Poor Man's Pultec EQP1-A Build Support Thread

[johnnyscotch]

Thanks Ian,

I guess the 240v thing threw me. I'm still putting it all together in my head.

cheers
Eric

Hey everyone, I'm building a 2 ch version with Ian's power supply board.

Will this work for the torroid: http://www.antekinc.com/details.php?p=637

It will be a US build (115v, etc...)

You really need one with a 240V secondary so this one would probably be better:

http://www.antekinc.com/details.php?p=638

Edit: or even this one which is in stock at present. The HT will be lower because of the 200V secondary but it should be sufficient for a pair of channels.

http://www.antekinc.com/details.php?p=603


Cheers

Ian

 

[johnnyscotch]

OK, Sorry in advance.

I know this has been asked to death, but I just went through the whole thread again and I can't find a definitive answer for 2 questions:

1) Which pots need to be Log and which Lin? The diagrams, schematic, and information all seem to be at odds with each other.

2) Has anyone made up a parts list of the caps to use with US available pots (50K, etc...)?? I've downloaded and tried altering the available xcl files and I can't get them to work........
If anyone has got them to work, would you mind posting a pdf of the results?

cheers all
Eric

 

[ruffrecords]

OK, Sorry in advance.

I know this has been asked to death, but I just went through the whole thread again and I can't find a definitive answer for 2 questions:

1) Which pots need to be Log and which Lin? The diagrams, schematic, and information all seem to be at odds with each other.

The hi pots are Lin and the lo pots are Log.

2) Has anyone made up a parts list of the caps to use with US available pots (50K, etc...)?? I've downloaded and tried altering the available xcl files and I can't get them to work........

There is only a 6% difference between the nominal UK and US types which is little more than the tolerances of the capacitors you will most likely use. When you add to his the fact that the tolerance on the value of most pots is at least 10% and often 20% then you might just as well use that same values of capacitors for both.


Edit, I have run the spreadsheet with US pot values and attached the results. You need to change the file extension to .xls.

Cheers

Ian

 

[johnnyscotch]

Thanks Ian, That's great,

 

[atticmike]

guys, what sets this build apart from the manley pultec?

also, would you help me figure out to alter the FREQ bands? like going 60, 70 and 120 in the lower register?

 

[ruffrecords]

guys, what sets this build apart from the manley pultec?

It's like 100 times cheaper.

also, would you help me figure out to alter the FREQ bands? like going 60, 70 and 120 in the lower register?

There's a spreadsheet in the documentation that let's you do this - check out the first post for links.

Cheers

Ian

 

[atticmike]

guys, what sets this build apart from the manley pultec?

It's like 100 times cheaper.

also, would you help me figure out to alter the FREQ bands? like going 60, 70 and 120 in the lower register?

There's a spreadsheet in the documentation that let's you do this - check out the first post for links.

Cheers

Ian

Alright.

Got a couple of questions left:

1. this one can by tube gain staged like the manley right?
2. which transformers would I have to get in order to be the closest to the manley as possible?
3. what will I end up spending for a single channel unit?
4. can i use specific greyhill instead of those mouser plastic towers?

Mike

 

[ruffrecords]

Alright.

Got a couple of questions left:

1. this one can by tube gain staged like the manley right?

Yes it can. I have designed a poor man's tube gain make up stage for this project.

http://www.groupdiy.com/index.php?topic=43973.0

2. which transformers would I have to get in order to be the closest to the manley as possible?

The Manley only has one transformer - at the input. I know David Manley prefers Lundhall transformers so I suggest you use one of their 10K:10K input transformers at the input.

3. what will I end up spending for a single channel unit?
4. can i use specific greyhill instead of those mouser plastic towers?

Yes, you can use Grayhill switches if you wish but they will not fit the PCBs. If you want to use Grayhill switches then you will probably be better off using the PCB I designed for them. This PCB has the advantages that it simplifies a lot of the wiring, includes space for an HF inductor so you get the same bell response as the original, and it also includes a mid boost/cut section which is based on the Pultec MEQ5.

Excluding the variable items like enclosure, gain make up amp, transformer and power supply, the approximate costs per channel are:

1. Original design with low cost switches and no inductor will cost about 18 GBP

2. Original design with external Grayhill switches will cost about 45GBP

3. 3 band design with two inductors and three Grayhill switches on a single PCB will cost about 120GBP. About half this cost is for the two inductors and the third Grayhill  switch.

Cheers

Ian

 

[atticmike]

Alright.

Got a couple of questions left:

1. this one can by tube gain staged like the manley right?

Yes it can. I have designed a poor man's tube gain make up stage for this project.

http://www.groupdiy.com/index.php?topic=43973.0

2. which transformers would I have to get in order to be the closest to the manley as possible?

The Manley only has one transformer - at the input. I know David Manley prefers Lundhall transformers so I suggest you use one of their 10K:10K input transformers at the input.

3. what will I end up spending for a single channel unit?
4. can i use specific greyhill instead of those mouser plastic towers?

