The gain Switch on a 1272?

[JustinS]

Man,

that's freaking impressive!!

Justin.

 

[Family Hoof]

[quote author="soundguy"]wow, I cant at all visualize what those two 12K resistors could do to stop popping?[/quote]
Provide a temporary resistive path to ground in between contacts... like Joe just said.

Yes, it is true. Joe Malone is the king of DIY Neve! Hell yeah! Any price or availability info on those bad boys yet?

Joe,
I was going to e-mail but might as well ask here so as to share the information. Did you get a chance to test your 1:1:1DC output transformer against the Sowter 8751/9160 and Marinair LO1166? If so, how does it hold up? I'll probably order some soon.

 

[chrissugar]

That little thing is amazing Joe.
I remember you posted long ago a picture of that plugin board. Where is that thread?

chrissugar

 

[Shortgypsy]

Ok but what happens if i but on a fixed gain resistor on the prestage and on the secondstage and use the first bank of the switch as a attenuator both stages and then use the second bank to boost the first stage ...is that possible?????

 

[Family Hoof]

[quote author="Shortgypsy"]Ok but what happens if i but on a fixed gain resistor on the prestage and on the secondstage and use the first bank of the switch as a attenuator both stages and then use the second bank to boost the first stage ...is that possible?????[/quote]
You just said keep the first stage fixed and boost it. I don't think that's possible. Most cloners seem to leave the out stage fixed with a 1.5k and use a 2 or 3 bank switch to attenuate the pre stage open and then add boost resistors to the pre stage all the way up to 8.2ohm. If you study the circuit you'll see that the permutations allow much more than that. My version of a 1272 has a 120ohm in the first stage fixed gain (that's the highest Neve used except maybe 91ohm) and 1.5k in the out stage fixed. Input attenuation is controlled with a 5k pot. This gives me about 50dB of continuously adjustable gain and no need for an output attenuator (unless I wanted to overdrive it! :twisted. If I want more it's as easy as changing two resistors. I would boost the out stage more first.

Of course I'm also working on a 1290 that has a 23 position, 3 deck switch in 3 or 5 decibel steps. In calculating all the resistor values for this I've found that many of the values listed around the net for a BA283AV are off. I'll try and post about this after work tonight.

 

[Bauman]

WOW! :shock: Great concept Joe, as usual...

:thumb:

 

[Kev]

[quote author="Family Hoof"] ... Joe Malone is the king of DIY Neve! [/quote]

nah
not just Neve

:green:

so much more on the bench at JLM ... and I don't just mean in development ... stuff that is done.

I told you Joe was a clever fellow
people just don't listen to me so I keep quiet now
smug mode

 

[Mbira]

Good to see ya back Kev . I was starting to wonder...

Joel

 

[Kev]

thanks Joel
:guinness:
not quite back
but I'm never far away

 

[JLM Audio]

:shock: :grin:
Thanks all for the kind words.

I was going to e-mail but might as well ask here so as to share the information. Did you get a chance to test your 1:1:1DC output transformer against the Sowter 8751/9160 and Marinair LO1166? If so, how does it hold up? I'll probably order some soon.

I have all three transformers here so I will try to get a new page up with all the info and graphs ASAP. The JLM1:1:1DC is different as it is a cross between the API2503 litz wire idea but with DC gapping and made the same size as a LO1166. It does not need an output zobel like the LO1166 as it does not change sound under different loads like the LO1166 does. It also has much greater bandwidth than the LO1166 and greater headroom than the API2503. SO it can be used universally in Neve, API Quad8 etc circuits. The top terminal board on the JLM1:1:1DC it only 38mm wide so it fits perfectly on its side in standard 1unit high rack cases.

JLM1:1:1DC on the left and original LO1166 Marinair on the right

But I will get some graphs and web page up to explain it all better.

Joe
www.jlmaudio.com

 

[SUPERMAGOO]

very very very thanks jlm audio!!!!! im from argentina and i have a DAW
and with your schematics can i clon a 1272 neve and its the best!(escuseme my bad englsh). :grin: :grin: :grin: