erikb1971

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #60 on: November 17, 2011, 12:59:45 PM »
well.. considering the broad freq spectrum of the mid section... it crossed my mind yes...
We are getting way past relatively easy


ruffrecords

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #61 on: November 17, 2011, 03:46:31 PM »
well.. considering the broad freq spectrum of the mid section... it crossed my mind yes...

I have to confess I am a little uneasy about the broad range of the mid section combined with simultaneous mid boost and cut. The reason is that the original poor man's Pultec design tries to ensure that the load on the input transformer is never much less than 10K. With the mid overlapping some of the high boost  and  hi cut frequencies then with simultaneous mid boost/cut and hi boost/cut at the same frequency this load could drop below 5K which the transformer will reflect to the input. Now that is not going to be a problem for most modern gear driving this circuit but some of my tube circuits would struggle.

From the circuit point of view I see no reason not to build it with separate mid boost and mid  cut circuits (though you will need two inductors). I guess configured that way it would make a rather interesting 4 band semi-parametric EQ. If you do decide to do it, it might be interesting to use a different inductor for the cut in order to broaden the Q somewhat. If you use a larger inductor for the mid cut you can get to some quite interesting low frequencies. I thought perhaps 150Hz and 180Hz high Q mid cut would be useful for hum elimination for example.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

erikb1971

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #62 on: November 17, 2011, 03:58:40 PM »
hmmm sounds interesting... I would need some help from you however... but I put myself for 6 mid boards on the list... So I am ready for that!
We are getting way past relatively easy

ruffrecords

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #63 on: November 17, 2011, 05:17:38 PM »
hmmm sounds interesting... I would need some help from you however... but I put myself for 6 mid boards on the list... So I am ready for that!

No problem. Happy to help.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

erikb1971

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #64 on: November 17, 2011, 05:21:47 PM »
Happy to hear that! BTW, I think you can start designing the dedicated mid boards... 39 orders so far :-)
We are getting way past relatively easy

baadc0de

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #65 on: November 18, 2011, 07:12:44 AM »
Well, it's extra hard to squeeze all the items for 4 channel in 3U in there and I still need to add the on/off switch, an indicator light / LED, some switches to put turn the mids off etc..

Also this is way over the "poorman" moniker because I thought maybe I could use some jensens as I/O.. and use almost exclusively styros for caps.

baadc0de

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #66 on: November 18, 2011, 07:43:32 AM »
And a 4U option that my girlfriend likes much better :P

ruffrecords

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #67 on: November 18, 2011, 07:51:17 AM »
And a 4U option that my girlfriend likes much better :P

That is certainly a beast of an EQ. I am not sure the mid PCB will fit to your front panel at present because it looks like being 3.5 inches wide. Check out the thread on the mid PCB in the Blacj Market for more details - and of course feel free to comment too.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

baadc0de

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #68 on: November 18, 2011, 08:02:54 AM »
Yeah, all thanks goes to you Ian for making it available.. none of this would be happening if not for your efforts and I really appreciate it! It really looks like a beast of an EQ and with your nice 6CG7 makeup stage, styro caps, jensen trafos.. it's bound to sound awesome. Can't wait to get this crunching on some material. I'm thinking this would also be useful to EQ quadraphonic masters hmm :) since I also have two straight ahead pultec clones, I could pultec-ize a 5.1 mastering chain lol :)

That said, I'll be looking to mount the components on the back of the PCB and use the shallowest possible pots and switches so they don't touch the PCB. We'll see how that goes and if nothing else I could always offboard the switches and just mount the mid PCBs to the case not the front panel. I have a big roll of 6-wire ribbon cable and I'm not afraid to use it haha :) though I'd prefer if it doesn't come to this. I see maybe the inductor wouldn't work if I mounted it on the back of the PCB, so I guess it's either a different (rotated) inductor or offboarding it or offboarding the swtich, whatever works..

ruffrecords

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #69 on: November 18, 2011, 09:14:16 AM »
I see maybe the inductor wouldn't work if I mounted it on the back of the PCB, so I guess it's either a different (rotated) inductor or offboarding it or offboarding the swtich, whatever works..