Yes, you can use Grayhill switches if you wish but they will not fit the PCBs. If you want to use Grayhill switches then you will probably be better off using the PCB I designed for them. This PCB has the advantages that it simplifies a lot of the wiring, includes space for an HF inductor so you get the same bell response as the original, and it also includes a mid boost/cut section which is based on the Pultec MEQ5.

Excluding the variable items like enclosure, gain make up amp, transformer and power supply, the approximate costs per channel are:

1. Original design with low cost switches and no inductor will cost about 18 GBP

2. Original design with external Grayhill switches will cost about 45GBP

3. 3 band design with two inductors and three Grayhill switches on a single PCB will cost about 120GBP. About half this cost is for the two inductors and the third Grayhill  switch.

Cheers

Ian

great, who is offering all the boards for the project?

 

[kante1603]

Hello Mike,

Ian himself offers them in the white market:

http://www.groupdiy.com/index.php?topic=48986.0

Udo

 

[atticmike]

Hello Mike,

Ian himself offers them in the white market:

http://www.groupdiy.com/index.php?topic=48986.0

Udo

ah great,

also found some great guts pics of the manley pultec:

looks like the manley has also tube make up gain and not DOA.

 

[atticmike]

that build looks quite close to the manley:

http://www.groupdiy.com/index.php?topic=32973.0

do you offer all the boards for that?

since he also has those separate boards he connects the pots to instead of having them hanging on the pot.

 

[ruffrecords]

that build looks quite close to the manley:

http://www.groupdiy.com/index.php?topic=32973.0

do you offer all the boards for that?

That's a completely different project. It is pretty much a clone of the EQP1A. I am not sure where you would get the PCBs.

Cheers

Ian

 

[atticmike]

that build looks quite close to the manley:

http://www.groupdiy.com/index.php?topic=32973.0

do you offer all the boards for that?

That's a completely different project. It is pretty much a clone of the EQP1A. I am not sure where you would get the PCBs.

Cheers

Ian

Alright.

But that is actually what I was looking for and what you I supposed referred to as well? Having the caps sit on a separate board and connecting them to the pots so that I can use grey hills. The same way manley's done that?

Plus he's got the same bands used in the manley not like the EQP1.

 

[ruffrecords]

Alright.

But that is actually what I was looking for and what you I supposed referred to as well? Having the caps sit on a separate board and connecting them to the pots so that I can use grey hills. The same way manley's done that?

Plus he's got the same bands used in the Manley not like the EQP1.

The Poor Man's EQP1A is designed to be low cost. So it omits the inductor in the original design, uses cheap switches and, with simple op-amp input buffer and gain make up amps, it can be made very cheaply. This is all explained in the orignal thread here:

http://www.groupdiy.com/index.php?topic=43859.0

There are plenty of Pultec EQP1A clone projects but the poor man's EQP1A is not one of them.

In this thread I am happy to discuss building the poor man's EQP1A and how it can be modified to suit your needs and I have given you three options for this earlier.

If you want to talk about EQP1A clones then you need to ask in the appropriate threads.

Cheers

Ian

 

[TimS]

Since you seem to be so dead set on having something that is exactly like a Manley, I would strongly recommend that you just go ahead and get a Manley. Ian has been extremely generous in putting this project together and in freely lending his assistance to people who are interested in building it, and your constant barrage of questions on multiple threads on replicating a Manley in every minute detail is really quite annoying and not what this forum is about. There is a ton of useful info on this forum and some really great people who are incredibly generous with their knowledge, but it's not fair to abuse their willingness to help - especially when you do so in what quite frankly comes off as a rude and demanding manner.

 

[ruffrecords]

and your constant barrage of questions on multiple threads on replicating a Manley in every minute detail is really quite annoying and not what this forum is about.

If that is what he wants to do then the sensible thing would be to start his own thread on that topic in The Lab.

Cheers

Ian

 

[johnnyscotch]

Ian/or Anyone

The BOM says 220uF 400v for the PS board, but the board itself is labeled 470uF.

Also, the BOM calls for 1N4007, but the board is labeled 1N5408.

Which is correct?
This is for a US build

cheers!
Eric

 

[wave]

Hi Eric,
If you bought the PSU board from Ian, it's labelled with 470µF caps and 1N5408 diodes because the PSU board was originally manufactured for a different project that Ian made.
The layout and form factor of the board can be used for the PMEQP-1A. When you have boards made, there is an additional charge for new silkscreen tooling if you want to change something on the screen.

That being said, you want to use the values from the BOM (220µF, and 1N4007 diodes)

Dave

 

[ruffrecords]

Hi Eric,
If you bought the PSU board from Ian, it's labelled with 470µF caps and 1N5408 diodes because the PSU board was originally manufactured for a different project that Ian made.
The layout and form factor of the board can be used for the PMEQP-1A. When you have boards made, there is an additional charge for new silkscreen tooling if you want to change something on the screen.

That being said, you want to use the values from the BOM (220µF, and 1N4007 diodes)

Dave

Exactly right. With the bigger diodes and caps, this supply was used for a 6 into 2 mixer using 18 tubes drawing over 100mA. For a couple of poor man's tube gain make boards drawing about 10mA the 1N4007 and 220uF values are more than adequate.

Cheers

Ian