Hi All
Some pics of my latest franken-build - a channel strip using :
- JLM powerstation psu
- JLM 99 pre with lundahl traffo, 2520 doa in first position, 990 doa in second
- JLM fet DI and go-between
- Foote led meter pcb
- Gyraf pultec with haufe and lundahl traffos with a 12BH7 in the srpp
- MNats/Gyraf 1176 rev J with no input traffo and a haufe output traffo
- veroboard relay bypass for eq and comp
I get a noise floor from -65dBu(mic, line) to -61dBu (guitar) with an output of around +24dBu
with the compressor and eq active. Bypassing the eq makes no real diff to noise floor, bypassing
the comp drops the noise by around 10dBu.
So best noise is -72dBu with only the preamp and the output section of the 1176 in circuit.
It sounds fanastic of course
This is the third of these channel strips I've done, the first two being with neve style inputs
and eq make up. it is the best performer of the three, although not by much.
Tricky bit was finding the right combo of ground connections for the various bits to get
the best noise performance. Basically trial and error (70%), luck (20%) and theory (10%)
Also, getting all the power rails right took a little effort.
But I have to say, I am happily surprised at how good the performance is and how quiet
it is. The 1176 is not the quietest design in the world! And I am not the neatest wiring guy around
- although they are all sound mechanically and safe.
Its just that I don't really go in for wiring looms on prototype, one-offs.
And I am always trying to find the weakest link, noise wise so moving wiring and so on around.
I added a thresh-hold pot (1M linear) to the 1176 (as provided by mnats on his revD pcb but not on the rev J/H)
and that made a huge difference to the control-ability of the 1176. I can now get less compression without
having to sacrifice so much thru-gain meaning my signal to noise at the output of it all is much better.
This was probably the key difference in the usability of the unit of the previous my ones.
I always struggled to get less compression without reducing the 'level' knob to the point where the signal
would sound dull and lifeless. I can say all my future 1176 builds will include this control.
All in all a great experience that has really pushed my skills forward a long way in all sorts of ways,
especially in understanding of gain staging, signal to noise and perfornance testing.
Thanks for checking it out!
Some pics of my latest franken-build - a channel strip using :
- JLM powerstation psu
- JLM 99 pre with lundahl traffo, 2520 doa in first position, 990 doa in second
- JLM fet DI and go-between
- Foote led meter pcb
- Gyraf pultec with haufe and lundahl traffos with a 12BH7 in the srpp
- MNats/Gyraf 1176 rev J with no input traffo and a haufe output traffo
- veroboard relay bypass for eq and comp
I get a noise floor from -65dBu(mic, line) to -61dBu (guitar) with an output of around +24dBu
with the compressor and eq active. Bypassing the eq makes no real diff to noise floor, bypassing
the comp drops the noise by around 10dBu.
So best noise is -72dBu with only the preamp and the output section of the 1176 in circuit.
It sounds fanastic of course
This is the third of these channel strips I've done, the first two being with neve style inputs
and eq make up. it is the best performer of the three, although not by much.
Tricky bit was finding the right combo of ground connections for the various bits to get
the best noise performance. Basically trial and error (70%), luck (20%) and theory (10%)
Also, getting all the power rails right took a little effort.
But I have to say, I am happily surprised at how good the performance is and how quiet
it is. The 1176 is not the quietest design in the world! And I am not the neatest wiring guy around
- although they are all sound mechanically and safe.
Its just that I don't really go in for wiring looms on prototype, one-offs.
And I am always trying to find the weakest link, noise wise so moving wiring and so on around.
I added a thresh-hold pot (1M linear) to the 1176 (as provided by mnats on his revD pcb but not on the rev J/H)
and that made a huge difference to the control-ability of the 1176. I can now get less compression without
having to sacrifice so much thru-gain meaning my signal to noise at the output of it all is much better.
This was probably the key difference in the usability of the unit of the previous my ones.
I always struggled to get less compression without reducing the 'level' knob to the point where the signal
would sound dull and lifeless. I can say all my future 1176 builds will include this control.
All in all a great experience that has really pushed my skills forward a long way in all sorts of ways,
especially in understanding of gain staging, signal to noise and perfornance testing.
Thanks for checking it out!