Poor Man's Pultec EQP1-A

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buildafriend said:
what does the inductor usually run you?

The inductor was put in as a bit of an after thought simply because there was space on the PCB for a small one and somebody asked if I would include it on the layout. It just allows a small inductor to be used at one frequency setting only. You don't need to fit it and you can just  short it out.

If you look half way down this page:

http://www.groupdiy.com/index.php?topic=43859.60

you will see what I said about possible inductor values.

Cheers

Ian
 
Hi Ian,

I requested 2 board sets on the second run you posted.  I haven't heard anything about that order or received a PM.  I'm ready to pay for them just not sure what and to who. 

Sorry if this post is in the wrong thread.

Michael
 
fazer said:
Hi Ian,

I requested 2 board sets on the second run you posted.   I haven't heard anything about that order or received a PM.   I'm ready to pay for them just not sure what and to who.   

Sorry if this post is in the wrong thread.

Michael

There's a thread for this in the Black Market. I placed the order today and asked for payment in that thread. You are on the list in that thread. Check it out here:

http://www.groupdiy.com/index.php?topic=44025.40

Cheers

Ian
 
Holger said:
I've assembled one channel today using the JLM Dingo as make up stage (with a JLM high voltage OpAmp) 
and two old Altec transformers. I like what I hear.

Well done! I think you must be the first person, apart from me, to get a channel working. Glad you like it.

Cheers

Ian
 
This picture was never intended to get published, so please excuse the crappy photo.
The reason I used the term 'assembled' earlier is obvious...  ;) I should have used the term 'tinkered'.
This is still in the experimentation phase.

I've built only one half (balancing part) of the Dingo. The input signal goes to the terminal strip to use the relay functionality. After that I've used the molex connector at the phase reverse jumper point to connect the input transformer.


dingo.jpg
 
Hank Dussen said:
How well does it work for frequencies above 16K?
Do these only work with an additional inductor?

I expect it will work fine for hi boost/cut frequencies up to 30KHz without any inductor, as much as anything because the switch frequency is where the final shelving occurs but to reach this the circuit has to start boosting or cutting at a frequency much lower than this. The inductor was only added as an afterthought because someone asked for it and there was space for it on the PCB.

If you look at the capacitor calculator spreadsheet you will see I have included 20KHz and 30KHz frequencies. Note that the boost cap is becoming rather small (about 1500pF at 30KHz) so stray capacitances, especially in screened cables, may begin to affect the response. You are welcome to experiment with higher shelving frequencies but I would suggest 30KHz as a useful upper limit.

Cheers

Ian
 

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