GroupDIY

Project Specific Discussions => Filters/Equalizers => Topic started by: Gustav on May 28, 2015, 01:44:05 PM

Title: Build Thread:PQD2
Post by: Gustav on May 28, 2015, 01:44:05 PM
This project was based off Gyraf's PeQ DIY version. I just doubled the amount of channels run off the same supply and controlled everything using PCB mount/off the shelf Lorlins so it would be a breeze to build it.

https://www.pcbgrinder.com/produktside/pq2 (https://www.pcbgrinder.com/produktside/pq2)

Ill be happy to help with any build issues  - if I can!?

Gustav
Title: Re: Build Thread:PQD2
Post by: hymere on June 24, 2015, 08:49:37 AM
Hi Gustav, i would originaly make a Heater, to use it in tube DI. But i told me, that's  the output stage of the PQD2!!
If i make a full PQD2,  can i use it in DI application? I can add a other input after the EQ section or use it with the original input??
Because the output transfo symmetrizes the signal, is'nt it?

Thank's and sorry for my English..
Title: Re: Build Thread:PQD2
Post by: Gustav on June 24, 2015, 09:26:12 AM
Hi Gustav, i would originaly make a Heater, to use it in tube DI. But i told me, that's  the output stage of the PQD2!!
If i make a full PQD2,  can i use it in DI application? I can add a other input after the EQ section or use it with the original input??
Because the output transfo symmetrizes the signal, is'nt it?

Thank's and sorry for my English..

Hi hymere.

The tube gainstage may be the same, but then again, its not. There were subtle changes made to the HEATER to accommodate the instrument level inputs. Also, we are going straight to the "heart" of the gain stage with the HEATER circuit. This will not be the case  if you try to use the PQD2 in the same type of application, and it may render the input attenuation a mess if you try it (I haven't tried it)

I would build the heater if I needed a DI/line driver/gainstage for a summing box? an extra 20dB of gain for something etc.
I would build the PQD2 if I needed a stereo, passive EQ with detented controls and a great sounding tube, gain stage :)

Gustav
Title: Re: Build Thread:PQD2
Post by: drivebystudios on July 20, 2015, 10:50:11 PM
How is everyone finding the mastering version?
Are the 12 step increments ok??
Title: Re: Build Thread:PQD2
Post by: Gustav on July 21, 2015, 03:06:52 AM
How is everyone finding the mastering version?
Are the 12 step increments ok??

11 step...

If you have something specific you'd like to know, I would be happy to try and help. Ill stay away from the more subjective evaluation of it :)

Gustav
Title: Re: Build Thread:PQD2
Post by: madsimilius on July 24, 2015, 09:50:33 AM
Today i started on a kit i resently bought from Gustav.
The pqd2 is my first real diy project except moding and car electronics. 
I won't get shocked and set fire to my home i promise :P I'll get someone to look over it before i fire it up.
Until now i have managed to sort out where every thing goes as the pcb is marked well, except the resistors that lies around the pots. They are marked a1,a2,a3,a4,a5,a6,a7,a8,a9,a10 around one pot and b1,b2,b3,b4,b5,b6,b7,b8,b9,b10 around the next, and so on.  how do i understand what resistor goes where here? 
Title: Re: Build Thread:PQD2
Post by: Gustav on July 27, 2015, 03:02:51 PM
Today i started on a kit i resently bought from Gustav.
The pqd2 is my first real diy project except moding and car electronics. 
I won't get shocked and set fire to my home i promise :P I'll get someone to look over it before i fire it up.
Until now i have managed to sort out where every thing goes as the pcb is marked well, except the resistors that lies around the pots. They are marked a1,a2,a3,a4,a5,a6,a7,a8,a9,a10 around one pot and b1,b2,b3,b4,b5,b6,b7,b8,b9,b10 around the next, and so on.  how do i understand what resistor goes where here?

Here you go :) (Should also be on the kit page. If you dont see it, hit refresh).

pcbgrinder.com/download/PQD2/PQD2switches-kit.xlsx

Gustav
Title: Re: Build Thread:PQD2
Post by: madsimilius on July 29, 2015, 02:43:39 PM
I didn't see it actualy :P Maby because it was under the project discussion link?
Anyhow thank you !
Title: Re: Build Thread:PQD2
Post by: madsimilius on July 31, 2015, 05:06:31 PM
The pcbs
Title: Re: Build Thread:PQD2
Post by: madsimilius on July 31, 2015, 05:08:49 PM
Temporary front panel made with an angle grinder and a drill .
Title: Re: Build Thread:PQD2
Post by: madsimilius on August 06, 2015, 03:21:19 PM
I need help with wiring my toroidal, fuse, iec, power switch and ground. (230v)

On the toroidal it says: Prime 1 orange - yellow 0-115v, Prime 2 orange - yellow 0-115v,
                                                   Sec 1 white - black 230V/35mA,  Sec 2 blue - green 9V2A

One of the orange and one of the yellow wires have a piece of black heat shrink tubing on them. (for marking i guess)

I guess the blue and green and the black and white goes to the pcb. on the pcb it only says 250vac 1 and 2 and 9vac 1 and 2, how do i know which goes to 1 and which goes to 2?
Do i wire anything  from the ground point on the pcb ?chassie?  and do i wire anything to the 6.3v ?
Actually if anyone could explain to me how to wire the iec, toroidal, fuse, power switch and ground so that i'm sure  it would help me alot !
Title: Re: Build Thread:PQD2
Post by: Gustav on August 07, 2015, 12:42:37 AM
I need help with wiring my toroidal, fuse, iec, power switch and ground. (230v)

On the toroidal it says: Prime 1 orange - yellow 0-115v, Prime 2 orange - yellow 0-115v,
                                                   Sec 1 white - black 230V/35mA,  Sec 2 blue - green 9V2A

One of the orange and one of the yellow wires have a piece of black heat shrink tubing on them. (for marking i guess)

The primaries are orange/yellow pairs. One pair has the black tape marking, the other doesnt. You should wire them in series for 220/230V mains. (Tip, when in doubt, you could have used your meter to see which wires are pairs)

I guess the blue and green and the black and white goes to the pcb. on the pcb it only says 250vac 1 and 2 and 9vac 1 and 2, how do i know which goes to 1 and which goes to 2?

Does it matter whats 1 and whats 2 when its AC?

Do i wire anything  from the ground point on the pcb ?chassie?  and do i wire anything to the 6.3v ?
Actually if anyone could explain to me how to wire the iec, toroidal, fuse, power switch and ground so that i'm sure  it would help me alot !

The reason why I didn't post a wire guide for this for tube project is because I think its dangerous to mess with these high voltage projects without knowing something as basic  as mains/fuse wiring (I also stated this on the site). I would recommend you to find someone local to help you out in person.  Things can get confused in writing, and I dont want to see you get hurt.

I mean this is the nicest way with all care for your safety: I think youre nuts for building this. Be really carefull, measure everything twice, make sure the supply caps are drained when you work on it etc.

Gustav

Title: Re: Build Thread:PQD2
Post by: guilds100 on August 07, 2015, 07:13:21 AM
Im starting to put the rotary switches into my pqd2 when I noticed the low freq, high freq, and attenuation switches have an extra center hole. Are these 1x12 like the bill of materials listed or are they 2x6?
Title: Re: Build Thread:PQD2
Post by: Gustav on August 07, 2015, 07:35:08 AM
Im starting to put the rotary switches into my pqd2 when I noticed the low freq, high freq, and attenuation switches have an extra center hole. Are these 1x12 like the bill of materials listed or are they 2x6?

The frequencies are 2x6.

Updated the BOM

Gustav
Title: Re: Build Thread:PQD2
Post by: bacbacou on August 07, 2015, 08:44:15 AM
hello,
I am going  to build to a PQD2, I see on the BOM  :
"16  pcs 1x12     lorlin     switch"

could you confirm if these one's are ok :

http://www.mouser.fr/Search/ProductDetail.aspx?R=CK1059virtualkey12200000virtualkey10SM159 (http://www.mouser.fr/Search/ProductDetail.aspx?R=CK1059virtualkey12200000virtualkey10SM159)

and, how to use your switch calculator ? I open it, see two examples with 10K and 100K log, but what about 1K/2,2K ans 10K lin ?


Richard
Title: Re: Build Thread:PQD2
Post by: Gustav on August 07, 2015, 09:28:34 AM
hello,
I am going  to build to a PQD2, I see on the BOM  :
"16  pcs 1x12     lorlin     switch"

Check the post just above yours re:BOM correction.

could you confirm if these one's are ok :

http://www.mouser.fr/Search/ProductDetail.aspx?R=CK1059virtualkey12200000virtualkey10SM159 (http://www.mouser.fr/Search/ProductDetail.aspx?R=CK1059virtualkey12200000virtualkey10SM159)

I can never "confirm" (I make mistakes myself when buying parts, and some parts are described in confusing ways at some vendors to me), but I can share a guess.

I am not sure why the "terminal" style is written as "terminal". I would assume that means the switches have solder eyes/are not PCB mountable, but in mounting style, it says through hole, and the part name has PCB in it.

So - not 100% sure.

D-shaft wouldn't be my first choice either, but thats more of a mechanical issue.

and, how to use your switch calculator ? I open it, see two examples with 10K and 100K log, but what about 1K/2,2K ans 10K lin ?


Richard

The linear pots are linear, so the values going around the switch are linear (They have their own fields in the bottom of the switch sheet. Hope it makes sense).

Theres no "correct way" to use the calculator. I just did the PDF to make sure the values add up to the necessary total if you change some values around. You may want to switch it up a little to create a graph you like better etc. 

Just use the values it opens up with if you're in doubt.

Hope that helps :)

Gustav
Title: Re: Build Thread:PQD2
Post by: bacbacou on August 08, 2015, 02:53:42 AM
thank you Gustav !
Title: Re: Build Thread:PQD2
Post by: Eddy.L on September 21, 2015, 11:15:53 AM
HI !
I bought a light for the on/off which works with 6.3V can I wire it between the 6.3V and Ground spots on the pcb ?
Will there be enough Ampers for the two tubes ? And I changed the value of the 1.8K resistor for 1.9K and I'm closer to 6.3V now is it okay ? And last question how do I chose between the value that you gave for the drop resistor ?

Thank you !
Title: Re: Build Thread:PQD2
Post by: Gustav on September 21, 2015, 12:08:07 PM
HI !
I bought a light for the on/off which works with 6.3V can I wire it between the 6.3V and Ground spots on the pcb ?
Will there be enough Ampers for the two tubes ? And I changed the value of the 1.8K resistor for 1.9K and I'm closer to 6.3V now is it okay ? And last question how do I chose between the value that you gave for the drop resistor ?

Thank you !

I would draw the 6.3V from the secondary on the trafo with a drop resistor. The lamp will work with your method, though.

1K9 is fine, 1K8 was fine as well.

The value for the drop resistor - try one, check the voltage, adjust up or down in size.

Hope that helps :)

Gustav


Title: Re: Build Thread:PQD2
Post by: Eddy.L on September 22, 2015, 04:08:46 AM
Ok thank you ! I failed calculating the correct drop voltage resistor I have 6.3V to the lamp but don't have enough Ampers... But I know why.... And I don't understand how the drop resistor is related to the 6.3V  that seems to be the output of the LM317 ? But I don't know if you have the time to explain me that.

Thank you !

PS : last question... In the case that I bought there was already a switch with the IE Socket and I have wired it, is it a problem if wire a second switch  at the primary thoroidal transformer ?
Title: Re: Build Thread:PQD2
Post by: Gustav on September 22, 2015, 05:07:36 AM
Ok thank you ! I failed calculating the correct drop voltage resistor I have 6.3V to the lamp but don't have enough Ampers... But I know why.... And I don't understand how the drop resistor is related to the 6.3V  that seems to be the output of the LM317 ? But I don't know if you have the time to explain me that.

I am sorry, but I am not sure what youre asking here, so Ill freestyle it.

IF you are drawing the connection from the 6.3V, you dont need a drop resistor to power a 6.3V LED package (You mentioned the desire to use such an LED in your previous post).  You only need the drop resistor if you are drawing from the 9V secondary, which I would recommend.

You dont have enough amps, and you know why!? Could you rephrase this problem? I doubt you have a lack of available current, which is what it reads like..

If you answer the question "How are you trying to connect the LED?", it may clear it up

PS : last question... In the case that I bought there was already a switch with the IE Socket and I have wired it, is it a problem if wire a second switch  at the primary thoroidal transformer ?

I dont see why, other than having two switches doing the same thing. 

Gustav
Title: Re: Build Thread:PQD2
Post by: Eddy.L on September 22, 2015, 08:05:49 AM
Sorry my post was very confused... So I'll start again.

I follow your advice for the lamp. I wired it to the 9V secondary this is why I was talking about a drop resistor (and my problem of current might because I calculated the value of the resistor in order to have 0,015A instead of 0,15A).

And the thing that I don't understand is how the 2W drop resistor which is named R120 on the scheme have an effect on the 6.3V which goes to the tubes ? But if you don't have the time to explain it's okay !

Thank you again for your help !

PS : the lamp is this kind of lamp it's not a led https://www.banzaimusic.com/47-Light-Bulb.html
Title: Re: Build Thread:PQD2
Post by: Gustav on September 22, 2015, 10:13:16 AM
Sorry my post was very confused... So I'll start again.

I follow your advice for the lamp. I wired it to the 9V secondary this is why I was talking about a drop resistor (and my problem of current might because I calculated the value of the resistor in order to have 0,015A instead of 0,15A).


Amount of voltage you need to drop = 9-6,3 = 2,7V (Measure real life voltage output from the secondary)

V = R x I

2,7 = 0,15 x R

Isolate R to get the value of the resistor you need in ohms.


And the thing that I don't understand is how the 2W drop resistor which is named R120 on the scheme have an effect on the 6.3V which goes to the tubes ?

It shouldn't. Not unless theres something wrong. 

Gustav
Title: Re: Build Thread:PQD2
Post by: Eddy.L on September 22, 2015, 10:21:45 AM
And the thing that I don't understand is how the 2W drop resistor which is named R120 on the scheme have an effect on the 6.3V which goes to the tubes ?

It shouldn't. Not unless theres something wrong. 


So I think I didn't understand how to choose the good resistor value for R120 ? Which voltage should I check ?
Title: Re: Build Thread:PQD2
Post by: p0ulp on September 22, 2015, 11:16:18 AM
Hello, I m currently making my order for this project but can't find inductance that looks like the one on the pcb (they look like resistor at leat in format) but there is no spec or type of package specified.
I someone could post picture of his unit where the inductance are shown that would maybe help me :) or any mouser/rs/digikey reference ?

I ve only found smaller value that could fit the PCB

thank you
Title: Re: Build Thread:PQD2
Post by: Gustav on September 22, 2015, 11:31:36 AM
Hello, I m currently making my order for this project but can't find inductance that looks like the one on the pcb (they look like resistor at leat in format) but there is no spec or type of package specified.
I someone could post picture of his unit where the inductance are shown that would maybe help me :) or any mouser/rs/digikey reference ?

I ve only found smaller value that could fit the PCB

thank you

If you haven't bought the boards yet, I have a package of suitable inductors in the hard candy section of the store..

The shape of the silk screen is not the determining factor here...sorry if thats confusing.

Gustav
Title: Re: Build Thread:PQD2
Post by: Gustav on September 23, 2015, 02:43:16 AM
So I think I didn't understand how to choose the good resistor value for R120 ? Which voltage should I check ?

Are you saying you dont know which voltage the resistor R120 is supposed to drop?  (Im afraid you might even be thinking its related to the hook-up of your light at this point!?).

