EQP-1S5 500 series PULTEC ---- HELP/BUILD thread

[weiss]

- Bandwith pot cuts the low end and makes signal more quiet when turned completely CCW


thanks
weiss

Hi, have you been able to get anywhere with that?  It would help if you could run a frequency sweep and post the resulting graph(s) to see exactly what is going on.  Take a look at the following site, it has a list of various passive filters, and graphs of the response to expect, you might be able to figure out what is wrong with yours by comparing your frequency response graph to the ones on the page.  BTW, the link will take you to the low shelf cut section (scroll up and down to see more stuff), but take a look to see if you don't have a solder bridge to ground in the BW pot or at the inductor leads. 

good luck!

i checked now, no incorrect solder bridges. I will exchange the opamp and try to get a clean signal through the device as soon as i am at home! thanks for the help 

weiss

 

[porkyman]

update: my unit only does this when unit is switched off. both when powered on but bypassed, but also when i turn the power off on the lunchbox.  when engaged i was able to calibrate. but i noticed if i barely boost the signal spikes hard and distorts.

 

[mitsos]

having problem with my unit. just plunging it into lunchbox causes a crazy distortion noise. the lunchbox isnt even plugged in. theres no signal running through it, but its making my ad converter scream.

The unit is designed so that it goes into bypass when power is off, can you verify if this happens with yours? With the unit off (or in bypass) you should have connectivity between the XLRs, (pin 2 to pin 2, and pin 3 to pin 3).  Also, can you check if you have connectivity between one of the inputs and ground while in bypass or off?

tried other unit in the same slot and it was fine. tried switching out ops and no change. you cant see it in the pic but d1 and d2 are installed correctly, and c_dc is jumpered. i saw that revision 2 boards needed to be wired for ground. those posts were in 2013 so i figured the issue has been resolved.

There was an issue with the edge connector on the first batch of Rev 2 EQs, but the unit in the picture you posted seems to have the corrected PCB.  To be safe, look for connectivity between the a ground point on the PCB (you can use any pcb pad connected to the top layer ground plane) and the ground pins on the edge connector. 

update: my unit only does this when unit is switched off. both when powered on but bypassed, but also when i turn the power off on the lunchbox.  when engaged i was able to calibrate. but i noticed if i barely boost the signal spikes hard and distorts.

Does this happen with both EQs? If one works correctly then you may find it easiest to look for differences between the two units.  Check DCR between various points and ground and hopefully you'll find it.

 

[mitsos]

- Bandwith pot cuts the low end and makes signal more quiet when turned completely CCW


thanks
weiss

Hi, have you been able to get anywhere with that?  It would help if you could run a frequency sweep and post the resulting graph(s) to see exactly what is going on.  Take a look at the following site, it has a list of various passive filters, and graphs of the response to expect, you might be able to figure out what is wrong with yours by comparing your frequency response graph to the ones on the page.  BTW, the link will take you to the low shelf cut section (scroll up and down to see more stuff), but take a look to see if you don't have a solder bridge to ground in the BW pot or at the inductor leads. 

good luck!

i checked now, no incorrect solder bridges. I will exchange the opamp and try to get a clean signal through the device as soon as i am at home! thanks for the help 

weiss

Hi, did you check this visually or also with a DMM?  Let us know if the opamp makes a difference. Also, try to get a graph of the freq response,  so we can see exactly what is happening. 

 

[porkyman]

having problem with my unit. just plunging it into lunchbox causes a crazy distortion noise. the lunchbox isnt even plugged in. theres no signal running through it, but its making my ad converter scream.

The unit is designed so that it goes into bypass when power is off, can you verify if this happens with yours? With the unit off (or in bypass) you should have connectivity between the XLRs, (pin 2 to pin 2, and pin 3 to pin 3).  Also, can you check if you have connectivity between one of the inputs and ground while in bypass or off?



thanks fro responding mistos. there is connectivity between xlr's, but not between input and ground, if i did this right i tested pin 2 on input in back of lunchbox, to pin 2 on the output of lunchbox. both 2 and 3 pins had connectivity. for the ground test i tested pin 1 to  2/3 of the input xlr on back of lunchbox. there was no connectivity.

tried other unit in the same slot and it was fine. tried switching out ops and no change. you cant see it in the pic but d1 and d2 are installed correctly, and c_dc is jumpered. i saw that revision 2 boards needed to be wired for ground. those posts were in 2013 so i figured the issue has been resolved.

