1108+508eq

[Piscolabis]

Hi,

Im bulding a 1108 preamp with the Mnats layout that I want to adapt to 500 series.
And I am drawing the 508 equalizer pcb with eagle cad, but I dont know the values of the Inductor for the high frequencies section.
I will post some pics and the schematic.
I will be glad for some help boys!!

Nacho

 

[Piscolabis]

This is the schematic,

Somebody help me!!

Nacho

 

[Niketouille]

Hi,
Never seen any info on the inductor. You would better do some math to figure out the value. The frequency response are available from a UA bulletin.
Cheers

 

[Piscolabis]

Thanks for your help.
Now I have to find the formula to calculate the values of the inductors to obtain 5kHZ and 10kHZ frequency curve.
You can see it in this link http://www.uaudio.com/webzine/2005/june/graphics/analog-obsession/508A-response-curves.jpg

Somebody?

 

[pucho812]

wait a minute doesn't the 1108 run of a single 24V?  are you planning to convert it to run off a bi-polar supply like used in the 500 series?

anyway this will help you figure out your inductor value

http://www.sengpielaudio.com/calculator-XLC.htm

 

[shabtek]

is there an output transformer that will fit in a single module width;

 

[CJ]

yes, how many do you need my brethren? 

here is one of many online LC calcs>

http://www.deephaven.co.uk/lc.html

now to get the same Q, that will take more math,

 

[Piscolabis]

wait a minute doesn't the 1108 run of a single 24V?  are you planning to convert it to run off a bi-polar supply like used in the 500 series?

anyway this will help you figure out your inductor value

http://www.sengpielaudio.com/calculator-XLC.htm

I am thinking to take +24 from the 51x rack

I have this values 45mh,45mh,15mh,12mh,11mh,4mh for each point thanks to this calculator http://ncalculators.com/electronics/rlc-circuit-frequency-calculator.htm
a total of 45mh

is there an output transformer that will fit in a single module width;

Which transformer?

Thanks to everybody
Nacho

 

[pucho812]

The output transformer. CM-96731... might be too big to fit in one slot of 51X

 

[Piscolabis]

The output transformer. CM-96731... might be too big to fit in one slot of 51X

I know, I will use Ea-5002

 

[dmp]

The EA-5002 will fit in a single rack. I built 4 channels of 1108 in 500 series using O-2 on input.
Are you sure about the inductor calcs? If I recall correctly, the 508 is inserted into the feedback loop of the 1108, in parallel with R20.
So anything the EQ boosts is subtracted from the overall response.

 

[Whoops]

Hi Psicolabis,
did you ever made any progress in this project I will build an 1108 soon and was thinking in trying to add an 508 eq also

Thanks