Stripped down transformerless 1176 workalike project

[pvision]

I imagine possibly putting 4 into an enclosure with one VU meter that is swappable between channels.

I thought about that. You could have a momentary pushbutton on each channel to feed the meter

Having a rotary switch to select the channel is obvious but requires two actions. With a momentary switch you can grab the input knob - probably the most used on an 1176, press the button and watch the changes

Nick Froome

 

[Humner]

how is this project going? I've been following with much interest.

So I notice you have these coming in at a 50mm strip - would there be room to tighten this into a 45 or even 40mm strip?

 

[grrrunge]

The board files are ready for production, i just needed a little time away from the project, to be able too look at it with fresh eyes.
I'll order the prototype boards from seeedstudio sometime in the next few weeks, when I've had another lookover, to ensure I haven't missed any bugs in the schematic.

I'd appreciate it a great deal, if someone else would compare the schematics, ad see if i missed something.

 

[grrrunge]

So I notice you have these coming in at a 50mm strip - would there be room to tighten this into a 45 or even 40mm strip?

I've seen several members here looking for an 1176 project that would fit in 1RU.
Once the first unit is built and confirmed working, I'll give it  a shot It's just a matter of redesigning the switch/meter board.
My only concern with that layout is that i'll probably not be able to keep the LED-metering on the smaller board. Best case as see it is a meter resolution of 4 LED's without getting stuff way to cramped together in there.

 

[ForthMonkey]

Following this project.It's what i'm looking for.Waiting for your project results and buy some boards

 

[pvision]

1U? - You would have space for a meter and UREI-style knobs in 1U

I have been thinking that everything should have two channels… Maybe a stereo version in 1U? You don't need two meters or two sets of controls, IMHO. Maybe just separate ins & outs like an 1178

Nick Froome

 

[grrrunge]

My bad, that wasn't specific enough.

What i meant was that at 40x100mm it would be possible to fit 4 modules vertically in a 1RU case, but i would probably not be able to fit the same GR-meter resolution on the standoff board, if i shave off 10mm on the narrow side.
With just two modules in there, there would surely be plenty of room for everything on the front panel, but the standoff boards would have to be different in order to facilitate shared metering.

I'm trying to stay within a 100x100mm and 50x100mm limit for the board sizes, as those are reasonably priced over at seeedstudio. Once you go over 100mm, production prices increase drastically.

I also stand by my initial idea, which is to cut costs where possible.
The power transformer and rack-case are the only "expensive" items left in this project, so the more channels i can get to share the same case and transformer, the better.

 

[pvision]

I also stand by my initial idea, which is to cut costs where possible.

I think it's a great idea. I don't try to divert you from it intentionally!

Nick Froome

 

[grrrunge]

I also stand by my initial idea, which is to cut costs where possible.

I think it's a great idea. I don't try to divert you from it intentionally!

Nick Froome

I didn't think so either. No hard feelings here, I just felt like i needed to explain myself a little further
I like the idea of several available stand-off boards for different applications - 1RU vertical, 3RU horizontal, mechanical metering, LED-metering or no metering - all using the same main board. That's a cool way of providing flexibility IMO.

 

[frazzman]

Any further development on this one ? I've been following the thread with a keen interest.

 

[grrrunge]

Still working on it. It's coming along slowly
I've got a lot of stuff to do at the moment. This semesters EE classes apparently pack a lot of subjects not related to analog audio, so they're a bitch to get through 

 

[ForthMonkey]

Any news?

I was thinking design something like this but if you're already making,i'll get from you.Hardly wait!  ;D

 

[grrrunge]

If you feel like building it before i do, i could make a shared project on seeedstudio?

 

[fjgaston]

Hi,
I'm really interested in building one Asap 
You wrote you can build these for 10 - 12$ per comp (including PCB) ... is it for real ? Where do you buy your components ?
I would gladly have a kit now if it's possible for this price.
I's like to build 2 with transformers and 2 transformerless.
Do you have some idea for the PSU ?
Thank you very much for sharing this project.

 

[grrrunge]

I usually get most components from Tayda Electronics and PCB's from Seeedstudio.

The $10-$12 per channel cost should be possible to reach if you build 10 channels, as that's the amount of board sets you'd recieve from Seeedstudio. Bear in mind that it does not include any PSU or chassis related parts. I suppose a 8 channel version like the one I plan to build would set you back around $200 or so.

I haven't had any PSU related considerations yet. First i need to get the channel running with a lab supply
When that's done I'll measure current consumption under various circumstances, and then I'll be able to design a PSU board that will be able to supply a handful of channels.

I'm sorry about the slow progress on this bugger. I just haven't got a lot of spare time to work on it at the moment :-\

 

[fjgaston]

Hi, thanks for the fast answer,
I'm starting a BOM I'll post it soon, to know if I choose the right components.
I don't know very much about PSU but is it possible to just consider a 8 channel 1176 would use as much power as 8 1176 and build a PSU 8 times bigger than the original 1176 (or 4 times bigger than a stereo unit ?)

 

[grrrunge]

Here's a preliminary parts list. I'd wait with the parts ordering though

You can't simply assume that 8 of these channels will consume 8 times the power of 8 original 1176 channels, as significant changes have been made to the output amplifier. The consumption will most likely be significantly less, and as a result thereof a smaller - and cheaper - power supply transformer will be needed.

Partlist

Exported from 1177KH_REV8.brd at 11/11/15 14.14

EAGLE Version 7.3.0 Copyright (c) 1988-2015 CadSoft

Assembly variant: 

Part      Value          Package   Library              Position (inch)       Orientation

ATTACK    25K            16MM-OCTA potentiometers       (1.75 3.8)            R0
C1        100n           C2.5-2    caps-box             (0.4 1.9)             R180
C2        47µ            050_020   caps-electro         (0.2 1.75)            R270
C3        1µ             C5B5      caps-box             (2.075 4.75)          R90
C4        100p           C2.5-2    caps-box             (0.2 1)               R180
C5        100p           C2.5-2    caps-box             (0.4 1)               R180
C6        6µ8            050_020   caps-electro         (0.2 1.15)            R180
C7        6µ8            050_020   caps-electro         (0.4 1.15)            R180
C8        220p           C2.5-2    caps-box             (0.2 1.9)             R0
C9        6µ8            050_020   caps-electro         (0.4 1.75)            R90
C10       220n           C5B3.5    caps-box             (1.4 1.575)           R0
C11       200p           C2.5-2    caps-box             (1.4 1.45)            R0
C12       6µ8            050_020   caps-electro         (2.95 1.95)           R90
C13       6µ8            050_020   caps-electro         (2.5 2.2)             R0
C14       1µ             C5B5      caps-box             (0.85 1.825)          R180
C15       200p           C2.5-2    caps-box             (1.125 1.3)           R90
C16       100µ           050_020   caps-electro         (0.85 1.4)            R0
C17       100µ           050_020   caps-electro         (2.5 2.5)             R180
C18       22p            C2.5-2    caps-box             (1.4 1.7)             R180
C19       220n           C5B3.5    caps-box             (1.4 2.225)           R0
C20       22n            C5B3.5    caps-box             (1.8 2.85)            R0
C21       100µ           050_020   caps-electro         (0.75 2.55)           R0
C22       100µ           050_020   caps-electro         (1.4 2.55)            R90
C23       47µ            050_020   caps-electro         (0.95 2.55)           R180
C24       1µ             C5B5      caps-box             (1.95 2.05)           R0
C25       10p            C2.5-2    caps-box             (1.95 1.4)            R0
C26       47µ            050_020   caps-electro         (2.05 0.95)           R180
C27       47µ            050_020   caps-electro         (1.85 0.95)           R0
C28       47µ            050_020   caps-electro         (1.95 2.55)           R0
C29       47µ            050_020   caps-electro         (3.15 1.95)           R90
C30       33p            C2.5-2    caps-box             (3.5 1.9)             R0
C31       100n           C2.5-2    caps-box             (3.7 1.9)             R0
C32       HPF            C5B3      caps-box             (2.05 4.3)            R270
C33       330n           C5B3      caps-box             (1.8 4.3)             R270
C34       100n           C5B3      caps-box             (1.6 4.3)             R270
D1        FD333          DO35      diodes               (2.5 1.9)             R0
D2        FD333          DO35      diodes               (2.5 2)               R0
D3        CR11           DO35      diodes               (3.6 2.5)             R0
D4        LED            LED3MM    diodes               (0.1 5.25)            MR90
D5        LED            LED3MM    diodes               (0.275 5.25)          MR90
D6        LED            LED3MM    diodes               (0.45 5.25)           MR90
D7        LED            LED3MM    diodes               (0.625 5.25)          MR90
D8        LED            LED3MM    diodes               (0.8 5.25)            MR90
D9        LED            LED3MM    diodes               (0.975 5.25)          MR90
D10       LED            LED3MM    diodes               (1.15 5.25)           MR90
D11       LED            LED3MM    diodes               (1.325 5.25)          MR90
GR        SPDT           SPDT      stomp-switch         (2.075 5.25)          R90
HPF       SPdT           SPDT      stomp-switch         (2.725 5.25)          R270
IC1       2OPA           DIL08     integrated-circuits  (0.3 2.15)            R180
IC2       TL071P         DIL08     integrated-circuits  (3.6 2.15)            R0
IC3       2OPA           DIL08     integrated-circuits  (1.95 1.65)           R180
IC4       TL074P         DIL14     integrated-circuits  (0.35 4.75)           R270
IC5       TL074P         DIL14     integrated-circuits  (1.05 4.75)           R270
IC6       78L05          78LXX     transistor-regulator (1.7 4.55)            R0
INPUT     A10K           16MM-OCTA potentiometers       (0.3 3.8)             R0
METER_REF 5K             S64W      trimmers             (0.25 4.1)            R180
OUTPUT    A100K          16MM-OCTA potentiometers       (1.025 3.8)           R0
Q-BIAS    2K             S64W      trimmers             (3.6 0.2)             R0
Q1        BC546B         TO92-EBC  trans-npn            (2.775 1.4)           R270
Q2        BC546B         TO92-EBC  trans-npn            (2.775 1.7)           R270
Q3        BC546B         TO92-EBC  trans-npn            (2.775 2.2)           R270
Q4        BC546B         TO92-EBC  trans-npn            (2.775 2.5)           R270
Q5        BF245A         TO92-     trans-misc           (1.125 1.55)          R270
Q6        BC546B         TO92-EBC  trans-npn            (1.125 1.9)           R270
Q7        BC546B         TO92-EBC  trans-npn            (1.125 2.2)           R270
Q8        BC546B         TO92-EBC  trans-npn            (1.125 2.5)           R270
Q9        BF245A         TO92-     trans-misc           (3.6 1.45)            R0
R1        47K            0703      resistors            (2.65 4.3)            R270
R2        56K            0703      resistors            (2.55 4.3)            R90
R3        100K           0703      resistors            (0.3 1.5)             R180
R4        100K           0703      resistors            (0.3 1.4)             R0
R5        1M             0703      resistors            (3.05 1.5)            R180
R6        470K           0703      resistors            (3.05 1.4)            R180
R7        56K            0703      resistors            (2.45 4.3)            R270
R8        47K            0703      resistors            (3.05 1.6)            R0
R9        68K            0703      resistors            (2.35 4.3)            R90
R10       10K            0703      resistors            (0.3 2.6)             R180
R11       10K            0703      resistors            (0.3 1.3)             R180
R12       56K            0703      resistors            (2.25 4.3)            R270
R13       4K7            0703      resistors            (2.5 1.3)             R180
R14       47K            0703      resistors            (3.05 1.3)            R0
R15       2K4            0703      resistors            (2.5 1.6)             R0
R16       270R           0703      resistors            (2.5 1.4)             R180
R17       10K            0703      resistors            (0.3 2.5)             R0
R18       10K            0703      resistors            (0.3 2.4)             R0
R19       10K            0703      resistors            (0.3 1.6)             R0
R20       150R           0703      resistors            (2.75 4.3)            R90
R21       10M            0703      resistors            (2.35 4.75)           R270
R22       182K           0703      resistors            (2.5 1.8)             R0
R23       470R           0703      resistors            (2.45 4.75)           R90
R24       38K3           0703      resistors            (3.05 2.2)            R180
R25       44K2           0703      resistors            (3.05 1.8)            R0
R26       7K68           0703      resistors            (3.05 2.1)            R180
R27       560R           0703      resistors            (2.55 4.75)           R270
R28       4K7            0703      resistors            (3.05 1.7)            R180
R29       27K            0703      resistors            (0.85 2.1)            R0
R30       2M2            0703      resistors            (1.4 1.35)            R180
R31       1K5            0703      resistors            (2.65 4.75)           R90
R32       2K4            0703      resistors            (3.05 2.4)            R180
R33       180R           0703      resistors            (3.05 2.3)            R0
R34       2K2            0703      resistors            (2.75 4.75)           R270
R35       10K            0703      resistors            (0.85 1.55)           R0
R36       47K            0703      resistors            (3.05 2.5)            R0
R37       47K            0703      resistors            (3.05 2.6)            R0
R38       2M2            0703      resistors            (1.4 1.25)            R180
R39       1K             0703      resistors            (0.85 2)              R0
R40       560K           0703      resistors            (1.4 1.9)             R0