1. If that is the case, I think you should get help from someone who knows what they are doing to stay safe.

2. See attached picture.


Gustav
Title: Re: Build Thread:PQD2
Post by: Eddy.L on September 23, 2015, 03:15:08 AM
I found it by myself yesterday afternoon looking checking the scheme in fact, I don't know why I understood it was linked to the 6.3V.... Thank you again for your help ! And sorry for my dumb questions...
Title: Re: Build Thread:PQD2
Post by: Gustav on September 23, 2015, 03:37:54 AM
I found it by myself yesterday afternoon looking checking the scheme in fact, I don't know why I understood it was linked to the 6.3V.... Thank you again for your help ! And sorry for my dumb questions...

I dont believe theres such a thing as dumb questions, but...

When I see someone who doesn't know how to follow a trace building a GssL or similar, I see it as a goal to bring him a few steps forward. When I see someone who doesn't know how to follow a clear supply line building a high voltage project, I get the instinct to take him a few steps back.

Its simply a matter of keeping safe while making mistakes :)

Gustav
Title: Re: Build Thread:PQD2
Post by: Patch on September 23, 2015, 04:32:27 AM
Hey Gustav, nice looking project man, I have always gotten my boards from you (apart from my neve) and they've always been top class.

 I've actually been looking to build another Dual G Pultec but this time I wanted to make it stereo 1U with ganged pots and ganged (double deck)  switches. But it seems according to Jakob that with ganged pots can you'll be lucky to get the tracking within 10%, which doesn't sound good at all for stereo tracking.

As this version of the G Pultec only uses switches I was thinking it may be better to use for ganged controls. What do you think to that?

I was also wondering how this circuit differs (apart from PCB layout and switches) to Jakob's G Pultec?

Last question sorry... The optional 'Variable level control', does this boost gain post eq? (i presume it must), is there potential to get a bit of saturation from the valve gain stage into the TRX? Don;t want to get off into the subjective too much (as I know the heavy weights on this forum don;t tend to get into that) but a bit of saturation control for some added colour would be interesting, but perhaps not ideal for this unit. 
Title: Re: Build Thread:PQD2
Post by: Gustav on September 23, 2015, 04:40:25 AM
Ill answer what I feel I can...

I was also wondering how this circuit differs (apart from PCB layout and switches) to Jakob's G Pultec?

It doesnt...


The optional 'Variable level control',

...is on the MS PQ76 I did with no tubes, not this project.

Gustav
Title: Re: Build Thread:PQD2
Post by: Patch on September 23, 2015, 04:46:33 AM
Thanks for the ultra quick response.

I think you may need to update your info on PCB grinder then as it states for this project:

Features

-All controls detented for level matching and recall
-Regulated heater supply for stable operation
-Variable level control available at builders own preference.
 


You didn;t answer the bit on dual gang, although thinking about it I'm guessing of course switches are going to get good tracking right, Pots are more the issue with dual gang tracking....
Title: Re: Build Thread:PQD2
Post by: Gustav on September 23, 2015, 05:00:44 AM

-Variable level control available at builders own preference.


What I mean is the option of varying the level of the EQ boost/cut controls with resistor selection. Ill put it on my to-do list to reword it, as I can see how it can be misread.

For switches, tracking will depend on the resistors you solder into the switch.

Gustav

Title: Re: Build Thread:PQD2
Post by: Patch on September 23, 2015, 05:55:04 AM
Ahhh ok, that makes sense now. Thanks you  :)
Title: Re: Build Thread:PQD2
Post by: Patch on September 23, 2015, 11:05:22 AM

For switches, tracking will depend on the resistors you solder into the switch.

Gustav

Yes of course, but sourcing matching resistors and also having the option to chop and change them to find the 'perfect two' seems a lot safer than these dual gang pots which Jakob says are rarely used in EQs as the tracking is rarely better than 10% (that's a scary number to me).....

Just gotta decide if the steps are going to be to my satisfaction... I guess as you said about the 'variable level' you can tailor the step changes as you wish, so I'm thinking I will go for this PQD2
Title: Re: Build Thread:PQD2
Post by: p0ulp on September 25, 2015, 08:48:22 AM
Hello, I m currently making my order for this project but can't find inductance that looks like the one on the pcb (they look like resistor at leat in format) but there is no spec or type of package specified.
I someone could post picture of his unit where the inductance are shown that would maybe help me :) or any mouser/rs/digikey reference ?

I ve only found smaller value that could fit the PCB

thank you

If you haven't bought the boards yet, I have a package of suitable inductors in the hard candy section of the store..

The shape of the silk screen is not the determining factor here...sorry if thats confusing.

Gustav

That's ok ;) I ve seen the inductor on your store that's still good visual information :)


Title: Re: Build Thread:PQD2
Post by: p0ulp on September 27, 2015, 11:12:30 AM
populating this one ... also :D , and looking for the calculation tools, it only concern the low boost/low cut so I guess its the same calculation for the high boost/cut since it's supposed to act as a 10k log/100k log also ? am I right ? it's indicated A/F for the 100k and B/G for the 10k , so that one is ok I suppose.

My question is about frequency and Q ... is there a tools that we can use to calculate those value without having to compute all the filter information (which I am sure would lead me to error as I m not yet comfortable with it) , a tool like harpo did for the neteq maybe ?

Also may I suggest an "offboard" overlay for the cap value just as a pdf to document the build, the overlay can be a little tricky to read :)

Title: Re: Build Thread:PQD2
Post by: Gustav on September 28, 2015, 12:56:01 AM
populating this one ... also :D , and looking for the calculation tools, it only concern the low boost/low cut so I guess its the same calculation for the high boost/cut since it's supposed to act as a 10k log/100k log also ? am I right ? it's indicated A/F for the 100k and B/G for the 10k , so that one is ok I suppose.

My question is about frequency and Q ... is there a tools that we can use to calculate those value without having to compute all the filter information (which I am sure would lead me to error as I m not yet comfortable with it) , a tool like harpo did for the neteq maybe ?

Also may I suggest an "offboard" overlay for the cap value just as a pdf to document the build, the overlay can be a little tricky to read :)

The only thing the calculator does is make sure the total sum is correct and round the resistor values to the E96 ladder (I have to figure out how to make this into E24 some day). I put in the graphs so you can see the log curves, which I know now was a mistake (and really doesn't make much sense). A lot of people think the goal is to get a linear curve going by changing values around. The high cut and high boost are linear, which is why the table simply states the value to put into each, identical step.

When I do another run, I will change the nominators on the board and put in the "default" values from the sheet. They work out very well, and with pre-fixed values. Tinkering with the values for the sake of tinkering with no real idea what the prefix would've done is not really productive imo.

For the high Q/(bandwidth), it might make sense to experiment if you want to measure exact Q values. Personally, I am not someone who is very discerning when it comes to specific Q values, as long as the switch has a throw to it where I can hear the steps working.

Gustav
Title: Re: Build Thread:PQD2
Post by: Vac11 on September 30, 2015, 02:40:17 AM
Hi Gustav!

1) In BOM are these resistors:

3x470R
2x470K
2x75R
2x1M
2x1K
4x10K
1x1K8
 
Are these standard 1/4W, 1% tol.? How critical are these parts?

2) What exactly is an inscription ""high voltage" on the capacitor specified in BOM? It is sufficient 250V , rather than  400V and higher?

Thanks

MV

Title: Re: Build Thread:PQD2
Post by: Gustav on September 30, 2015, 05:03:46 AM
Hi Gustav!

1) In BOM are these resistors:

3x470R
2x470K
2x75R
2x1M
2x1K
4x10K
1x1K8
 
Are these standard 1/4W, 1% tol.? How critical are these parts?

2) What exactly is an inscription ""high voltage" on the capacitor specified in BOM? It is sufficient 250V , rather than  400V and higher?

Thanks

MV

1/4Watt is fine. I think the 470R could benefit from being 1/2 or 1 watt in tight situations. (I think its 470R, check with the schematic yourself)

HV is just an indicator it should be sufficient for the high voltage rail, wether you're running it at 180 or 250V.

Gustav
Title: Re: Build Thread:PQD2
Post by: p0ulp on October 03, 2015, 03:26:44 AM
populating this one ... also :D , and looking for the calculation tools, it only concern the low boost/low cut so I guess its the same calculation for the high boost/cut since it's supposed to act as a 10k log/100k log also ? am I right ? it's indicated A/F for the 100k and B/G for the 10k , so that one is ok I suppose.

My question is about frequency and Q ... is there a tools that we can use to calculate those value without having to compute all the filter information (which I am sure would lead me to error as I m not yet comfortable with it) , a tool like harpo did for the neteq maybe ?

Also may I suggest an "offboard" overlay for the cap value just as a pdf to document the build, the overlay can be a little tricky to read :)

The only thing the calculator does is make sure the total sum is correct and round the resistor values to the E96 ladder (I have to figure out how to make this into E24 some day). I put in the graphs so you can see the log curves, which I know now was a mistake (and really doesn't make much sense). A lot of people think the goal is to get a linear curve going by changing values around. The high cut and high boost are linear, which is why the table simply states the value to put into each, identical step.

When I do another run, I will change the nominators on the board and put in the "default" values from the sheet. They work out very well, and with pre-fixed values. Tinkering with the values for the sake of tinkering with no real idea what the prefix would've done is not really productive imo.

For the high Q/(bandwidth), it might make sense to experiment if you want to measure exact Q values. Personally, I am not someone who is very discerning when it comes to specific Q values, as long as the switch has a throw to it where I can hear the steps working.

Gustav

I think the same, would like to use the "default" value and if needed change for more personnal, no need to change something until you know why and where to go ...

By the way, where are the "default value" ?

I ve checked your peq1a page and the topic related here to find out but I only get several BOM and reference to buy but no link between overlay and different resistor value.

Also, the schem available on your website is really small, I ve also looked at it to find out but can't zoom in as much as I want.



By
Title: Re: Build Thread:PQD2
Post by: Gustav on October 03, 2015, 04:25:59 AM

I think the same, would like to use the "default" value and if needed change for more personnal, no need to change something until you know why and where to go ...

By the way, where are the "default value" ?

I ve checked your peq1a page and the topic related here to find out but I only get several BOM and reference to buy but no link between overlay and different resistor value.

Also, the schem available on your website is really small, I ve also looked at it to find out but can't zoom in as much as I want.



By

Default values are in the excel file (tip, since its the same values for all 11 slots, its only written once for the linear switches).

If you can't zoom on the schem, one explanation could be that you are not zooming in your PDF reader, but your browser.  The resolution is plenty high, but if I "pinch zoom" on the mousepad on my laptop, everything gets grainy real fast



Gustav
Title: Re: Build Thread:PQD2
Post by: p0ulp on October 03, 2015, 08:54:41 AM
ok that's clear :)
Title: Re: Build Thread:PQD2
Post by: Murdock on October 11, 2015, 04:21:06 PM
Hey, sorry if I missed the info but will there ever be another batch of component kits for the PQD2 Project?
Title: Re: Build Thread:PQD2
Post by: Gustav on October 12, 2015, 05:49:26 AM
Hey, sorry if I missed the info but will there ever be another batch of component kits for the PQD2 Project?

I had help with the tube portion of the kit of the first run, and sourcing, selecting and matching tubes for something like this is no picnic. In fact, its such a large undertaking, I decided against offering anymore when the selection I had help with ran out.

It also took way too much time to match caps to 1% tolerance for stereo compared to what I felt like the max I could charge for a kit was  :)

So youre stuck gathering parts yourself,  building the SS version, or hope someone is a big enough ass to copy my PCB design and offer kits.

Gustav
Title: Re: Build Thread:PQD2
Post by: Murdock on November 26, 2015, 11:17:40 PM
Thanks for the answer!
I decided to gather the parts myself.
And of course I got some questions :D

Are these specs sufficient for the power trafo:

Primary: 2 x 115v (230v)
Secondary:
220V 0,1A
9V 2,5A
5V 0,5A

Just to be sure, because they vary a little from your power transformer.
And concerning the switch resistors: in your PQD2switches-kit.xlsx file you state "10x 200R (High Q), 10x 100R (High Cut) and 10x 1000R (High Boost)". Just to be sure, I really "just" need ten of each (200R, 100R, 1000R) because these are linear switches?
I read your answer to p0ulp post concerning the same question but did'nt quite understand it...
Title: Re: Build Thread:PQD2
Post by: Gustav on November 27, 2015, 02:34:09 AM
Thanks for the answer!
I decided to gather the parts myself.
And of course I got some questions :D

Are these specs sufficient for the power trafo:

Primary: 2 x 115v (230v)
Secondary:
220V 0,1A
9V 2,5A
5V 0,5A

Just to be sure, because they vary a little from your power transformer.
And concerning the switch resistors: in your PQD2switches-kit.xlsx file you state "10x 200R (High Q), 10x 100R (High Cut) and 10x 1000R (High Boost)". Just to be sure, I really "just" need ten of each (200R, 100R, 1000R) because these are linear switches?
I read your answer to p0ulp post concerning the same question but did'nt quite understand it...

Power trafo will probably be fine.

Yes to the question about the switches.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on December 30, 2015, 06:21:51 AM
I'm gathering up components to build one of these myself, but i'm stuck on the inductors, I'd quite like to get something close to the original, but the tap values for the single channel pultec inductors are different for this one - can anyone recommend any?

or do i need to have them custom made? if so, should i get 2 inductors with taps @ 27/47/100mH, and 2 with just 100mH?

or do I actually need individual inductors for each value for this particular design?
Title: Re: Build Thread:PQD2
Post by: Gustav on December 30, 2015, 01:54:24 PM
I'm gathering up components to build one of these myself, but i'm stuck on the inductors, I'd quite like to get something close to the original, but the tap values for the single channel pultec inductors are different for this one - can anyone recommend any?

or do i need to have them custom made? if so, should i get 2 inductors with taps @ 27/47/100mH, and 2 with just 100mH?

or do I actually need individual inductors for each value for this particular design?

You can wire up a multitapped inductor and figure out alternative mounting if you wish, or you can use the Toko inductors I made footprints for.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on December 30, 2015, 04:31:58 PM
i think i will for now, simpler, and a hell of allot cheaper lol might try the sowters in the future tho


I found some sowter in and out transformers that are supposed to work fine for this, not a massive difference in price compared to the LL5402's, not heard either of them before, from what I've read, the LL5402's are "cleaner"? the sowters closer to the original...have only heard the plugin version so i have no idea what that actually means lol
Title: Re: Build Thread:PQD2
Post by: miszt on December 31, 2015, 08:46:08 AM
is there any benefit to having 180V rather than 250V coming from the power transformer, or vice vesa?



lol i was just about to buy a power transformer and they are out of stock oops ..cant seem to find anything similar online, any recommendations? (are there any good build threads about this version, or should i just keep reading up on the single channel version?)
Title: Re: Build Thread:PQD2
Post by: miszt on January 02, 2016, 07:00:51 AM
found a transformer that seems to be the right one (some info on the current capacity in the BOM would be useful, they seem to vary massively, but i got there in the end!)


could still really use a good read up on this tho if anyone has a good link re building it, I'm trying to work my way through ~400 pages of the PeQ thread, but tbh its difficult to pick up the useful info amongst the millions of questions, and I am now even less clear about the build than I was before i started reading lol
Title: Re: Build Thread:PQD2
Post by: Gustav on January 02, 2016, 10:47:06 AM
I'm trying to work my way through ~400 pages of the PeQ thread, but tbh its difficult to pick up the useful info amongst the millions of questions, and I am now even less clear about the build than I was before i started reading lol

Theres a BOM, theres a board with silk screen, theres a sheet of switch values, theres a schematic, and there is a front panel designer file available.

What do you feel is lacking for you  to move forwards with stuffing the boards, ordering or drilling a panel, casing it, and powering this thing up? Id be happy to help fill the gap, if I can.