Actually, after posting about the size of the new PCB I also wondered if we could fit the inductor on the back behind the switch. I think that provided you fit the switch first and crop its tags quote short it should be possible to then fit the inductor on the back.I'll give it some thought.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


erikb1971

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #70 on: November 19, 2011, 05:47:18 PM »
Wow! I agree with the girlfriend! Could you post it in the mid feeler thread for inspiration?
We are getting way past relatively easy

baadc0de

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #71 on: November 23, 2011, 04:26:22 AM »
For a 4U Poshman, which I define as 4 channels of dual mids + hi / low, please find attached a FPD file. You will have to add on/off power switches and any LED indicators if you wish, as well as your logo etc.. this is kind of like a template for those who are interested in such a panel. Enjoy :)

IMPORTANT NOTE: the forum software does not allow upload of an FPD file. Download this file and change its extension to FPD instead of PDF!

ruffrecords

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #72 on: November 23, 2011, 05:07:57 AM »
For a 4U Poshman, which I define as 4 channels of dual mids + hi / low, please find attached a FPD file. You will have to add on/off power switches and any LED indicators if you wish, as well as your logo etc.. this is kind of like a template for those who are interested in such a panel. Enjoy :)


That is an incredibly detailed panel. I notice that each scale is a .plt file. I have used FPD a bit but never to create something that intricate. Can you say a little about how you create these .plt files? I was just wondering if we should think about setting up a repository of such files for everyone to use.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

erikb1971

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #73 on: November 23, 2011, 05:25:24 AM »
can't open or download the file.... grrr.. could you email it to erikb1971 at gmail dot com?
We are getting way past relatively easy

ruffrecords

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #74 on: November 23, 2011, 06:57:03 AM »
can't open or download the file.... grrr.. could you email it to erikb1971 at gmail dot com?

Done,

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

erikb1971

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #75 on: November 23, 2011, 08:30:35 AM »
TNX.. and it IS looking good! Would you mind if I rebuild it to my 3u stereo version?
We are getting way past relatively easy

ruffrecords

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #76 on: November 23, 2011, 10:06:55 AM »
TNX.. and it IS looking good! Would you mind if I rebuild it to my 3u stereo version?

I don't mind and I think baadc0de intended to donate it to the group.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

ej_whyte

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #77 on: November 23, 2011, 12:15:54 PM »
For a 4U Poshman, which I define as 4 channels of dual mids + hi / low, please find attached a FPD file. You will have to add on/off power switches and any LED indicators if you wish, as well as your logo etc.. this is kind of like a template for those who are interested in such a panel. Enjoy :)


That is an incredibly detailed panel. I notice that each scale is a .plt file. I have used FPD a bit but never to create something that intricate. Can you say a little about how you create these .plt files? I was just wondering if we should think about setting up a repository of such files for everyone to use.

Cheers

Ian


http://www.frontpanelexpress.com/fileadmin/pdf/tips_tricks/jskala_english.jar

Very useful  :) Although it looks a bit confusing and usually takes a couple of attempts to get it right, have a play and you will soon work it out, shame there is no preview box though.

Create a file, import HPGL in to FPD and then it gives you the colour & thickness options. Make sure you set the origin to follow the origin of the imported HPGL, makes aligning the scale much easier.

Cheers
« Last Edit: November 23, 2011, 12:25:03 PM by ej_whyte »

erikb1971

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #78 on: November 23, 2011, 12:20:31 PM »
first sketch of stereo 2U posh men's eq... love the way you can switch the mid sections off or off and how there is a double boost mid, but no cut..... sloppy work, better later!:-)
updated.. that is better
« Last Edit: November 23, 2011, 04:15:59 PM by erikb1971 »
We are getting way past relatively easy

ruffrecords

Re: any ideas for adding a sweepable mid to the Poor Man's Pultec EQP1-A ?
« Reply #79 on: November 23, 2011, 04:19:55 PM »
first sketch of stereo 2U posh men's eq... love the way you can switch the mid sections off or off and how there is a double boost mid, but no cut..... sloppy work, better later!:-)

I am not sure about the double boost you have there. The idea was you could have a single frequency control that could be switched to either boost or cut OR you could have two frequency controls, one assigned to cut and the other to boost. Although you could have two mid boosts you would have to be very careful how you used it. If you set the boosts to the same frequency you would not get double the dB boost. The boosts are quite wide so you might well get two separate boosts where the frequencies are an octave apart for example but much closer and they will start to interact. I am not saying don't do but just be careful if you do. An interesting alternative might be to look at a pair of mid boost/cuts with no-overlapping frequencies using two different inductors. That way the lower end could be extended to the region of 150Hz and include frequencies like 150Hz and 180Hz which are useful for removing hum. So one control could cover from 150Hz to 1.5Khz and the second from 1.6KHz to 16KHz for example.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


 

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