R41       470R           0703      resistors            (1.8 3)               R180
R42       1M             0703      resistors            (0.85 2.2)            R180
R43       180R           0703      resistors            (0.85 1.65)           R0
R44       180R           0703      resistors            (0.85 1.25)           R180
R45       270K           0703      resistors            (2.525 3)             R180
R46       200R           0703      resistors            (1.4 1.8)             R180
R47       10K            0703      resistors            (3.6 1.7)             R180
R48       3K9            0703      resistors            (3.6 0.35)            R0
R49       10K            0703      resistors            (3.6 0.45)            R180
R50       7K5            0703      resistors            (1.4 2.4)             R180
R51       22K            0703      resistors            (0.85 2.3)            R180
R52       82R            0703      resistors            (1.4 2.1)             R180
R53       1K8            0703      resistors            (1.4 2)               R0
R54       6K8            0703      resistors            (0.85 2.4)            R0
R55       470R           0703      resistors            (1.95 0.8)            R0
R56       220K           0703      resistors            (1.95 1.9)            R0
R57       12K            0703      resistors            (1.95 2.2)            R180
R58       470R           0703      resistors            (1.95 1.2)            R0
R59       620R           0703      resistors            (0.1 4.55)            R90
R60       33K            0703      resistors            (1.95 1.3)            R0
R61       100K           0703      resistors            (1.95 1.1)            R0
R62       100K           0703      resistors            (1.95 0.7)            R180
R63       470K           0703      resistors            (1.95 2.4)            R0
R64       470K           0703      resistors            (1.95 2.3)            R180
R65       3M9            0703      resistors            (3.6 1.6)             R0
R66       2K             0703      resistors            (3.6 1.2)             R0
R67       10K            0703      resistors            (3.6 1.3)             R0
R68       15K            0703      resistors            (3.6 1.1)             R180
R69       3K6            0703      resistors            (3.6 2.6)             R180
R70       100K           0703      resistors            (3.6 2.4)             R180
R71       470K           0703      resistors            (3.6 1.8)             R180
R72       620R           0703      resistors            (0.1 4.95)            R90
R73       620R           0703      resistors            (0.6 4.95)            R90
R74       620R           0703      resistors            (0.6 4.55)            R90
R75       620R           0703      resistors            (0.8 4.55)            R90
R76       620R           0703      resistors            (0.8 4.95)            R90
R77       620R           0703      resistors            (1.3 4.95)            R90
R78       620R           0703      resistors            (1.3 4.55)            R90
R79       120R           0703      resistors            (0.6 4.15)            R270
R80       110R           0703      resistors            (0.7 4.15)            R270
R81       100R           0703      resistors            (0.8 4.15)            R270
R82       160R           0703      resistors            (0.9 4.15)            R270
R83       130R           0703      resistors            (1 4.15)              R270
R84       180R           0703      resistors            (1.1 4.15)            R270
R85       120R           0703      resistors            (1.2 4.15)            R270
R86       200R           0703      resistors            (1.3 4.15)            R270
R88       620R           0703      resistors            (0.7 4.55)            R270
RATIO     2P6T           CK102X06  switch_std           (3.375 4.375)         MR135
RELEASE   5M             16MM-OCTA potentiometers       (2.475 3.8)           R0
SLAM1     SPDT           SPDT      toggle-switch         (3.375 5.15)          R90
SLAM2     SPDT           SPDT      toggle-switch         (3.375 5.35)          R90
TP1       pad            OCTOGON   supply               (0.1 4.3)             R90
TRACK_ADJ 100K           S64W      trimmers             (3.6 0.9)             R0

 

[fjgaston]

For the ones interested in small size 1176 designs there is a rack 500 unit made by sound skulptor http://soundskulptor.com/uk/cp5176.html
It's different as it uses an output transformer and -15v/+15v but maybe some usefull informations can be gathered on their website.

 

[grrrunge]

Yes, I recall seeing that one. It replaces the entire sidechain with op-amps, and keeps the transformers. Looks cool, but certainly not a budget option

 

[fjgaston]

I was thinking, if I use a compressor as an insert, in TRS on my console, it be unbalanced, so in this configuration it's useless to have a balanced input and a balanced output.
It would be another way to cut the cost ... but maybe you are not going to use them in a TRS insert.