Gustav
Title: Re: Build Thread:PQD2
Post by: Murdock on January 03, 2016, 07:34:06 AM
Happy  new year to you all!
Hey Gustav, would it be possible to use 24 position rotary switches instead of the 12 position ones? If yes, how would I wire this? There are 24 pins on such a switch but only 12 "holes" on the pcb. Would I need to put resistors between the steps and only take pin 1,3,5,... to the pcb?

Also I read somewhere that, if I were to use shorting switches I would need to use bleed resistor between each step. Is that true for the pqd2? And if yes, how much ohm should the resistors have?
Title: Re: Build Thread:PQD2
Post by: miszt on January 03, 2016, 07:56:18 AM
I'm trying to work my way through ~400 pages of the PeQ thread, but tbh its difficult to pick up the useful info amongst the millions of questions, and I am now even less clear about the build than I was before i started reading lol

Theres a BOM, theres a board with silk screen, theres a sheet of switch values, theres a schematic, and there is a front panel designer file available.

What do you feel is lacking for you  to move forwards with stuffing the boards, ordering or drilling a panel, casing it, and powering this thing up? Id be happy to help fill the gap, if I can.


Gustav

well I've got lots of questions to be honest lol but I feel sure that most have been answered many times already

for eg my previous question about the voltage used for the tubes, is there any benefit to using different voltages? does it affect the dynamic range for eg?

I don't understand the circuit well enough to figure it out myself, i'm coming purely from a recording/mix engineering background, with a vague understanding of the electronics (learnt 20 years ago)


also, apart from physically being 2 pultec filters combined into one PCB, are there any differences between the standard DIY mono pultec that I need to be aware of? or is it exactly the same circuit/components, and I can check voltages in exactly the same way with the same values?
Title: Re: Build Thread:PQD2
Post by: Gustav on January 04, 2016, 03:05:04 AM
I'm trying to work my way through ~400 pages of the PeQ thread, but tbh its difficult to pick up the useful info amongst the millions of questions, and I am now even less clear about the build than I was before i started reading lol

Theres a BOM, theres a board with silk screen, theres a sheet of switch values, theres a schematic, and there is a front panel designer file available.

What do you feel is lacking for you  to move forwards with stuffing the boards, ordering or drilling a panel, casing it, and powering this thing up? Id be happy to help fill the gap, if I can.


Gustav

well I've got lots of questions to be honest lol but I feel sure that most have been answered many times already

for eg my previous question about the voltage used for the tubes, is there any benefit to using different voltages? does it affect the dynamic range for eg?

I don't understand the circuit well enough to figure it out myself, i'm coming purely from a recording/mix engineering background, with a vague understanding of the electronics (learnt 20 years ago)


also, apart from physically being 2 pultec filters combined into one PCB, are there any differences between the standard DIY mono pultec that I need to be aware of? or is it exactly the same circuit/components, and I can check voltages in exactly the same way with the same values?

Its practically identical, aside from the stepped controls, but maybe seeing this is an isolated project instead of comparing it to the single channel would give you one less issue to worry about!? I dont think theres any need to reference the PeQ1 to build it at all.

You can run it at 180V, but I am not smart enough to calculate the loss of headroom (Most likely a lot less than you might think). I usually aim for 220ish, just because...

Gustav
Title: Re: Build Thread:PQD2
Post by: Vac11 on January 04, 2016, 04:37:21 AM
Hi Gustav,

what is the pitch of capacitors legs on the filters (switches) board? I estimate it´s 7.5 mm....  Or more?

What is pitch of two big 4u7F film caps and two big electrolytic 330uF caps on the "main" board?

Thanks

M.
Title: Re: Build Thread:PQD2
Post by: miszt on January 04, 2016, 05:43:04 AM
I'm trying to work my way through ~400 pages of the PeQ thread, but tbh its difficult to pick up the useful info amongst the millions of questions, and I am now even less clear about the build than I was before i started reading lol

Theres a BOM, theres a board with silk screen, theres a sheet of switch values, theres a schematic, and there is a front panel designer file available.

What do you feel is lacking for you  to move forwards with stuffing the boards, ordering or drilling a panel, casing it, and powering this thing up? Id be happy to help fill the gap, if I can.


Gustav

well I've got lots of questions to be honest lol but I feel sure that most have been answered many times already

for eg my previous question about the voltage used for the tubes, is there any benefit to using different voltages? does it affect the dynamic range for eg?

I don't understand the circuit well enough to figure it out myself, i'm coming purely from a recording/mix engineering background, with a vague understanding of the electronics (learnt 20 years ago)


also, apart from physically being 2 pultec filters combined into one PCB, are there any differences between the standard DIY mono pultec that I need to be aware of? or is it exactly the same circuit/components, and I can check voltages in exactly the same way with the same values?

Its practically identical, aside from the stepped controls, but maybe seeing this is an isolated project instead of comparing it to the single channel would give you one less issue to worry about!? I dont think theres any need to reference the PeQ1 to build it at all.

You can run it at 180V, but I am not smart enough to calculate the loss of headroom (Most likely a lot less than you might think). I usually aim for 220ish, just because...

Gustav


thanks, well my only reason for referencing the other project is that this one seems fairly new, so if the circuits are identical, there are probably lots of answers to my questions in the mono version

great thanks, I'm using 220V aswell (the don-audio one which is supposed to be for mono pultec, but using googles Cache function, it seems to have a higher current rating than the one which was on your website - those current ratings would be mighty useful for people i'm sure if you included them in the BOM :) )
Title: Re: Build Thread:PQD2
Post by: Gustav on January 04, 2016, 06:09:57 AM
Hi Gustav,

what is the pitch of capacitors legs on the filters (switches) board? I estimate it´s 7.5 mm....  Or more?

What is pitch of two big 4u7F film caps and two big electrolytic 330uF caps on the "main" board?

Thanks

M.

Capacitors on the filter board are 5mm. Theres a board layout file, and you can use that to check the other two :)

Gustav
Title: Re: Build Thread:PQD2
Post by: Gustav on January 04, 2016, 06:17:25 AM

Hey Gustav, would it be possible to use 24 position rotary switches instead of the 12 position ones?

No, it would be a much bigger job (and mess) than just wiring the filter circuit P2P directly on switches.

Also I read somewhere that, if I were to use shorting switches I would need to use bleed resistor between each step. Is that true for the pqd2?

All you need to do is populate the PCB as is.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 09, 2016, 08:33:34 AM
is there any particular reason that the 220nF polyester caps are listed twice in the BOM? is one of those suppose to be a different value perhaps?


also wondering about the resistors for the switches, how closely do they need to be matched for very good stereo field? I'm looking at ordering 0.1% resistors, because my multi-meter cannot accurately measure 0.1% itself (claims it can, but i don't believe it lol), so there is no point buy 1% and trying to match them myself...but, if 1% difference between them isn't significant, I'd quite like to save myself 5/6's the price...
Title: Re: Build Thread:PQD2
Post by: Gustav on January 09, 2016, 04:51:09 PM
is there any particular reason that the 220nF polyester caps are listed twice in the BOM? is one of those suppose to be a different value perhaps?

Mentioned for the filter and main board separately.

Did you notice the schematic and board layout files are available? You can check issues like that by comparing. Its a good idea to go through it.

also wondering about the resistors for the switches, how closely do they need to be matched for very good stereo field? I'm looking at ordering 0.1% resistors, because my multi-meter cannot accurately measure 0.1% itself (claims it can, but i don't believe it lol), so there is no point buy 1% and trying to match them myself...but, if 1% difference between them isn't significant, I'd quite like to save myself 5/6's the price...

1% is perfectly fine (imo), for stereo matching, matching filter caps will have  much larger impact.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 09, 2016, 11:25:51 PM
is there any particular reason that the 220nF polyester caps are listed twice in the BOM? is one of those suppose to be a different value perhaps?

Mentioned for the filter and main board separately.

Did you notice the schematic and board layout files are available? You can check issues like that by comparing. Its a good idea to go through it.

also wondering about the resistors for the switches, how closely do they need to be matched for very good stereo field? I'm looking at ordering 0.1% resistors, because my multi-meter cannot accurately measure 0.1% itself (claims it can, but i don't believe it lol), so there is no point buy 1% and trying to match them myself...but, if 1% difference between them isn't significant, I'd quite like to save myself 5/6's the price...

1% is perfectly fine (imo), for stereo matching, matching filter caps will have  much larger impact.

Gustav

Yes I went over the board layout, but i couldn't be 100% sure I hadn't missed something, so thought it was worth asking

thanks RE resistors, that's good and bad news, I don't think my multi-meter will give me any useful readings for capacitor matching either tbh, at least not at the % I want - I was reading up on it the other day, and even the "very good" meters can't offer the % match that i think we are talking about here?

I was planning on mostly using this unit in M/S mode anyway, so tbh its not a massive issue, but it would have been nice to have the stereo option aswell; well i'll see what readings i get from my multimeter tomorrow - what % should I be aiming? (obviously as close as possible, but 1%, 5%? or?)


actually i think the real question is, what difference will it make to the frequency band? 5% = +/-1hz or +/-200hz / +-0.1db or +/-6db difference?


this EQ is mainly about color for me, i'll still be doing the core of EQ in my DAW, but if 5% difference means i could have a 3-6db+ difference over a very wide freq range  Left/Right, then that would definitely not be good lol
Title: Re: Build Thread:PQD2
Post by: Gustav on January 10, 2016, 11:06:08 AM
thanks RE resistors, that's good and bad news, I don't think my multi-meter will give me any useful readings for capacitor matching either tbh, at least not at the % I want - I was reading up on it the other day, and even the "very good" meters can't offer the % match that i think we are talking about here?

You can order a bag of each value and sort them to 1%, or just use 5% rated capacitors for the filters (thats all the caps on the front panel board).

I was just trying to put your worries into perspective,  not create new ones.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 10, 2016, 11:38:32 AM
thanks RE resistors, that's good and bad news, I don't think my multi-meter will give me any useful readings for capacitor matching either tbh, at least not at the % I want - I was reading up on it the other day, and even the "very good" meters can't offer the % match that i think we are talking about here?


You can order a bag of each value and sort them to 1%, or just use 5% rated capacitors for the filters (thats all the caps on the front panel board).

I was just trying to put your worries into perspective,  not create new ones.

Gustav

thanks but that doesn't quite answer my question lol or maybe it does and I misunderstood - are you saying that 5% tolerance of capacitors is acceptable for good stereo imaging, or that I should try and match each pair closer to 1%?

tbh I'm not sure my equipment will reliably tell me if a pair of capacitors really are within 1% of one another; I haven't had a chance to check yet - but if 5% tolerance is acceptable for a good stereo image, then that's fine...


(EDIT: going through all my capacitors, I have discovered half of them are infact 10% tolerance, not 5% as I ordered :(  ffs not in the mood to go through returns)
Title: Re: Build Thread:PQD2
Post by: miszt on January 10, 2016, 12:56:34 PM
nope my equipment cant even tell me if they are within 10% of each other, i suspect that the capacitors inside the actual meter are probably higher rated tolerance than the ones i'm trying to test!


a definitive answer on the acceptable tolerance of the capacitors in the filter section would be great :) atm i have a mix of 10% and 5%
Title: Re: Build Thread:PQD2
Post by: Gustav on January 10, 2016, 01:12:18 PM

a definitive answer on the acceptable tolerance of the capacitors in the filter section would be great :)

I am sorry, but the answer I gave in my last post is as "definitive" as I can/will get. You will have to bring your own experience into  making the judgement of how close is close enough. If that experience is non-existent, then building a great sounding EQ and getting it working is an ambitious goal in itself (remember to get someone to vouch for the non-lethality of the build) without getting lost in details and super fine tuning.

"I was just trying to put your worries into perspective,  not create new ones".

My best guess is, if I hadn't made the resistor/cap comparison, you would have populated the boards and never thought of it.

If you want to match caps to 1%, the solution is to buy a bag of each value, buy a meter that can measure capacitance and match the relative values.

Gustav

Title: Re: Build Thread:PQD2
Post by: miszt on January 10, 2016, 01:22:11 PM

a definitive answer on the acceptable tolerance of the capacitors in the filter section would be great :)

I am sorry, but the answer I gave in my last post is as "definitive" as I can get. You will have to bring your own experience into  making the judgement of how close is close enough.

"I was just trying to put your worries into perspective,  not create new ones".

My best bet is, if I hadn't made the resistor/cap comparison, you would have populated the boards and never thought of it.

If you want to match caps to 1%, you have to buy a bag of each value and a meter that can measure capacitance.

Gustav

you aren't answering the question I am actually asking lol which is, what tolerance (for the capacitors in the filters) do you recommend for this project?

as I've said many times, I'm new to this, I have no "experience" to draw on, I have no idea how much of an impact/difference a +/-10% capacitance will have on this circuit, in comparison to +/-1%

(the only reason I have not asked this question before now, is because I have been trying to research the answer for myself, and avoid asking questions which may have already been answered, but I cannot find a definitive answer, but i can assure you it is a question I have been thinking about since discovering the pultec clone and starting to think about building one for myself!)
Title: Re: Build Thread:PQD2
Post by: Gustav on January 10, 2016, 01:35:26 PM

a definitive answer on the acceptable tolerance of the capacitors in the filter section would be great :)

I would recommend you to aim for 5%..

Gustav
Title: Re: Build Thread:PQD2
Post by: dribro on January 12, 2016, 10:16:20 PM
Its been ages to finish these... Only lettering to finish. Sounds very very good. Thanks Gustav.
Title: Re: Build Thread:PQD2
Post by: dribro on January 12, 2016, 10:17:23 PM
Onde more pic
Title: Re: Build Thread:PQD2
Post by: dribro on January 12, 2016, 10:18:15 PM
Onother
Title: Re: Build Thread:PQD2
Post by: dribro on January 12, 2016, 10:19:06 PM
I think thats enough..
Title: Re: Build Thread:PQD2
Post by: Gustav on January 13, 2016, 02:15:56 AM
Its been ages to finish these... Only lettering to finish. Sounds very very good. Thanks Gustav.

Glad you like it  - it wouldn't have existed without Jakob's excellent design. I just moved some things around and did a few measurements to make this.

I see you put resistors in series to make the values on the gain switches, so just for future builder reference.

I did calculations for the switches, but they were off in real-use, so instead, I measured. The table shows the measured values rounded off to real values. It won't make any difference if you have a 220R or a 211R resistor on a  step, as long as they are the same in both sides.  Just try to make them add up to the right total and stay within reasonable limites for rounding to more common values, and you should be fine.

Gustav


Title: Re: Build Thread:PQD2
Post by: dribro on January 13, 2016, 07:53:36 AM
Just my exact thoughts, Gustav.  Its time consuming but resistors in series is a must! Not entirely neat, though. This thing is quiet as a mouse.
And forgot to mention: big thanks to Jakob!
Title: Re: Build Thread:PQD2
Post by: miszt on January 13, 2016, 09:31:07 AM
in use as an EQ, what is the difference between the way the board is laid out, and the way the above was made? just a difference between the gain/atten curves or is there more to it..?

(i'm just going to follow the board, just asking out of interest...)


My PCB's just arrived :) cant wait to get stuck in building this! the pcb's look great (as do all the others I ordered, thanks Gustav!)


Looking at the PCB I'm a bit confused by the tube socket type I need, I bought a pair which where listed as suitable for ECC88/6992's, but they have an extra pin in the middle? I put a little pressure on the pin to see if it moved, but I guess it doesn't come out and I have the wrong socket type?
Title: Re: Build Thread:PQD2
Post by: dribro on January 13, 2016, 04:56:49 PM
I always have a good assortisment of resistors and, when i decided to order the values from the BOM, i figured maybe i should put in the real right values. So series it is! Maybe it won't matter much but as a filter, almost a tiny bit changes things.
Title: Re: Build Thread:PQD2
Post by: miszt on January 16, 2016, 06:25:17 PM
just want to double check, the only electrolytic capacitors which need to be high voltage are the 330uF?