There was an issue with the edge connector on the first batch of Rev 2 EQs, but the unit in the picture you posted seems to have the corrected PCB.  To be safe, look for connectivity between the a ground point on the PCB (you can use any pcb pad connected to the top layer ground plane) and the ground pins on the edge connector. 

i went ahead and wired it like i saw earlier in the thread just to be sure. there was no change.

update: my unit only does this when unit is switched off. both when powered on but bypassed, but also when i turn the power off on the lunchbox.  when engaged i was able to calibrate. but i noticed if i barely boost the signal spikes hard and distorts.

Does this happen with both EQs? If one works correctly then you may find it easiest to look for differences between the two units.  Check DCR between various points and ground and hopefully you'll find it.

i dont have two units. (yet). when i said i tried "other unit," in the slot  i meant a different unit. it was a preamp.

someone else earlier said this was the easiest build hes ever done, so of course there was a problem... could not agree more.  its such a simple build i cant believe its not working. seems almost impossible to mess it up.

 

[mitsos]

I misunderstood, I thought you had two EQs, so a direct comparison is sometimes easiest.  But from what you write, the connectivity tests imply that your unit is bypassing properly. 
With bypass working properly, the EQ is out of the circuit when either:
1. powered off or, 
2. powered on but with the EQ In switch in the OFF position (LED should also be off).

In both of these conditions the input and output XLR are connected together.

Do you get this noise if you connect the XLR cables together without the lunchbox in the middle?

 

[porkyman]

I misunderstood, I thought you had two EQs, so a direct comparison is sometimes easiest.  But from what you write, the connectivity tests imply that your unit is bypassing properly. 
With bypass working properly, the EQ is out of the circuit when either:
1. powered off or, 
2. powered on but with the EQ In switch in the OFF position (LED should also be off).

In both of these conditions the input and output XLR are connected together.

Do you get this noise if you connect the XLR cables together without the lunchbox in the middle?

yes the unit does go into bypass when its powered off. yes bypass switch works. led too. no it does not make this noise when i connect the two xlrs.

its not really a noise. its a severe clip. my ad converters have a meter and they are clipped to the max. it also jumps and clips to the max when engaged and i boost hi/lo.  when i just barely turn the boost knob it almost sounds like guitar feedback as it builds and then a really loud  clipping buzz noise.

i measured the voltage coming out and its only 1.3mv.

thanks

 

[mitsos]

its not really a noise. its a severe clip. my ad converters have a meter and they are clipped to the max. it also jumps and clips to the max when engaged and i boost hi/lo.  when i just barely turn the boost knob it almost sounds like guitar feedback as it builds and then a really loud  clipping buzz noise.

i measured the voltage coming out and its only 1.3mv.

thanks

It sounds like you have positive feedback happening somewhere.  Since it doesn't do it with the cables patched directly, that means it's in the EQ somewhere.  Did you check the amplifier stage prior to connecting them together? 
You may want to remove the PCBs from the metalwork and look over the soldering with a magnifying glass, see if there are any solder blobs or metal bits bridging pads together.

 

[porkyman]

its not really a noise. its a severe clip. my ad converters have a meter and they are clipped to the max. it also jumps and clips to the max when engaged and i boost hi/lo.  when i just barely turn the boost knob it almost sounds like guitar feedback as it builds and then a really loud  clipping buzz noise.

i measured the voltage coming out and its only 1.3mv.

thanks

It sounds like you have positive feedback happening somewhere.  Since it doesn't do it with the cables patched directly, that means it's in the EQ somewhere.  Did you check the amplifier stage prior to connecting them together? 
You may want to remove the PCBs from the metalwork and look over the soldering with a magnifying glass, see if there are any solder blobs or metal bits bridging pads together.

i already went through and retouched every solder point. ill do it again.

no i didnt check the amp stage prior. i dont really know how. i did test opamp. getting + and - 15.5v.

i am missing r9. could that be the cause? does it need to be jumpered. also i put double sided tape underneath the transformers so they're floating. that couldnt be why could it?

thanks again for the help

 

[porkyman]

ok. so i triple checked and retouched again and still couldnt find anything. decided to try scrubbing it with a toothbrush and alcohol and guess what, it worked.  lesson learned. even though there are no visible shorts or cold joints, and you use no clean solder. you still have to clean your boards.

despite my epic failures this was still the easiest build ive ever done. its the best looking too. could be the best sounding but i havent used it much yet. wanted to update before i wasted anymore of your time....

thanks again.

