility to use analog meters!
This way, 2 compressors can fit into 1RU. IMHO cool alternative to dist**sor...
taking into account output transformers and discrete stages

Cool than....write here, will try to do my best.
Without killing my brain with too much stuff, of course

 

[AudioGimmer]

Igor

I think offer a package with all the Grayhills and matched components [maybe trafos too?] where appropriate. People can choose to make a top of the line version with this kit, or a more home brewed version with pots and self matched components. I think enough people would be in for the Grayhills  to make it cost effective as a group buy.

Mind you, a 1U 2 channel version sounds pretty sweet too.

Decisions decisions..... 

AG

 

[briomusic]

just to add, obviously it is always possible for 3rd party shops to offer component kits, like slenderchap does for PP EQN or ptownkid for the 51xPSU. this is what I love about the bustling markets of prodigy village  ;D ;D

 

[Neil]

That's good idea, to supply kits with all "hard to get" stuff.
...
Cool than....write here, will try to do my best.
Without killing my brain with too much stuff, of course

Kits with "hard to get" stuff sounds great! If you can get a deal on transformers that's good too, but probably not necessary. Caps and resistors I'd say definitely not necessary, since most probably have spares lying around to use from other projects.

Thanks Igor!

And definitely don't do anything to kill that brain!  

 

[ultra-alex]

just to add, obviously it is always possible for 3rd party shops to offer component kits, like slenderchap does for PP EQN or ptownkid for the 51xPSU. this is what I love about the bustling markets of prodigy village  ;D ;D

very good idea, brio! maybe we can even swap the lars lundahl with a carnhill...  ;D
just kidding. 
cheers, alex

 

[Ryake]

I'm in for one kit similar to the MixBuzz. Also would be interested in the group buy for some of the more expensive parts.

 

[jandoste]

alternative to dist**sor...

I'm in !

 

[Baltimore]

Im in for 2 pcb/metal/hard to get stuff.

 

[bigswole]

i'd love to have 2 that fit into a 1ru space

 

[stereokillah]

i'll combine with rednoise for two with hard compenets if i've got the fund when it's ready

 

[AudioGimmer]

In case I wasn't clear, I'd be in for 1 or 2 depending on price.....

Not going to race Stereokillah to assemble them tho: that guy is FAST!!    ;D ;D


The Gimmer