I ask because the 10uF and 470uF electrolytics I have are significantly smaller than the screen print sizes (10uF is 16V and 470uF is 35V, and if i'm following the board correctly, it seems they are not on the 250V path?)
Title: Re: Build Thread:PQD2
Post by: Gustav on January 17, 2016, 02:38:22 AM
just want to double check, the only electrolytic capacitors which need to be high voltage are the 330uF?

I ask because the 10uF and 470uF electrolytics I have are significantly smaller than the screen print sizes (10uF is 16V and 470uF is 35V, and if i'm following the board correctly, it seems they are not on the 250V path?)

The large supply caps (at least one of them) should be higher than the rectified voltage of your HV rail, so that depends on the trafo youre using. (If its 250V, that will be roughly 350V).

The 4700 and 10uF caps are in the heater supply path, so needs to be higher than the rectified voltage of your heater supply 16 6 and 35V are fine.

I would advise you to have someone experienced with you to keep you safe when you're ready to power up this unit.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 17, 2016, 04:54:05 AM
just want to double check, the only electrolytic capacitors which need to be high voltage are the 330uF?

I ask because the 10uF and 470uF electrolytics I have are significantly smaller than the screen print sizes (10uF is 16V and 470uF is 35V, and if i'm following the board correctly, it seems they are not on the 250V path?)

The large supply caps (at least one of them) should be higher than the rectified voltage of your HV rail, so that depends on the trafo youre using. (If its 250V, that will be roughly 350V).

The 4700 and 10uF caps are in the heater supply path, so needs to be higher than the rectified voltage of your heater supply 16 6 and 35V are fine.

I would advise you to have someone experienced with you to keep you safe when you're ready to power up this unit.

Gustav

thanks for the info!

I'll be fine powering this up, although I do not have a clue what is going on in the filter circuit, I've been building mains voltage appliances of all kinds for decades (only had 1 electric shock off the mains, 22 years ago, i don't plan on another haha)
Title: Re: Build Thread:PQD2
Post by: miszt on January 17, 2016, 06:59:56 AM
read up and answered my own question, never mind :) 400V's it is
Title: Re: Build Thread:PQD2
Post by: miszt on January 19, 2016, 10:04:49 AM
I'm nearly ready to think about powering up, but I'm confused about the drop resistor for the 250V, I've got the suggested resistors from the BOM, but haven't put one in yet, what voltage am I supposed to be aiming for after the drop resistor?

(I'm using a 220V (secondary) transformer)

Argh also thought I had 0.5A on the 220V, but it is 0.05A :-/ is that enough for this?
Title: Re: Build Thread:PQD2
Post by: Gustav on January 19, 2016, 11:11:10 AM
I'm nearly ready to think about powering up, but I'm confused about the drop resistor for the 250V, I've got the suggested resistors from the BOM, but haven't put one in yet, what voltage am I supposed to be aiming for after the drop resistor?

(I'm using a 220V (secondary) transformer)

Argh also thought I had 0.5A on the 220V, but it is 0.05A :-/ is that enough for this?

50mA is more than enough.

Aim for the 250V written on the silk screen after the drop resistor...(somewhat lower won't hurt. Dont go higher)

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 19, 2016, 12:07:46 PM
I'm nearly ready to think about powering up, but I'm confused about the drop resistor for the 250V, I've got the suggested resistors from the BOM, but haven't put one in yet, what voltage am I supposed to be aiming for after the drop resistor?

(I'm using a 220V (secondary) transformer)

Argh also thought I had 0.5A on the 220V, but it is 0.05A :-/ is that enough for this?

50mA is more than enough.

Aim for the 250V written on the silk screen after the drop resistor...(somewhat lower won't hurt. Dont go higher)

Gustav

that's a relief thanks! took me ages just to find that transformer lol

still a bit confused, but i might have my calculations wrong...

230V AC to DC ~300V
then to 250V @ 0.025A (guess on the current?)

...gives me ~2K drop resistor?

which is why I'm confused by the 12-20K suggestion in the BOM
Title: Re: Build Thread:PQD2
Post by: Gustav on January 19, 2016, 01:29:35 PM
i might have my calculations wrong...

Could be...In order to check, you could simply try, then measure the voltage drop using a value in the suggested range before replacing with your calculated value if needed...

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 20, 2016, 07:09:59 AM
i might have my calculations wrong...

Could be...In order to check, you could simply try, then measure the voltage drop using a value in the suggested range before replacing with your calculated value if needed...

Gustav

I guess that's what I'll have to do, just don't like pulling those big resistors out, they seem to suck up allot of heat and I find i'm heating the pads far longer than i'd like; i'll see what voltage I actually get after the caps and see

Need to double check some of these caps that are hard to read on the board, have I got this right...

3.3nF (into A2)
15nF (into above cap)
2.2nF (into A3)
10nF (into above cap)
6.8nF (into A5)
3.3nF (into A6)


lastly, a couple of my inductors seem to be matched only within 10%, 4 of them about 2%, is there a recommended tolerance for them? i don't mind getting more and matching them, but i'm not sure how accurate the meter is for inductors, or how close they need to be anyway...
Title: Re: Build Thread:PQD2
Post by: Gustav on January 20, 2016, 12:51:29 PM
have I got this right...

3.3nF (into A2)
15nF (into above cap)
2.2nF (into A3)
10nF (into above cap)
6.8nF (into A5)
3.3nF (into A6)

https://pcbgrinder.com/download/PQD2/PQD2-schem.pdf

i'm not sure how accurate the meter is

Me neither...

or how close they need to be anyway...

Me neither...

If you are matching caps to 10%, it would make sense to do the same for the inductors. If you matched your caps to 5%, if would make sense to do the same for the inductors, and if you matched your caps to 1%, it would make sense to do the same for the inductors.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 20, 2016, 01:12:55 PM
cant read the labels in the schematic either, for the caps going into A1-A3 (apart from the first 3.3nF)




Title: Re: Build Thread:PQD2
Post by: Gustav on January 21, 2016, 03:51:37 AM
cant read the labels in the schematic either, for the caps going into A1-A3 (apart from the first 3.3nF)

3.3, 15, 2,2, 10.

They are in pairs of parallel, so they add up to about 18 and 12.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 21, 2016, 06:15:47 AM
great thanks!

i managed to find a reference to the current draw for g-pultec, 0.005A to 0.006A, which explains the 15K drop resistor (much prefer to work these things out, rather than experimenting lol)


also got a pair of <1% matched inductors from don-audio, so apart form the big 4.7uF cap after the audio transformers, everything is nicely matched :) ...except the tubes...

at the moment I have a pair of "vintage" tubes (siemens), matched fairly closely (110/104 and 108/102 - whatever that means?), but I'd like to get a pair of new-build tubes that are more closely matched, any recommendations? the only recommendations I've found so far are for vintage tubes, with mostly scathing reviews of new ones  :o but i'm sure Manley aren't using NOS in their kit...
Title: Re: Build Thread:PQD2
Post by: CiaoPatsy on January 24, 2016, 06:33:48 AM
Hey Gustav, just placed an order for this.

I'm looking at the switch resistor value sheet. Is the column in blue the typical resistor values that can be dropped in and used?  Sorry if this has been asked. I'm not completely clear on this part of the build.
Title: Re: Build Thread:PQD2
Post by: miszt on January 24, 2016, 07:14:34 AM
all the resistors marked blue in the spreadsheet are standard values, you can get them all on RS online - I did find that RS had a huge mark up on a few of the values, for eg the 1K resistors were something like £1.50 each lol you can get them on ebay for ~99p for 30-50; but most on RS where ~0.15p (still a bit over priced, but even tho they are standard values, many of them cant be found on ebay)
Title: Re: Build Thread:PQD2
Post by: Gustav on January 24, 2016, 07:32:38 AM
Hey Gustav, just placed an order for this.

I'm looking at the switch resistor value sheet. Is the column in blue the typical resistor values that can be dropped in and used?  Sorry if this has been asked. I'm not completely clear on this part of the build.

Check the schematic - the resistors are introduced in series for each step, adding them up one by one. So, its just series resistance.

The blue column represents the value at each step rounded to E96. The only reason its E96 is because I searched Google for a rounding formula, couldn't find one for E24, and making it was a bit over my head.

Theres no real need to use the odd values within a few %, as long as they are identical on both channels, and as long as your total resistance on the switch adds up to the same total.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 25, 2016, 08:03:49 AM
doh managed to forget to flip from AC to DC on meter.  :-[ :P
Title: Re: Build Thread:PQD2
Post by: Gustav on January 25, 2016, 08:43:50 AM
Some how I am getting 700V after the drop resistor (15k)  :/ nothing smoked or exploded thank ****, not going to hold my breath over the tubes tho, I am confused as hell now, that means I need more like a 90K drop resistor, but, I feel like something must be wrong surely?

Was expecting something around 220V-230V...


1. What are the specs on your transformer?

If HV secondary is around 240, 700V suggest you may have wired 2x110V primaries (or a single 220/230 primary)  for 220/230V and powered it on a 110V outlet.

2. If your tubes are not running, the resistor won't do anything, since no current is being drawn, but before considering that further, make sure to wire the trafo correctly.

3. I know I am repeating myself, but wiring a trafo correctly is something best learned on low power projects. When you make a mistake like that and not be able to realise it after the fact, it suggests you are not going to be able to guarantee the safety of your own work, and in this case, that could be fatal.

So please, get someone local with the necessary experience to help you.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 25, 2016, 08:54:41 AM
(as edited above, I was reading with ac switched on meter lol all fine now, just need 20k resistor instead)
Title: Re: Build Thread:PQD2
Post by: miszt on January 25, 2016, 10:03:37 AM
as I have said before, I have plenty of experience with mains voltage appliances, the transformer is not wired up incorrectly, there is no danger of me electrocuting myself or burning the house down! just a danger of me looking a bit silly because I forgot to flip from HV-DC to HV-AC on my meter :P


anyway...does the power/io board require the filter board to be attached in order to properly "experiment" with the drop resistor? because I am not actually getting much of a drop, its ~347V before the resistor, and 320~330V after (I've tried 15K and 20K), so I'm guessing that without a load from the filter board, i'm wasting my time until the filter board is attached?

still got a few parts on order for the filter board (the 3 pin Connector plugs/sockets arnt all the same size on the board, doh!), wondering if I can simulate it with a resistor across the connections for the filter board?
Title: Re: Build Thread:PQD2
Post by: Gustav on January 25, 2016, 10:39:32 AM
I'm guessing that without a load from the filter board, i'm wasting my time until the filter board is attached?

No, the filter is passive, so it will not load your plate supply.

The tubes in the active make-up gain stage (both) need to be inserted and heater supply needs to be running - usually easy to verify by the glow, but its best to have a second meter giving you a heater voltage read-out.

LM317 can shut off due to thermal excess if its not properly cooled. We are drawing a lot of current, so its not uncommon in this project. This would cause you to lose the regulated heater supply.

IF that checks out, check voltage before and after the drop resistor, check the drop, calculate current draw, calculate needed drop resistor - or experiment with a larger value/resistors add up in series if you dont have them in larger values.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 25, 2016, 12:37:23 PM
hmm well, I was getting only 0.5V at the +/- of the diode bridge coming from the 9V AC, so I switched it out wondering if it might be faulty, but now I'm only getting 0.1V; wrong type of diode bridge perhaps? I thought the only difference between when was the amount of current they could handle...

0.0V @ 6.5V pad, unsurprisingly if nothing is making it thru the bridge
Title: Re: Build Thread:PQD2
Post by: Gustav on January 25, 2016, 01:13:14 PM
hmm well, I was getting only 0.5V at the +/- of the diode bridge coming from the 9V AC, so I switched it out wondering if it might be faulty, but now I'm only getting 0.1V; wrong type of diode bridge perhaps? I thought the only difference between when was the amount of current they could handle...

0.0V @ 6.5V pad, unsurprisingly if nothing is making it thru the bridge

Set your meter to read DC after the bridge (the bridge "turns AC into DC"), and for reference, check the VAC on the heater input before the bridge.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 25, 2016, 01:19:06 PM
hmm well, I was getting only 0.5V at the +/- of the diode bridge coming from the 9V AC, so I switched it out wondering if it might be faulty, but now I'm only getting 0.1V; wrong type of diode bridge perhaps? I thought the only difference between when was the amount of current they could handle...

0.0V @ 6.5V pad, unsurprisingly if nothing is making it thru the bridge

Set your meter to read DC after the bridge (the bridge "turns AC into DC"), and for reference, check the VAC on the heater input before the bridge.

Gustav

did that already, 0.1V DC at the +/- pins of the diode bridge, the AC going in is 10V

just reading up on the LM317, and finding conflicting information, I ordered an LM317T, but I have been sent a LM317MT, which seems to be limited to 500mA out, rather than 1.5A+ on the LM317 and LM317T - could that be it? although I cant see why it would limited the voltage on the output of the diode bridge...
Title: Re: Build Thread:PQD2
Post by: Gustav on January 25, 2016, 01:49:09 PM


did that already, 0.1V DC at the +/- pins of the diode bridge, the AC going in is 10V

just reading up on the LM317, and finding conflicting information, I ordered an LM317T, but I have been sent a LM317MT, which seems to be limited to 500mA out, rather than 1.5A+ on the LM317 and LM317T - could that be it? although I cant see why it would limited the voltage on the output of the diode bridge...

Remove regulator, check solder work, check orientation of bridge, check AC on input pins of bridge if it checks out, check DC on output pins of bridge, then replace removed regulator with suitable regulator.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 25, 2016, 02:23:11 PM


did that already, 0.1V DC at the +/- pins of the diode bridge, the AC going in is 10V

just reading up on the LM317, and finding conflicting information, I ordered an LM317T, but I have been sent a LM317MT, which seems to be limited to 500mA out, rather than 1.5A+ on the LM317 and LM317T - could that be it? although I cant see why it would limited the voltage on the output of the diode bridge...

Remove regulator, check solder work, check orientation of bridge, check AC on input pins of bridge if it checks out, check DC on output pins of bridge, then replace removed regulator with suitable regulator.

Gustav


done all that, managed to find an LM317T, put that in instead ... now the fuse has blown lol its a slow blow 500mA, but having read up on the difference between the T and MT, it seems I should be using a fuse >1.5A?

edit: triple checked everything and put a 3A fuse in, all working nicely, voltage a little low now (179V), but easily sorted :)
Title: Re: Build Thread:PQD2
Post by: miszt on January 26, 2016, 09:14:46 AM
what type of 3pin connector is used to connect the filter and gain boards? I've tried 4 different types so far, none of them fit lol; I don't want to solder the wires on at the moment, as I'm sure i'll end up faffing about with one of the boards once I finally "finish"
Title: Re: Build Thread:PQD2
Post by: Gustav on January 26, 2016, 11:01:43 AM
what type of 3pin connector is used to connect the filter and gain boards? I've tried 4 different types so far, none of them fit lol; I don't want to solder the wires on at the moment, as I'm sure i'll end up faffing about with one of the boards once I finally "finish"

I never used a connector there - just dropped the random connector footprint on the PCB for a spaced 3 way and wired it.

You should measure the pin spacing if you want to find a suitable connector.

You sure weren't kidding when you said you had a lot of question...

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 26, 2016, 12:31:44 PM
what type of 3pin connector is used to connect the filter and gain boards? I've tried 4 different types so far, none of them fit lol; I don't want to solder the wires on at the moment, as I'm sure i'll end up faffing about with one of the boards once I finally "finish"

I never used a connector there - just dropped the random connector footprint on the PCB for a spaced 3 way and wired it.

