Build Thread:PQD2

[Vac11]

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.

 

[Lieto]

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

 

[Gustav]

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

 

[Gustav]

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

 

[Lieto]

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

 

[Gustav]

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

 

[Lieto]

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

 

[relurelu]

  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.

 

[Gustav]

  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

 

[rprimmett]

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.

 

[leo-666]

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...

 

[Gustav]

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

 

[leo-666]

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 ?

 

[Gustav]

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

 

[leo-666]

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 )

 

[Gustav]

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

 

[leo-666]

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.

 

[rprimmett]

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

 

[rprimmett]

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.

 

[rprimmett]

I think I got it figured out following this diagram, pin 6 of the ll5402 is pin 8 on the xs1100