 

[mitsos]

Hi, sorry for not getting back, I was away for a couple of days.

. decided to try scrubbing it with a toothbrush and alcohol and guess what, it worked.  lesson learned. even though there are no visible shorts or cold joints, and you use no clean solder. you still have to clean your boards.

yes! You should always scrub your boards, it could save you days of troubleshooting strange problems. It's not so much for the rosin left on the PCB, most of that is supposed to be nonconductive/noncorrosive, but it could hide other conductive stuff that causes problems.

despite my epic failures this was still the easiest build ive ever done. its the best looking too. could be the best sounding but i havent used it much yet. wanted to update before i wasted anymore of your time....

I wouldn't call this an epic failure, by a long shot.  PLUS, you got it solved on your own, that's big right there.  We always want to get through and finish so we can hear the unit working, sometimes we get lucky and it works, but sometimes we have issues. 

Glad you found it easy to build; we tried our best to streamline the process as much as possible.

 

[Fellini]

Hey guys, wanted to chime in and report that after 1 1/2 year of trouble free operation my EQP-1S5's continue sounding as beautiful as ever. Thanks Dimitri for a great kit!

 

[hamlyf]

Hey guys,

I appear to have soldered the relays in backwards. My biggest DIY blunder to date  :-[. I'm unable to desolder them so I'll have to destroy them to get them off the PCB. I'm trying to work out which model I should get to replace them. The instructions say they are both G6K-2P-Y but I can't seem to find one that exactly matches the printed text on top of the relays going by the images on RS (the Australia Mouser). Any help would be great. Also, any tips on what damage I may have done to the circuit by putting them in backwards would be super helpful.

http://au.rs-online.com/web/

Thanks
Hamish

 

[mitsos]

Hi, I don't think you will have caused any damage to other parts.  When you had the relays reversed, the contacts that received power are the normally open contacts so it would be an open circuit. So, the good news, is there is probably no further harm done.

It seems the instructions are wrong though, the relays are G6K-2P.  I think Niels can help you with them.

Good luck with the rest of the build!

 

[Trench Recordings]

build doc reads funny to me.

Do I omitt C34 and C33 on the filter board ? or just C34 ?

 

[mitsos]

Yes, maybe the text could use revising.

Please follow the BOM in the manual, only omit C34.

cheers!

 

[kosi]

Hi to all,
I finished mine yesterday , while waiting for a friend (who didn't show up) in 4 hours.
Very nice build, I struggled a bit with some pins of the carnhills underneath the pots, but everything worked out fine.
After my first start, I had an oscillation going on til I recognized, that i had the cables from both transformers the wrong way.
Black was, where Blue belonged, I guess my brain translated BL to black automatically, but the real Black is BK...
I used the 120pF polystyrene btw.
GAR2520 by Capi

The sound is excellent, did a short comparison with my ezP-1a and the differences, especially in the highs, are negligibly small.
Bass is tighter in the 1S5 than the ezP-1a, which is exactly the combination, what I was hoping for.
Now I need one more...

Thanks to mitsos und Niels for this brilliant kit  ;D

 

[mitsos]

Very nice build, I struggled a bit with some pins of the carnhills underneath the pots, but everything worked out fine.

Yes the grayhill switch pins are very small and close together and the size of the 500 series module doesn't leave much room for error, but with care and a narrow tipped iron it all works out! 

After my first start, I had an oscillation going on til I recognized, that i had the cables from both transformers the wrong way.
Black was, where Blue belonged, I guess my brain translated BL to black automatically, but the real Black is BK...

that'll do it!

The sound is excellent, did a short comparison with my ezP-1a and the differences, especially in the highs, are negligibly small.
Bass is tighter in the 1S5 than the ezP-1a, which is exactly the combination, what I was hoping for.
Now I need one more...

Thanks to mitsos und Niels for this brilliant kit  ;D

Thank you for the kind words! Enjoy your EQ!

 

[dmlovett57]

Got my kit and started building.  The values for R1 and R3 are reversed on the BOM vs the PCB.  Which value goes at the back of the PCB, and which goes next to C13?

 

[mitsos]

Yes, R1 and R3 got their numbering mixed up on the PCB!  The resistance values are correct as written on the PCB, though. 

Sorry for the confusion! 

good luck with the rest of the build!