You should measure the pin spacing if you want to find a suitable connector.

You sure weren't kidding when you said you had a lot of question...

Gustav

I measured them already, 3mm, unfortunetly putting "3mm pitch header" into search doesn't bring me much joy :/ ...so there must be a name for this particular type of socket, if you can remember/check the original file, that would be awesome :) (the tube sockets I have are extremely stiff, and i know that when it comes to replacing the tubes, i wont be able to do it safely without removing the board, so I'm putting headers on all the connection points)


:P I have way more questions than I have posted up, I've only posted the ones I couldn't find an answer to and figured others might find the answers useful


ps. apart from the headers and 1 missing capacitor, i'm finished! will post pics soon, apart from lots of questions and the tedium of matching components, this was surprisingly easy to build! cant wait to switch it on after years of using the UAD2 versions :) ...long as it works haha but I've been careful to triple check everything before soldering

thanks for being patient lol enjoyed building it tho, cant wait to get stuck into the other boards!
Title: Re: Build Thread:PQD2
Post by: miszt on January 27, 2016, 06:43:02 AM
...also, what type of caps should I have for the 1uF and 2.2uF on the filter baord? I've bought several sets now, different voltages, but all of them huge, the wires wont even fit in the hole, even if I could fit them at a strange angle..
Title: Re: Build Thread:PQD2
Post by: Gustav on January 27, 2016, 08:06:19 AM
...also, what type of caps should I have for the 1uF and 2.2uF on the filter baord? I've bought several sets now, different voltages, but all of them huge, the wires wont even fit in the hole, even if I could fit them at a strange angle..


1. Please gather up your remaining, basic questions about gathering parts and completing the assembly of the unit in a single post.

2. Please do this with the goal of building this unit as its laid out, rather than expanding your issues by trying to build a finely tuned, modded version of it.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 27, 2016, 10:41:01 AM
I have not "modded" the unit at all, I am keeping the components within 1% tolerance because I am a professional engineer and I want to use this unit in my work, if I want to put in the extra work to do that, well that's up to me, whats the problem?

I have only 2 questions:

1. what is the connector type, where you placed a "random" connector

2. what specific type of 1uF and 2.2uF fit the pads on the filter board?


i'm not going to apologize for being a noob with questions; don't really understand why you are being difficult about it; it would have been quicker just to answer the questions than post that impatient and unhelpful post (not for the first time either).
Title: Re: Build Thread:PQD2
Post by: Majestic12 on January 27, 2016, 12:24:54 PM
Every 2,2uF and 1 uF capacitor with 5mm lead space will fit the pcb.
It is very easy to find something suitable with nearly all electronic distributors.
WIMA brand capacitors have a wide range of different sizes and values.
For example:

http://de.farnell.com/kemet/rsbcc4220z310k/folienkondensator-pet-2-2uf-50v/dp/2496060?MER=i-9b10-00002068


Gustav maybe is a bit fed up because you are new to DIY things and want to make so much "perfect" right from the start without having enough basic knowledge about parts, electronics etc yet..
Many questions about your desired part toleraces and so on aren't so easy to answer.
One thing about DIY is that you also gather this knowledge with every project you make. But you have to accept that you can't make a masterpiece as an apprentice. And even a master makes mistakes and doesn't know everything

I could simply open a new can of worms by telling you that the magnetic coupling between the inductors on your filter pcb will probably change the total inductance and filter response far more than your 1% tolerance parts, which is probably something you did not take into account yet and probably didn't know at all.

Neither did I until I made a LC filter board on my own a few weeks ago....and I have some years of experience now.

Title: Re: Build Thread:PQD2
Post by: miszt on January 27, 2016, 12:43:40 PM
Every 2,2uF and 1 uF capacitor with 5mm lead space will fit the pcb.
It is very easy to find something suitable with nearly all electronic distributors.
WIMA brand capacitors have a wide range of different sizes and values.
For example:

http://de.farnell.com/kemet/rsbcc4220z310k/folienkondensator-pet-2-2uf-50v/dp/2496060?MER=i-9b10-00002068


Gustav maybe is a bit fed up because you are new to DIY things and want to make so much "perfect" right from the start without having enough basic knowledge about parts, electronics etc yet..
Many questions about your desired part toleraces and so on aren't so easy to answer.
One thing about DIY is that you also gather this knowledge with every project you make. But you have to accept that you can't make a masterpiece as an apprentice. And even a master makes mistakes and doesn't know everything

I could simply open a new can of worms by telling you that the magnetic coupling between the inductors on your filter pcb will probably change the total inductance and filter response far more than your 1% tolerance parts, which is probably something you did not take into account yet and probably didn't know at all.

Neither did I until I made a LC filter board on my own a few weeks ago....and I have some years of experience now.

no one learns without asking questions, that is what forums are all about, it would be better not to reply at all, than be unhelpful, impatient and deliberately difficult

I did actually already come across a discussion about the inductors, and I'm now using a pair of don-audio, matched @ 1%, and each will be in a little metal enclosure, the way they are on the original pultec


sure I cant expect perfection first time around, but I do not see the point in doing anything without at least having a goal in mind
Title: Re: Build Thread:PQD2
Post by: Majestic12 on January 27, 2016, 12:49:19 PM
Miszt, I'm sure that Gustav had no intention to be unhelpful or rude to you. He's a very fine guy.  And he as already helped you a lot

Your capacitor size question is something very easy to answer and I'm sure you would have found out on your own by looking a bit around.

Just go on with your built and try to get it up and running. I'm sure it will work and sound fine and you'll surely want to make more things in the future which also will get better and better.
Title: Re: Build Thread:PQD2
Post by: Gustav on January 27, 2016, 01:10:45 PM
i'm not going to apologize for being a noob with questions; don't really understand why you are being difficult about it

Theres nothing wrong with being a "n00b" or asking "n00b" questions. What you are doing now is using a trouble shooting thread (and a separately created thread on modding and tubes) as a train-of-thought live chat to bridge the gap between your ability and your ambition.

Your ambition is to be to build a finely tuned, modded version of this without even knowing how resistors and capacitors affect the filter, or how to find  5mm pitch 2u2F cap.

Theres nothing wrong with taking on a project without knowing those things. Lots of people who have successfully built a unit have no clue - They just dont widen the gap between their ability and ambition more than necessary, which means they can focus on managing the BOM without making a separate post for each BOM item.

In order for me to help you further, I simply ask you to patiently gather up your questions into a forum-friendly post, rather than use this as a chatroom, and adjust your ambition to something realistic - getting a working unit running.

Saying I am being unhelpful seems incredibly rude to me. I have spent 4 forum pages trying to help you, one part at a time, and rather than spend another 4, 8 or 12 more pages, I am making a simple request, which could also help you regain some focus.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 27, 2016, 01:34:41 PM
Perhaps I overstated my noob level, I know how a capacitor filters a signal, but that doesn't mean I can tell you exactly how every bit of this circuit is working or how much of a difference it makes using 100nF rather than 101nF - which is why I have asked (and didn't get a reply)

Gustav I appreciate your help, but you have infact refused to answer my questions a few times, until I've repeated them 3-4 times; the last 2 questions are the latest example (note that you still haven't answered lol you are just whinging because I'm not using the format you prefer - I'm sorry but the way I work is to do things in stages and make sure its right before moving on, I cannot store up lots of different problems and then come back to them; this is a trait of ADHD which I have to deal with every day)

My questions are troubleshooting, for eg couldn't read labels on pcb/schematic, couldn't find a suitable connector for the "random" one used on the pcb, couldn't work out the drop resistor value because i coupdnt find a definitive current consumption figure (you could have told me when I posted up my calculations)

Perhaps it is a language issue and I am misinterpreting things, but if I ask the same question 3-4 times and dont get an answer...well, what else am I supposed to think? So far I have been assuming that it wasn't intentional and tried to be equally patient
Title: Re: Build Thread:PQD2
Post by: Gustav on January 28, 2016, 03:24:48 AM
What I am trying to say is, its obvious you need to have a goal, but that goal has to be realistic as in "get a working EQ going".

I am asking you to adjust that ambition to better suit your ability, and I am asking you to adjust your method, so theres not a separate post from you for every part mentioned in the BOM mixed with ambitions of fine tuning and modding the unit.

For example.

I know how a capacitor filters a signal

If this is true, then it makes no sense to ask how much a cap value will change the amplitude and frequency of a setting.

if 5% difference means i could have a 3-6db+ difference over a very wide freq range  Left/Right, then that would definitely not be good lol

First of all, switching the cap changes the frequency, and if you know how a filter works, its very simply to take the 2,2uF value for 20Hz, then deduce the impedance from that. When you have that, you can check how far the frequency strays with a change in capacitance.

..so my answer

You can order a bag of each value and sort them to 1%, or just use 5% rated capacitors

...is a combination of "If you have to ask", "Dont worry about it" and "It will be fine", and it seems like you won't accept that. It should be obvious from my answer I find 5% to be sufficient, so wether you need to match the more closely is a value judgement.

I sometimes find the need to match them to 1%, but thats based on my own experience, and my own value judgement. I also go back and tweak needed values after shooting some curves if I am building something like that, since the goal ultimately refers to the match of the equalisation curves, not the capacitor or inductor values.

I ask the same question 3-4 times and dont get an answer..

Some of the answers you get are, "wire it up, and dont worry about the connector", and "Try a resistor in the range suggested in the BOM", but those answers do not seem to be acceptable to you, so you ask again and pile on more questions.

If the working solution suggested is not good enough,  it means you will have to work it out for yourself rather than ask 3 more times. 

note that you still haven't answered lol you are just whinging because I'm not using the format you prefer

So rude....

I suggested a way forward that would help me be able to help you better, and I gave clear reasons for making that suggestion. I do feel a sense of duty with regards to helping people move forward with the projects, so I did this rather than stop replying to you.

It seems like your answer can be boiled down to "stop whinging, and just answer my question". I can only see that as a complete devaluation of my time and effort.

----

Search Mouser for "wima 5mm", click "capacitors" on the list that appears, check "5mm" in the lead spacing box, check 2.2uF in the capacitance box. Voltage rating is not an issue for the filter caps.

Hope you figure out the rest.

Gustav
Title: Re: Build Thread:PQD2
Post by: miszt on January 28, 2016, 09:49:25 AM
..I am asking you to adjust your method,

I cant expect everyone to understand the complexities of ADHD, but asking me to adjust my method is like asking a blind person to try opening their eyes wider.

if you don't have time to check the original PCB file and see what connector you used, then just say so...really no need to drag it out into all this unpleasantness; sorry if you feel I am being rude, but I don't expect someone to spend so much time avoiding answering a simple question
Title: Re: Build Thread:PQD2
Post by: dribro on February 04, 2016, 08:27:43 AM
3 pin connector? that's easy. I used the cheapest ones possible.

http://www.ebay.com/itm/20PCS-3-Pin-Screw-Terminal-Block-Connector-5-0mm-Pitch-301-3P-301-3P-3pin-/291497781534?hash=item43de9f291e:g:4NsAAOSw3xJVXLZE

you'll have to bend the legs a little
Title: Re: Build Thread:PQD2
Post by: CiaoPatsy on March 07, 2016, 03:04:59 AM
Hey Gustav, just getting mine up and going - running into an issue.

I have NOS ecc83 tubes in. They power up fine when unit is turned on but slowly start to become dimmer until they seem to completely turn off.  Doesn't matter what value drop resistor I use (from the ones you recomend in the BOM) they still ultimately loose their glow.  Once they start dimming the voltage at the drop resistor slowly goes up and up to 350ish. When they are both on before they start dimming I get a reading of 220dc.

I have the Don Audio transformer for the 2 channels of G Pultecs, that I read could be used for this project.

When I put just one of either tube in, it stays on fine. I've tried it with each tube and they are both lighting up and staying on when just one tube is inserted. Either socket works the same with either tube. They stay on and drop resistor voltage is consistent.

I'm getting 6v on the 6.3v measure point.

Also, when I powered on the first time I had a short and the fuse blew. I found it was shorting  to ground along the positive side of 4700uf cap to the input on the regulator and to a pin on the rectifier. Probed around and found a bad solder. Could I have damaged something and maybe enough current isnt being supplied?

This is my first build with any tubes in it, so thank you for bearing with me!

Looking forward to get this running.
Title: Re: Build Thread:PQD2
Post by: Gustav on March 07, 2016, 03:54:01 AM
Hey Gustav, just getting mine up and going - running into an issue.

I have NOS ecc83 tubes in. They power up fine when unit is turned on but slowly start to become dimmer until they seem to completely turn off.  Doesn't matter what value drop resistor I use (from the ones you recomend in the BOM) they still ultimately loose their glow.  Once they start dimming the voltage at the drop resistor slowly goes up and up to 350ish. When they are both on before they start dimming I get a reading of 220dc.

I have the Don Audio transformer for the 2 channels of G Pultecs, that I read could be used for this project.

When I put just one of either tube in, it stays on fine. I've tried it with each tube and they are both lighting up and staying on when just one tube is inserted. Either socket works the same with either tube. They stay on and drop resistor voltage is consistent.

I'm getting 6v on the 6.3v measure point.

Also, when I powered on the first time I had a short to ground from the positive side of 4700uf cap to input on the regulator and the a pin on the rectifier. Probed around and found a bad solder. Could I have damaged something and maybe enough current isnt being supplied?

This is my first build with any tubes in it, so thank you for bearing with me!

Looking forward to get this running.

Hi Patsy.

You mention you have 6.3V on the heater, but your symptoms are coherent with the heater supply regulator getting too hot after a bit of action and going into protection mode, resulting in loss of heater supply. When only one tubes is in, you are drawing less current through the regulator and generating less heat.

If the heater supply is lost, the tubes stop drawing current, and the high voltage will no longer be influenced by any drop resistor value. (ohms law states that V = I x R, if your heater supply is lost, I = 0, so V = 0 no matter which value you put for R).

Alternatively, you may not have sufficient current available on your heater supply.

If your regulator is shutting down, fix with heat sink (Its common to use a pad and mount the regulator to the case for heat dispersion on this project if are regulating from 12V).

If you have insufficient current, use different trafo.

And just to mention it (I assume replacing a part is the result of thorough research, but just to make sure its been mentioned). You are sure that you can replace the ECC88 for ECC83? From my limited knowledge about tubes, I would say no, even though the pinout should make it "work", but not "really work". I also dont know if there are discrepancies in heater, current draw.

Gustav
Title: Re: Build Thread:PQD2
Post by: bernbrue on March 07, 2016, 03:55:45 AM
You need ECC88 for this, not ECC83. They are not compatible.
Bernd
Title: Re: Build Thread:PQD2
Post by: CiaoPatsy on March 07, 2016, 04:49:37 AM
Hey Gustav, thanks for the fast response. Youre the man!

I'm sure you are right. I just have the regulator free standing right now. I wasn't thinking about how much current the tubes need...like I said first tube project....doooh.  I shoulda noticed since all the pictures I've seen on completed units had it heatsinked. I'll get that heatsinked today and give it another shot.

I have ECC88's. Typo on my part. Thanks for looking out for me.

Last question...I'm wiring up the xlrs now and I'm looking at the schematic.....am I right that pins 1 + 3 go to the transformer and pin 2 goes to ground?

 
Title: Re: Build Thread:PQD2
Post by: miszt on March 07, 2016, 07:29:43 AM
I used a small 3cm heatsink with 1cm wings and a silver thermal/conductive paste, does the job nicely


(I wired all the XLR pins to the PCB, and the input XLR's ground pins additionally connected to the mains ground/chassis ground; signal is as clean as it gets)


Title: Re: Build Thread:PQD2
Post by: CiaoPatsy on March 08, 2016, 04:41:59 AM
It was totally the heat sink. I got a big one strapped on there now and it's firing up fine. Thanks for all the help everyone.

I used a small 3cm heatsink with 1cm wings and a silver thermal/conductive paste, does the job nicely

(I wired all the XLR pins to the PCB, and the input XLR's ground pins additionally connected to the mains ground/chassis ground; signal is as clean as it gets)

I will wire it up just like this when I'm done testing!

Sounds really, really nice. Thanks for the great project!
Title: Re: Build Thread:PQD2
Post by: stereo78 on March 17, 2016, 04:16:29 PM
Dear Gustav,

i've built your Version of the Pultec, thanks for Layout of a Stereo Version. Everything seems to be Okay, it sounds good, distortion about 0,2%, very little Noise ... a hot voltage regulator, but with a bigger heat sink it seems okay.

I'm not satisfied with two things: there is a overall Level drop of 3 dB (Bypass/Hi-Z input), [email protected], and 1,5dB more with the Bypass-Switch off (=Filter in). (And I discovered a 2,5 dB Peak at 24 Hz, measurement above, but it vanishes with a 600 Ohm Load... that might be normal?)

Is there a way to calibrate the Bypass / EQ in Gain leakage, and perhaps the overall Gain?

Thanks ^^

(http://)
Title: Re: Build Thread:PQD2
Post by: Gustav on March 18, 2016, 12:42:31 AM


Is there a way to calibrate the Bypass / EQ in Gain leakage, and perhaps the overall Gain?


Check the discussion thread for Jakob's PeQ design. Asked and answered tons of times.

Gustav
Title: Re: Build Thread:PQD2
Post by: Hobbyist on April 11, 2016, 09:41:59 AM
Interested in this project.
Learning and collected already some of the components :)
Always wanted a Tube EQ in my studio. Will take my time on this one..

Good job Gustav !

Title: Re: Build Thread:PQD2
Post by: Murdock on April 25, 2016, 06:38:09 PM
Hey, I got a question regarding the grounding and XLR wiring... I'm a bit confused because of the different layout.
Am I right that I have to connect the XLR pin 1 to PCB pad 2?
So
XLR 1 -> PCB 2
XLR 2 -> PCB 1
XLR 3 -> PCB 3

And should I connect the Input XLR ground pins (1) together and to chassis ground?
And should I wire anything to the ground pad on the PCB or why is it there?
Title: Re: Build Thread:PQD2
Post by: Murdock on May 03, 2016, 11:23:51 PM
Nevermind, figured it out...
Testing the unit now, will post results later.
Title: Re: Build Thread:PQD2
Post by: Hobbyist on May 04, 2016, 03:45:56 AM
Nevermind, figured it out...
Testing the unit now, will post results later.

Good luck !
Gonna start building mine next week, looking forward to see your version.
which ECC88 did you used?

Best


Title: Re: Build Thread:PQD2
Post by: Murdock on May 04, 2016, 02:10:25 PM
Thanks Hobbyist! I got PCC88 Phillips Miniwatt tubes from Bowie. Can't recommend him enough! Very nice guy and very nice tubes!
Got it up and running! Voltages seem to  be ok.  No smoke  8)
215V after the drop resistor
6.1V at the heater
Lamp is glowing, tubes also.
Should I change the 18k drop resistor to a 15k resistor to get near to the 250V and 6.3V?
But I have another problem... The high frequency boost on my first channel does nothing except at 2.1 Khz. This one works...
I thought it would be a capacitor I accidentally touched with the solder iron and it has a melted spot. But the capacitor is in the attenuetor section and this seems to work fine...
Does anyone have a clue where I should expect the error to be?


Title: Re: Build Thread:PQD2
Post by: Gustav on May 05, 2016, 04:04:32 PM

215V after the drop resistor
6.1V at the heater

I would make sure the regulator is actually regulating and not just passing DC, since thats a tiny, tad low

Measure the voltage on the input pin of the LM317 to see if its about the same as its spitting out.

No need to change the drop resistor imo.


]The high frequency boost on my first channel does nothing except at 2.1 Khz. This one works...
I thought it would be a capacitor I accidentally touched with the solder iron and it has a melted spot. But the capacitor is in the attenuetor section and this seems to work fine...
Does anyone have a clue where I should expect the error to be?

Are you sure its 2.1kHz? I think  you have an error in switch programming - the little programming pin, stuck on the wrong side of the switch in position 6. So when you are in 1, you are really in 6, and in 2, you go to 7, which is not a meaningful position.

Even so, and just for the sport of it, it shouldn't  be too hard to trace.

Take a look at the schematic

The HF switch is a 2 pole/6 position switch. (Sort of like 2 switches with 6 positions, moved by one control)

Now, trace what I write in the schematic.

On the first position (2.1kHz), the signal passes through a cap to A1 (two in parallel, but lets call it one to simplify), goes from one pole of the switch to the other (A to C), goes up to C1, and then through all the inductors in series (C2, C3, C4, C5 and C6 are dead) and moves on.

On the second position, the signal passes through the same cap, down to A2, A always goes to C, regardless of the position you're in, and now C goes up through C2, which does not go through the first cap, but still passes through the rest of them in series.

(If you switch is programmed correctly, and the working frequency is in fact 2.1kHz).

Looking for trouble ont he first pole.

Capacitor switched in on A1 and A2 is the same, so its not the capacitor, or the signal  to the capacitor coming to the input (they work on A1!)

 It could be the connection from the capacitor to A2.  So basically, see if A2 is connected properly

Looking for trouble on the second pole

The inductors are in series, and on C1, they are all switched in, so you already know the signal makes its way through all of them.

In the second position (C2), you simply bypass one of them, so you could look for trouble on C2 on the switch.

...but

You say all the frequencies over 2k1Hz are dead, and now that you know how to trace the signal though the schematic, you'll see that a missing signal on the A3/C3 would have to be a bum connection around the cap going to A3, or a bad connection from C3. 

Its logically possible that you could have a whole gang of bad connections (fourth, fifth and sixth would be separate to, as you can see), but before testing a hypothesis that involves error stacking, check the simpler one - programming pin error.

And if you thought you didn't know how to read a schematic, I hope I managed to prove you wrong.

Gustav

Title: Re: Build Thread:PQD2
Post by: Murdock on May 06, 2016, 07:13:04 AM
Hey Gustav, thanks alot for your explanation and help, much appreciated!
I measured the voltages on the LM317.
I got 12.83V on the input
           6.1V on the output
           4.86V on the adjust pin

What exactly do you mean by programming pin? Do you mean the little stopping washer? Or is there a pin inside the switch which I also can adjust?
If you mean the stopping washer, than I got that right.

Edit:
resoldered A2 and C2 to no avail, even completely wired a new switch because I thought the old one was maybe faulty.
Still got the same behavior...
Now I will resolder every capacitor in the high section. I hope there is no faulty one...
Title: Re: Build Thread:PQD2
Post by: Gustav on May 06, 2016, 02:11:37 PM

If you mean the stopping washer, than I got that right.


Just to make 100% sure your switch is not caught on the wrong side of the pin.

Remove the pin, turn the switch fully counter clockwise, then add the pin to position 6 again.

Re:your idea to resolver every capacitor, reread my info/trace the schematic. I tried to make it clear that you could be sure that if the first step (capacitors included) worked, this would not be the reason for fault on step two.

Gustav
Title: Re: Build Thread:PQD2
Post by: Murdock on May 06, 2016, 02:34:10 PM
Yes, I did exactly that. Also, if the switch was programmed the wrong way, and step 1 was in fact 6, than it should have a boost at 18khz right? And that is definatelly not the case. I ran some music through the working channel, boosting at 2.1khz and compared it to the faulty channel, and it sounded the same. So I think it is really boosting at 2.1khz...
So if the capacitors can't be the fault, what can it be? It has to be the switch? No other possibilty?
Title: Re: Build Thread:PQD2
Post by: Gustav on May 06, 2016, 03:02:54 PM
Yes, I did exactly that. Also, if the switch was programmed the wrong way, and step 1 was in fact 6, than it should have a boost at 18khz right? And that is definatelly not the case. I ran some music through the working channel, boosting at 2.1khz and compared it to the faulty channel, and it sounded the same. So I think it is really boosting at 2.1khz...
So if the capacitors can't be the fault, what can it be?

Broken through plating or similar - i can be anywhere on the identified path. I dont have time to check right now, but I dont see what else it could be off the top of my head.

Try this -  Take a few pieces of wire, and see if you make the connections were investigating directly from the components to the switch pins.

And this - compare the channels with your meter to look for discrepancies on the connections were investigating.

Gustav

Title: Re: Build Thread:PQD2
Post by: Murdock on May 06, 2016, 04:02:00 PM
Yep, seems to be the plating or traces... At A, A1, A2, C and C1 I get the same resistance. At all other I get nothing...
At the working channel I get the same resistance in all steps.
Looks like the signal stops at C2 right?
So I just connected C2  to the 100mH pad with a wire, and still nothing...
(Just to make things clear; the signal goes through, but is not affected by the high frequencies except 2.1khz).

EDIT: Got it!!
It was the inductor...
I have the custom inductors from Don Audio with the adapter PCB and there is no real indicator on how to place the inductor... And guess what, I've put it in the wrong way. Really  weird because I've put it in the same way like the other inductor in the working channel. I should write Aaron, maybe he can make a marking on his inductors...

Anyway, I'm really relieved now... Thanks alot Gustav for your time and help!
I will post pictures and some notes tomorrow.
Title: Re: Build Thread:PQD2
Post by: Gustav on May 07, 2016, 12:33:16 AM
EDIT: Got it!!
It was the inductor...

Awesome - really glad your unit is working :)

Gustav
Title: Re: Build Thread:PQD2
Post by: Murdock on May 07, 2016, 11:56:26 AM
It lives!!  :o

(http://s32.postimg.org/44vaq5cud/IMG_9617.jpg)

(http://s32.postimg.org/5ryaglt1h/IMG_9610.jpg)

(http://s32.postimg.org/tmrheyypx/IMG_9603.jpg)

I know, I know, it probably is a troubleshooting nightmare and noisier than the default layout, but I'm done and it sounds just amazing! And it is in fact really really quite (except a little buzz on the right channel from the lamp cable, but only noticable when I really crank up the volume to the maximum. I have to shield it somehow).
But I would not build it like that again I think...  :P I think function over looks should be my motto when I start the next project.

So big thanks to you Gustav for this amazing project! Thanks to Aaron from Don Audio for the inductors. Frank from frontpanels. de for making the panel for me. And Bowie for the tubes!
You guys rock!

Title: Re: Build Thread:PQD2
Post by: Gustav on May 07, 2016, 12:58:58 PM
it is in fact really really quite (except a little buzz on the right channel from the lamp cable, but only noticable when I really crank up the volume to the maximum. I have to shield it somehow).


Are you sure its the lamp cable? Inductor on the right is a bit close to your toroid - could be worth checking if thats the culprit.

Other than that, excellent looking build! And re:trouble shooting - the inductor you are using does make a difference for the trace I posted to help - always highlight info on "mods" in bold to make helping easier :)

Gustav
Title: Re: Build Thread:PQD2
Post by: Murdock on May 07, 2016, 04:11:08 PM
Yeah, the buzz varies when I move the cable around. It also gets alot quiter when I touch the lamp holder... is that an indicator that it isn't making proper contact with the chassis/ground?

And yes, sorry! I should've told you that I'm using different inductors. But your tip on measuring for discrepancies between the two channels got me on the right track. And I also learnt a few different things on the way. So thanks alot Gustav!

EDIT: yep, grounded the lamp holder to the star ground and that minimized buzz by quite a bit. The little buzz that is left is probably because of the inductor being to close to the PT, like you said. But I only can hear it when I turn the level to max... So I'm happy how it is now!
Can't thank you enough!
Title: Re: Build Thread:PQD2
Post by: Murdock on May 08, 2016, 06:23:41 PM
Hey Gustav, I got a question concerning grounding... again  ;D
I read your post on general grounding in the G-Pultec thread:

"General grounding:

- Power input gnd to chassis gnd.
- Wire XLR's pin1's together.
- Wire from xlrF(input)pin1 to input gnd on PCB.
- Also wire from this point xlrF(input)pin1 to chassis gnd."

I did it like this and like in your "Wire Guide" pdf, where only on the first channel input pin 1 is connected to gnd on pcb. And each additional channel pcb gnd is not connected.
But could it be that it would be better to also connect input pin 1 from the second channel to the gnd on pcb?
Or would that create a so called ground loop?
Because I'm starting to think that the buzz I hear is a grounding issue. The left channel (which has a connection between XLR and pcb gnd) is dead silent. But the right channel isn't.

And I noticed that the inductor in my AML ezMEQ-5 is also quite close to the power transformer and I get no buzz there...
Would be nice if you could elaborate a bit on this matter. This whole grounding thema is really confusing, especially because everybody seems to handle it different...
Title: Re: Build Thread:PQD2
Post by: Gustav on May 09, 2016, 02:58:53 AM
could it be that it would be better to also connect input pin 1 from the second channel to the gnd on pcb?
Or would that create a so called ground loop?
Because I'm starting to think that the buzz I hear is a grounding issue. The left channel (which has a connection between XLR and pcb gnd) is dead silent. But the right channel isn't.

The ground is connected between the XLRs on the PCB, so you would just create loops with your method.

I also think its a bad place to start your investigation based on your previous comment.

Yeah, the buzz varies when I move the cable around. It also gets alot quiter when I touch the lamp holder... is that an indicator that it isn't making proper contact with the chassis/ground?

1. Disconnect the lamp  - see what happens. If it solves your issue, try drawing the ground from the lamp back to a different point (you may be using the GND test points now. Also, is this an LED or an actual lamp?)
2. Try rotating the toroid - see what happens..

And I noticed that the inductor in my AML ezMEQ-5 is also quite close to the power transformer and I get no buzz there...

Could be one is shielded, and the other is not, or any number of other factors (the power trafo plays a role as well) . I mentioned it as something worth investigating, and to do that, you can rotate the toroid a bit, try shielding it, try unmounting the inductor and move it around a bit to see if it influences the sound.

I do not have experience with the inductor you are using in the build, or the inductor you are referring to, so these are just suggestions for variables that are easy to investigate.



This whole grounding thema is really confusing, especially because everybody seems to handle it different...

The method I put up for the project should work, but your build is unique, with a unique layout, a unique choice of inductors etc.

So, other than the suggestions I made so far - experiment!

Gustav
Title: Re: Build Thread:PQD2
Post by: Murdock on June 06, 2016, 07:52:41 AM
Hey Gustav,
thanks for your answer. Will experiment next time I opened the unit up!

I have another question:
In the "Transformer lists for projects" thread, it is stated that one could use the Peerless S-217-D as an output transformer in the G-Pultec.
Is that true? Could I use the S-217-D in the PQD2? If yes, would I have to make any adjustments to the circuit because of the higher impedance?
(http://www.bunkerofdoom.com/xfm/PEERLESS1953/Peerless_1953_08_0001.jpg)
Title: Re: Build Thread:PQD2
Post by: Hobbyist on July 06, 2016, 02:57:50 PM
Hey guys,

I'm sharing my finished version. Have to say, after comparing with the software editions from UAD and WAVES, the sound is brilliant! So useful for many processes ! Very nice project to work on and learned a lot from it. It took a while to get 1% tolerance with all the components, but i'm glad I did it to get decent stereo balance.

Good stuff Gustav !

Cheers
M



Title: Re: Build Thread:PQD2
Post by: Hobbyist on July 06, 2016, 02:58:50 PM
.. and another one.
Title: Re: Build Thread:PQD2
Post by: Vac11 on November 12, 2016, 11:27:27 AM
Hi Gustav,

i have some troubles with my PQD2.  Yesterday I turn on the EQ for the first time (with asistence of my friend - el. tech, he checked all wiring before).

After 30 second the bridge rectifer behind the 9VAC connector was very hot.  After another 30 sec was the round bridge rectifer dead. Where could be a problem?

I used B380C1500 (W10M, 1000V/1,5A.) for both bridge rectifers...
Toroid trafo spec. is:
TS 30VA
PRI: 2x115V
SEC:
> 230V (35mA)
> 9V (2A)
> 6V (0,5A)

Today I changed both bridge rectifers and also LM317 and same problem... Where can we start?

Thanks

M.
Title: Re: Build Thread:PQD2
Post by: bernbrue on November 12, 2016, 01:08:17 PM
Disconnect the power transformer and measure the AC voltages of the secondary.  I don't know what kind of torroid transformer you've got there, but the white leads do not look like they were secondary windings.
Bernd
Title: Re: Build Thread:PQD2
Post by: Vac11 on November 12, 2016, 01:35:52 PM
Thank you, we try it.

It is custom toroid from toroidy.pl. On the toroid is "sec white 9V, sec purple 230V, sec black 6V"... 6V is for lamp and relays bypass pcbs, relays clics corectly and lamp shines.
Title: Re: Build Thread:PQD2
Post by: bernbrue on November 12, 2016, 01:59:21 PM
Ok, I would measure if anyway.  Check the colour code once again. Do the bridge rectifiers have the correct orientation?  ~ ~ +- . What did you do with the 4,7 caps? 
Bernd
Title: Re: Build Thread:PQD2
Post by: Vac11 on November 12, 2016, 02:03:33 PM
Orientation is 100% correct. There are two big 5u8F soviet PIO cap instead of 4u7F foil caps...

M.
Title: Re: Build Thread:PQD2
Post by: bernbrue on November 12, 2016, 02:11:01 PM
I've never seen a bridge rectifier melting down, so there must be either a short, a cap with wrong polarity or wiring mistake.
Bernd
Title: Re: Build Thread:PQD2
Post by: Vac11 on November 21, 2016, 02:45:20 AM
I think voltage on secondaries are OK:

sec 9V...................9,91VAC (measured)
sec 230V..............239,68VAC

We disconnected input and output xlrs and filter board  from "main" board. We connected toroid transformer secondaries (9V and 230V) to main board and main board worked properly - lamps shone, voltage on the 6,3 VDC point was 6.07 and on the 250VDC point was 179VDC (there is 22K as drop resistor, so I think when I change this resistor for smaler value voltage would be OK in range 210-250VDC). Voltage before this resistor was cca 300VDC.

My problem is somewhere in bypass PCBs wiring. When we conected "shields" (pin 1) from XLRs to main board wago conectors, the bridge rectifer started burn and smell in a few seconds.... When we disconnected shields from mainboard this problem go away....

My wiring diagram attached...

V.
Title: Re: Build Thread:PQD2
Post by: Gustav on November 21, 2016, 06:28:31 AM
I think voltage on secondaries are OK:

sec 9V...................9,91VAC (measured)
sec 230V..............239,68VAC

We disconnected input and output xlrs and filter board  from "main" board. We connected toroid transformer secondaries (9V and 230V) to main board and main board worked properly - lamps shone, voltage on the 6,3 VDC point was 6.07 and on the 250VDC point was 179VDC (there is 22K as drop resistor, so I think when I change this resistor for smaler value voltage would be OK in range 210-250VDC). Voltage before this resistor was cca 300VDC.

My problem is somewhere in bypass PCBs wiring. When we conected "shields" (pin 1) from XLRs to main board wago conectors, the bridge rectifer started burn and smell in a few seconds.... When we disconnected shields from mainboard this problem go away....

My wiring diagram attached...

V.

Seems obvious you have an incongruent 0V reference with your wiring, but I can't see where you are drawing those by your drawn example, or by the pictures - where are you drawing your 9V, and ground reference on the bypass board?

Try looking at the PSU part of the PQD2 schem, that may give you an "aha!?" moment.

 And do you have a schem of the bypass board?

Gustav
Title: Re: Build Thread:PQD2
Post by: Vac11 on November 21, 2016, 07:08:21 AM
Thanks Gustav.

Here is bypass PCB schematic and manual:
http://diy-tubes.com/image/data/manuals/bypass-en-v1.0.pdf

Toroid 6VAC secondaries wires lead to small "rectifer pcb" with four diodes and one electrolytic capacitor. After rectification I have cca +- 8-9VDC.   9VDC wire leads to SPST "bypass" toggle switch and then to bypass pcb "+V" point (on the filter pcb are joined pin holes for DPDT toggle, so filter board is permanent in circuit). From bypass pcb "OV" point leads wire to "-" point on small rectifer board I selfetched. I think maybe here could be my mistake...

Thanks again

V.

EDIT: For clarification I modified my previous wiring schematic....
Title: Re: Build Thread:PQD2
Post by: Vac11 on November 22, 2016, 12:07:23 PM
Small update:

Today I connected right  chanell xlrs direct to main board and sent signal to EQ from DAW.  EQ pass audio without any artifacts. I was very very happy what I heard. Really nice sounding EQ.

I looked at the EQ schematic as Gustav recommended. Is my mistake, that I didnt connect "OV" from bypass pcb to chassis?
Title: Re: Build Thread:PQD2
Post by: Gustav on November 22, 2016, 01:23:45 PM
Small update:

Today I connected right  chanell xlrs direct to main board and sent signal to EQ from DAW.  EQ pass audio without any artifacts. I was very very happy what I heard. Really nice sounding EQ.

I looked at the EQ schematic as Gustav recommended. Is my mistake, that I didnt connect "OV" from bypass pcb to chassis?

I had a hard time following your description, but obviously some ground terminal error like discussed.

Glad it works!

Gustav
Title: Re: Build Thread:PQD2
Post by: Vac11 on November 28, 2016, 02:09:41 AM
Yesterday I tried EQ again. I did some wiring changes. I connected "-" from my small rectifer board to mains pcb ground,  I also connected "OV" from bypass pcb to mains pcb ground.

(http://img16.rajce.idnes.cz/d1603/12/12190/12190416_912a24f9ad17cfbf0b8d549e79b8d7a2/images/wiring1.jpg?ver=0)

Bypass pcbs works corectly. EQ pass uneffected audio in bypass mod. Both chanells. So I think this wiring change was a step in the right direction.

Still have problem with bridge rectifer heating when shields from xlrs are connected. When  connected shields to main pcb WAGO connectors bridge rectifer is very hot in few seconds...

My second trouble is that left channel dont pass audio in "EQ IN" mod. Unfortunately right chanel is OK and sounds amazing so I can compare component after component. I have to try filter section alone with some audio.

So my troubleshoting continues....
Title: Re: Build Thread:PQD2
Post by: Lieto on July 13, 2017, 08:27:47 AM
Hello, I have the same problem as Vac11 ... I use no Bypassboard ... the problem must be elsewhere. 9V bridge is very warm and there is no signal coming out of my unit. I have all the components checked, transformer connected properly etc ... Help pls! The strange thing is, the unit has been running once. Then I decided to mount the LM317 to the housing. Then it overheated the bridge. Have also taken away the LM317 from the housing again, but it does not work.

Greetings Andy

Title: Re: Build Thread:PQD2
Post by: Gustav on July 13, 2017, 01:59:30 PM


So my troubleshoting continues....

I can see you already found a solution earlier, which wasn't really a solution after all, it seems.

I still cant follow what you are doing, and I am sorry, but you have to make it easier to help you, unless you prefer going at it by yourself.

Step 1. Basic configuration to eliminate variables! Take the bypass board out of the equation, return wiring to stock set-up.

Gustav

Title: Re: Build Thread:PQD2
Post by: Gustav on July 13, 2017, 02:04:18 PM
Hello, I have the same problem as Vac11 ... I use no Bypassboard ... the problem must be elsewhere. 9V bridge is very warm and there is no signal coming out of my unit. I have all the components checked, transformer connected properly etc ... Help pls! The strange thing is, the unit has been running once. Then I decided to mount the LM317 to the housing. Then it overheated the bridge. Have also taken away the LM317 from the housing again, but it does not work.

Greetings Andy

Not sure how this is related to VAC 11, but I will try.

1. Bridge may not be specced to pass sufficient current
2. LM317 will not overheat the bridge by being properly cooled, Error is not the operation of connecting it to chassis to cool, error must lie in the manner it was connected, o in something else putting too much load on the bridge.
3. Any dead tubes at this point?

Hope that gives you something to go by.

Gustav

Title: Re: Build Thread:PQD2
Post by: Vac11 on July 13, 2017, 03:27:53 PM
I still have no time for troubleshoting...but im thinking my problem is in grounding. When i conect xlrs PIN 1 to PCB, bridge rectifer get very hot in few seconds.

M.
Title: Re: Build Thread:PQD2
Post by: Lieto on July 13, 2017, 06:07:38 PM
Hi Gustav,

thanks for you're fast reply. I used the W04G-E4/51 Diode with 1.5A at first and the unit runs more or less fine (except of a gain loss around 10dB). Then I mess around with the LM317 and the diode bridge gets toasted...  :-[ I replaced the W04G with a 2W06G Diode (2A 600V). Maybe you're right, the transformer can provide 2.5A on the 9V. But the ECC88 needs only 300mA.

Which diodes do you use Gustav?

My tubes are fine so far, the heater works, got round about 6.1 V  8)

Thanks for you're help! Regards Andy
Title: Re: Build Thread:PQD2
Post by: Gustav on July 14, 2017, 12:52:10 AM
I still have no time for troubleshoting...

When you do, try reverting the unit back to stock as suggested, then take it from there :)

When the stock set-up is verified as working, we can dive into the set-up of the add-on you are working with, but for now, its just a distracting variable.

Hope that makes sense!?

Gustav
Title: Re: Build Thread:PQD2
Post by: Gustav on July 14, 2017, 12:57:31 AM
Hi Gustav,

thanks for you're fast reply. I used the W04G-E4/51 Diode with 1.5A at first and the unit runs more or less fine (except of a gain loss around 10dB). Then I mess around with the LM317 and the diode bridge gets toasted...  :-[ I replaced the W04G with a 2W06G Diode (2A 600V). Maybe you're right, the transformer can provide 2.5A on the 9V. But the ECC88 needs only 300mA.

Which diodes do you use Gustav?

My tubes are fine so far, the heater works, got round about 6.1 V  8)

Thanks for you're help! Regards Andy

No particular diodes. Just wanted to verify that you were using a diode with the capacity to handle the current flow as a start.

6.1V on the heater checks out. .

Since you report the unit to be working before heat sinking the LM317, I'd guess you ran into trouble there, but now you are reporting a 10dB loss before doing so, so its possible, theres another problem with the build.

Did you isolate the LM317 from the case when you mounted it to the case for heat sinking?

Whats your high voltage reading? Before and after the drop resistor.

- also be aware, you can check the filter separately. Signal to input pin on the filter, check signal on output.. there will be a drop, but you can check it none the less, and isolate any problems to the gainstage 100% by doing so.

Gustav
Title: Re: Build Thread:PQD2
Post by: Lieto on July 14, 2017, 01:42:26 PM
No particular diodes. Just wanted to verify that you were using a diode with the capacity to handle the current flow as a start.

6.1V on the heater checks out. .

Since you report the unit to be working before heat sinking the LM317, I'd guess you ran into trouble there, but now you are reporting a 10dB loss before doing so, so its possible, theres another problem with the build.

Did you isolate the LM317 from the case when you mounted it to the case for heat sinking?

Whats your high voltage reading? Before and after the drop resistor.

- also be aware, you can check the filter separately. Signal to input pin on the filter, check signal on output.. there will be a drop, but you can check it none the less, and isolate any problems to the gainstage 100% by doing so.

Gustav

Hi Gustav,

no I didn't isolate the LM317, maybe this was the Problem. Also I got some errors with the grounding ... Today I visit a friend and he helps me out. We replace the 1uf elko after the  LM317 with a ceramic cap. And add a film cap between the LM317 and GND, he sad its to prevent the LM317 from oscillating, also this will keep the temperature low. The diode bridge still gets hot (around 50 degrees). My friend says its to small to handle the current (2A). When its toasted I will replace it with a bigger one. Now the unit is almost done. I got a little gain drop between bypass and eq on (2.5dB). But this is a common problem and I can fix it.  8) 8) 8)

Thank you very much for you're Support!!!! ;)

Here are some pics, maybe it can help other people to fix some problems.

Greetings Andy

(http://up.picr.de/29786160vq.jpg)

(http://up.picr.de/29786161fr.jpg)
Title: Re: Build Thread:PQD2
Post by: Gustav on July 14, 2017, 03:36:52 PM

no I didn't isolate the LM317, maybe this was the Problem.

Yes, definitely a problem.

Not sure about the mods you are doing  shouldn't be necessary to build the unit with no kinks at all.

Gustav
Title: Re: Build Thread:PQD2
Post by: Lieto on July 15, 2017, 07:53:27 AM
Yes, definitely a problem.

Not sure about the mods you are doing  shouldn't be necessary to build the unit with no kinks at all.

Gustav

I am sure it will run without the additional stuff, but he is an very good electronic engineer and i trust him. The unit sounds great and the noise floor is relativ low, just a little peak at 50Hz at -95dB when I fully boost every band. If I don't make any boost its around -115dB. It also creates some nice harmonic distortion. I compare it with the Waves Pultec Plugin and its very close to each other. I am very Happy!!!  ;D ;D ;D

Maybe I will improve the the amp section some time. My friend says the is a way to get 6dB more gain from the amp. Just replacing some components and change the wiring of the transformers. But for now its very good. Maybe I don't use it for mastering and the mod is not necessary. 

Greetings Andy

Title: Re: Build Thread:PQD2
Post by: relurelu on September 01, 2017, 12:11:10 PM
   Hi, guys, I got my V.1 board. I got it without any BOOM, documentation... The big caps from the valves board is unknown for me, bleeder is a new thing for me... bridge values... Maybe I will find more. Maybe somebody is good to upload or link to your documentation.
Title: Re: Build Thread:PQD2
Post by: Gustav on September 01, 2017, 02:24:33 PM
   Hi, guys, I got my V.1 board. I got it without any BOOM, documentation... The big caps from the valves board is unknown for me, bleeder is a new thing for me... bridge values... Maybe I will find more. Maybe somebody is good to upload or link to your documentation.

Its in the project documentation on the product page.

Gustav
Title: Re: Build Thread:PQD2
Post by: rprimmett on September 05, 2017, 11:57:17 AM
Hey guys, I have two of these to build and am super excited. I'm going to be using Edcor XS1100's and am wondering if I could also get a power transformer from them too. I open to some suggestions for the power transformer but at the least need to know what kind of current the 250V and 9V will be drawing.
Title: Re: Build Thread:PQD2
Post by: leo-666 on October 07, 2017, 10:25:50 AM
Hello, Gustav.

I did not want to post this question to the topic since it's a noob question.
Hoped to get your direct answer.
But seems like your private inbox is full.

Amazing project.
But I'm a bit confused about switch resistor values.
I downloaded PQD2switches-kit.xlsx file.
Where to find needed values ?
PCB layout states about 100 needed ones around the switches as I understand.

And one more question about inductors.
I've chosen a goal to reach 1% tolerance between channels.
And I did not find good 1% matched fixed inductors at Mouser.
So I ordered Don Audio ones.

https://www.don-audio.com/G-Pultec-Inductors-matched-pair-22mH69mH169mH269mH

They're ok ?
At first I was confused with different induction 22mH,69mH,169mH,269mH.
But then understood that it's a different abbreviation.
22 + 47 + 100 + 100.
22 = 69 = 169 = 269.
So seems like everything is ok.


Best regards...
Title: Re: Build Thread:PQD2
Post by: Gustav on October 07, 2017, 02:16:47 PM
Hello, Gustav.

I did not want to post this question to the topic since it's a noob question.
Hoped to get your direct answer.
But seems like your private inbox is full.

Amazing project.
But I'm a bit confused about switch resistor values.
I downloaded PQD2switches-kit.xlsx file.
Where to find needed values ?
PCB layout states about 100 needed ones around the switches as I understand.

And one more question about inductors.
I've chosen a goal to reach 1% tolerance between channels.
And I did not find good 1% matched fixed inductors at Mouser.
So I ordered Don Audio ones.

https://www.don-audio.com/G-Pultec-Inductors-matched-pair-22mH69mH169mH269mH

They're ok ?
At first I was confused with different induction 22mH,69mH,169mH,269mH.
But then understood that it's a different abbreviation.
22 + 47 + 100 + 100.
22 = 69 = 169 = 269.
So seems like everything is ok.


Best regards...

Check the excel file again. Each line shows a resistor ladder for a switch, both sides.

3 of them just indicate to use idenical resistors.

I would use single inductors as indicated in the project description. You can also match those ok with a few of each, if precision is your biggest concern.

I doubt the Don Audio inductors are 1%, probably 10%, but maybe I am wrong.

edit:sorry, I was wrong, I see you linked to a matched pair :)

Gustav
Title: Re: Build Thread:PQD2
Post by: leo-666 on October 07, 2017, 05:32:54 PM
(https://s1.postimg.org/80lwixk08b/Resistors.jpg) (https://postimg.org/image/80lwixk08b/)

For low boost and low cut switches do I need to follow Target R, Step R, Res96, Total Res column ?
Or a graphic lines ? (they are doubling Total Res column)

 For Hi Q - 200R  x10
 Hi Cut  -   100R   x10
 Hi Boost - 1000R  x10

And I need is to double all this for a second channel ?

Title: Re: Build Thread:PQD2
Post by: Gustav on October 09, 2017, 02:16:50 AM
(https://s1.postimg.org/80lwixk08b/Resistors.jpg) (https://postimg.org/image/80lwixk08b/)

For low boost and low cut switches do I need to follow Target R, Step R, Res96, Total Res column ?
Or a graphic lines ? (they are doubling Total Res column)

 For Hi Q - 200R  x10
 Hi Cut  -   100R   x10
 Hi Boost - 1000R  x10

And I need is to double all this for a second channel ?

Hi Leo.

The resistors are in series on the switches, which is why you are seeing individual steps as well as total resistance. Letters and numbers are marked on the boards/schematic.

The log pots are differentiated, the lin pots are just 10 x of the the same (value divided by 10 for for 10 steps/11 positions).

You can change the values as you wish. The chart just shows the values I had in the first build of this myself.

Gustav
Title: Re: Build Thread:PQD2
Post by: leo-666 on October 09, 2017, 01:38:57 PM
Thanks, Gustav.

Still quite don't get it. Sorry.
This is not my first build, but certainly more complicated than the previous ones.
And without simple insctructions I won't be able proceed to Mouser cart.

For example, we take resistor A9 or F9 that belongs as I understand to the right column. (Low cut)
What resistance to choose ? 91000, 21000, 21000, or 91310 ? To say simpler, what column to look in ? (
Same for B4/G4. 862, 278, 280 or 863R ?

And about HiQ, HiCut and HiBoost dividing by ten. Absolutely can't understand this.
I.e. Hi Cut, we have 100R stated.
How it must be divided or multiplied to achieve 10 different values ?


Thousands sorries for my stupidity )
Title: Re: Build Thread:PQD2
Post by: Gustav on October 09, 2017, 05:16:27 PM
Thanks, Gustav.

Still quite don't get it. Sorry.
This is not my first build, but certainly more complicated than the previous ones.
And without simple insctructions I won't be able proceed to Mouser cart.

For example, we take resistor A9 or F9 that belongs as I understand to the right column. (Low cut)
What resistance to choose ? 91000, 21000, 21000, or 91310 ? To say simpler, what column to look in ? (
Same for B4/G4. 862, 278, 280 or 863R ?

And about HiQ, HiCut and HiBoost dividing by ten. Absolutely can't understand this.
I.e. Hi Cut, we have 100R stated.
How it must be divided or multiplied to achieve 10 different values ?


Thousands sorries for my stupidity )

I am sorry, but I'm not sure how I can explain it better than the previous post...

Maybe if you consider that these were pots, and they are converted to stepped switches in this project. Two were log, and three were linear.

...and the resistors are added in series for each step.

Gustav
Title: Re: Build Thread:PQD2
Post by: leo-666 on October 11, 2017, 10:30:37 AM
I watched all the traces on a scheme and now have complete understanding how it works. Thanks.

Question about power traffo.
In a local store there is 240V @ 45mA ; 12V @ 1A toroidal transformer for sale.
I guess 45 mA line is fine, but what about 1A ? Is it enough ?
Tranny rated 20W.
Title: Re: Build Thread:PQD2
Post by: rprimmett on October 12, 2017, 10:51:22 AM
Hey guys, I have two of these to build and am super excited. I'm going to be using Edcor XS1100's and am wondering if I could also get a power transformer from them too. I open to some suggestions for the power transformer but at the least need to know what kind of current the 250V and 9V will be drawing.

Any help  ;D
Title: Re: Build Thread:PQD2
Post by: rprimmett on January 11, 2018, 04:41:24 PM
I have most things sorted out but need on small bit of assistance. I'm using Edcor XS1100's instead of the LL5402's but cant seem to figure out the correct wiring.  Does anyone have a pin for pin wiring conversion.
Title: Re: Build Thread:PQD2
Post by: rprimmett on January 12, 2018, 02:09:08 PM
I think I got it figured out following this diagram, pin 6 of the ll5402 is pin 8 on the xs1100

(http://www.gyraf.dk/gy_pd/pultec/gy_pd_sch.gif)
Title: Re: Build Thread:PQD2
Post by: phelar on May 09, 2018, 04:58:56 PM
Hi!

Someone got the docs for this build?
Title: Re: Build Thread:PQD2
Post by: Gustav on May 10, 2018, 08:13:12 AM
Hi!

Someone got the docs for this build?

https://pcbgrinder.com/index.php?route=product/product&path=59_61&product_id=63

Near the bottom

Gustav
Title: Re: Build Thread:PQD2
Post by: andow on November 23, 2018, 07:24:12 PM
Does anyone else find that the bass cut does too much with the standard resistor values?  ???
Title: Re: Build Thread:PQD2
Post by: Gustav on November 26, 2018, 01:45:58 AM
Does anyone else find that the bass cut does too much with the standard resistor values?  ???

Easily changed, just lower the resistor values.

The high cut and high boost total resistance are critical, the bass cut total resistance is not, so you can solder resistors in parallel or swap as you like.

Gustav
Title: Re: Build Thread:PQD2
Post by: weiss on January 20, 2019, 07:33:52 AM
Hey guys, i'm having bit of a trouble here..

my pqd2 passes audio but only in mono and there is no sound processing in any way. i can hear the noise of the device but the bypass or any other switches won't affect the signal. (note: i had to wire two 2x6 switches (high q and high boost) and change their position compared to the pcb. if there was a disconnection somehow, would it affect the complete eq processing pathway?)

Is there a way to begin trouble shooting?
I'm building the device for a client - bad timing   :-[

I hope someone can bring me closer to the problem.

thanks for any help!
Ansgar
Title: Re: Build Thread:PQD2
Post by: Gustav on January 20, 2019, 08:00:45 AM
Hey guys, i'm having bit of a trouble here..

my pqd2 passes audio but only in mono and there is no sound processing in any way. i can hear the noise of the device but the bypass or any other switches won't affect the signal. (note: i had to wire two 2x6 switches (high q and high boost) and change their position compared to the pcb. if there was a disconnection somehow, would it affect the complete eq processing pathway?)

Is there a way to begin trouble shooting?
I'm building the device for a client - bad timing   :-[

I hope someone can bring me closer to the problem.

thanks for any help!
Ansgar

Hi Weiss..

If there was an error on the wiring of the switches, that would definitely influence the operation of the unit.

You can check the input/output stage by jumping the to/from filter connections.

You can check the filters with a signal, without the gain stage active.

No scope to trace the signal?

Gustav
Title: Re: Build Thread:PQD2
Post by: weiss on January 20, 2019, 08:50:51 AM
Thanks for the response gustav.
Is it correct, that the numbers on the input and output section refer to the corresponding numbers on the xlr pin?
I'm gonna try to follow the signal with my scope.

best regards
Title: Re: Build Thread:PQD2
Post by: Gustav on January 20, 2019, 11:17:24 AM
Is it correct, that the numbers on the input and output section refer to the corresponding numbers on the xlr pin?

No - if you look at the PCB, you should be able to see that all the middle pads are connected to one node - common.

Youll have to do 1 hot on the input and 1 cold on the output, or vice versa to have phase coherence.

Title: Re: Build Thread:PQD2
Post by: weiss on January 21, 2019, 05:16:37 AM
No - if you look at the PCB, you should be able to see that all the middle pads are connected to one node - common.

Youll have to do 1 hot on the input and 1 cold on the output, or vice versa to have phase coherence.

oh thanks, that solved it !! :)
Title: Re: Build Thread:PQD2
Post by: fonzobrown on January 22, 2019, 04:40:45 AM
Hi all, please  someone may share the BOM and possibly the schematic of PQD2 because Gustav ( pcbgrinder) don't provide anymore on website ?

I may need even the VECA ones

i've the pcbs from almost 2 years and now i'd like to assembly my units

Your help will be really welcomed

Thanks

Roberto
Title: Re: Build Thread:PQD2
Post by: Vac11 on January 22, 2019, 05:00:50 AM
After some years im actually done. Thanks!!!
Title: Re: Build Thread:PQD2
Post by: Vac11 on January 22, 2019, 05:04:51 AM
Hi all, please  someone may share the BOM and possibly the schematic of PQD2 because Gustav ( pcbgrinder) don't provide anymore on website ?

I may need even the VECA ones

i've the pcbs from almost 2 years and now i'd like to assembly my units

Your help will be really welcomed

Thanks

Roberto

Hi Roberto,

pleas see attached file and follwed link:
https://drive.google.com/file/d/1j54y3SC_FtMufzDibf-tx6QDIriQKlMm/view?usp=sharing

M.
Title: Re: Build Thread:PQD2
Post by: fonzobrown on January 22, 2019, 06:37:54 AM
Thanks so much Vac11

Now i'm still miss VECA ( Comp ) BOM

https://groupdiy.com/index.php?topic=59576.msg906357#msg906357

Really Thanks for the help
Title: Re: Build Thread:PQD2
Post by: andow on January 24, 2019, 06:51:33 PM
After some years im actually done. Thanks!!!

What are these boxes on the left?  ???
Title: Re: Build Thread:PQD2
Post by: Murdock on January 24, 2019, 08:59:16 PM
What are these boxes on the left?  ???

Quite sure these are the output caps. Old russian PIO capacitor
Title: Re: Build Thread:PQD2
Post by: weiss on January 24, 2019, 11:06:35 PM
...could also be weights, to make the unit seem heavy and valuable  ;D ;D
Title: Re: Build Thread:PQD2
Post by: Vac11 on January 25, 2019, 12:12:04 AM
Quite sure these are the output caps. Old russian PIO capacitor

Exactly... I think 4.7uF...
Title: Re: Build Thread:PQD2
Post by: andow on January 26, 2019, 01:41:38 AM
Ah, now I see them missing on the PCB...
Wow, these are huge!  ;D
Title: Re: Build Thread:PQD2
Post by: Potato Cakes on February 08, 2019, 09:12:24 PM
I've a bit of a head scratcher on one of these I just completed. High and low boost controls do not work, but everything else does. The other odd thing is that when I do a low cut, the low boost brings it back up forming a dip in the signal instead of a shelf like it should. But It won't actually boost the low end. I've pulled it all apart and doing my due diligence with checking solder connections whilst tracing signal and comparing it to the schematic, but so far nothing. Oh, and i have about 10dB of boost from the make up gain amplifier, whether the EQ section is in circuit or not. The lead connections from the filter board are connected to the corresponding silkscreen connections and are making an electrical connection. The board is super easy to build and it's pretty spread out so if there was solder bridge it should be easily visible. The audio is clean in and out, but when I turn the bass boost up there is a slight buzz that comes in.

One thing I did notice is that the two header connections on the main PCB are not making identical connections to the transformers. I thought I had found an error when two of the header pins had 13 ohms between them and the same ones on the other header did not, but I saw that the pins with the 13ohms were connected to the transformer. I was testing the wrong pins and also found that there is only one pin connects ground to the filter board as that is all is needed, so the middle pin for channel 2 is not connected because there is no need for two ground connections. The traces for the other pins are identical.

I'll get back to it later this evening and poke around some more. It seems that something is bypassing the high and possibly low boost switches and that same possible thing is causing the 10dB increase of gain, like it's not seeing the loss that you would expect with a passive filter section. If someone has some ideas in the meantime I'd gladly like to hear them.

Thanks!

Paul


See next post
Title: Re: Build Thread:PQD2
Post by: Potato Cakes on February 09, 2019, 12:54:46 AM
Got back to it tonight and did some listening with pink noise. I can hear the high frequency sweeping with a narrow bandwidth setting and I can see that the amount of boost increases with increase of frequency, but still not to the level of what it should be. The lows are still the same. I did notice that I can only boost the lows to the unity level from where they are cut. When I start to decrease the amount of cut, I can see and hear the frequency notch returning to unity level, but the amount of boost does not change past that. So the controls are doing something, but the other Pultec style EQs that I have built and used there is a significant amount of change when boosting. The HF and LF attenuation seem to work fine as does the bandwidth control. I can measure resistance changes between the switch positions and there seems to be continuity amongst the components to match the schematic. According to the results I'm getting from each test, this should be working. When I crank the lows to 10 it should rattle my teeth instead of what it is doing at the moment.

For the 10dB of gain, is this normal? I checked my resistor at the input and output transformers and I do indeed have a 10k between the secondaries of the input and 2k2 on the output. I double checked to make sure there wasn't a boosted gain stage in my rig by plugging the I/O XLRs together and I get unity gain coming back into the interface.

This is a pretty easy build with minimal interconnects and generously spaced components, so I'm a bit confused why this is not a happy EQ. If the problem was no sound or no change at all I could find it fairly easily, but the behavior that is currently being exhibited is a bit baffling.


I am a disgrace to the DIY community. I had build these boards a while back then they sat until I finally got a case made. Somehow when I initially stuffed these boards I confused the resistor arrays to their respective switches. The good news is I now have a reason to break in my new desoldering pump.

I can't believe how amazing I am...

 Thanks!

Paul
Title: Re: Build Thread:PQD2
Post by: Potato Cakes on February 09, 2019, 06:19:43 PM
Got it done. The 10dB gain boost is gone and everything works. Oh, and it sounds amazing. I'd be curious if different tubes would make any meaningful difference with this circuit. Has some one did any sort of testing in regards to tube selection? It already is quiet and smooth sounding. The question is for science.

Thanks!

Paul
Title: Re: Build Thread:PQD2
Post by: Potato Cakes on February 09, 2019, 06:20:14 PM
One more. For the kids.
Title: Re: Build Thread:PQD2
Post by: Gustav on February 20, 2019, 01:29:08 PM
One more. For the kids.

Nicely done!

Gustav
Title: Re: Build Thread:PQD2
Post by: erquere on May 02, 2019, 01:09:54 PM
Hi ! Looking for the pcbs of the PQD2, would anyone have spare ?

Title: Re: Build Thread:PQD2
Post by: Potato Cakes on May 02, 2019, 01:28:02 PM
https://www.pcbgrinder.com/produktside/pq2