G-PULTEC problems, please help!

[ding]

This is what I ended up doing.

 

[spudstyle]

Hello guys,

I plan to make 2 G-Pultec units. I will buy PCB at PCB Grinder but I need some details about capacitors:

- What's lead spacing for 3n3, 6n8 etc ? And for the 330n, 470n, 4u7 etc ? Is it 7.5mm and 10mm ?
- Wich kind of caps I need ? Wima MKS2 ? MKS4 ? What is the best ?
- What is the voltage for small caps (3n3 to 100n) ? 63v ? And 250v the others ?

Last question: Where I can find 3n3, 6n8 and 12nf caps in Europe ? Can't find @ Farnell or RS !

Thanks for your help

 

[ding]

Hello guys,

I plan to make 2 G-Pultec units. I will buy PCB at PCB Grinder but I need some details about capacitors:

- What's lead spacing for 3n3, 6n8 etc ? And for the 330n, 470n, 4u7 etc ? Is it 7.5mm and 10mm ?
- Wich kind of caps I need ? Wima MKS2 ? MKS4 ? What is the best ?
- What is the voltage for small caps (3n3 to 100n) ? 63v ? And 250v the others ?

Last question: Where I can find 3n3, 6n8 and 12nf caps in Europe ? Can't find @ Farnell or RS !

Thanks for your help

The lead spacing is in Don Audio's excel file. What WIMA sounds best is a never ending debate. Filter caps can be 63v and up. good luck.

 

[spudstyle]

Ok thank you ding.

Anyone know where I can find the 3n3, 6n8 and 12nf in France or Europe ? Thanks

EDIT: is it better to use Styroflex ? I've found the 3n3, 6n8, 12 and 18 in France ! And it's better to use resistors like Vishay CMF55 series ?

 

[dipfrik]

Mouser

3n3  = 80-PHE450MK4330JR17T
6n8 = 505-FKS36800/100/10P
12nf = 5989-250V.012-F

Cheers, Sven

 

[ding]

Ok thank you ding.

Anyone know where I can find the 3n3, 6n8 and 12nf in France or Europe ? Thanks

EDIT: is it better to use Styroflex ? I've found the 3n3, 6n8, 12 and 18 in France ! And it's better to use resistors like Vishay CMF55 series ?

Give them a try. I personally like wima on the low and orange drop on the high but it is DIY so give it a go.

 

[spudstyle]

Ok, so if I want something sweet on the high, wich is better ? Wima, Orange drop or Styroflex ? I can't try every caps, not enough money

EDIT: do you think Cinemag CML-150T is better sounding than Toko inductors ? I just need to change some caps but it's not a problem.

 

[ding]

Ok, so if I want something sweet on the high, wich is better ? Wima, Orange drop or Styroflex ? I can't try every caps, not enough money

EDIT: do you think Cinemag CML-150T is better sounding than Toko inductors ? I just need to change some caps but it's not a problem.

What sounds better depends on individual taste. I cannot/will not go into that. You will just need to experiment and find what you like. that is the best part of DIY, else just buy a used pultec from evilbay and call it a day. As far as inductors go there is something to be said about a multi-tap inductor with the proper ferrite. My taste right at this moment is that I like WIMA on the lows, orange drop on the highs, and custom inductor (hand wound or other wise) but that is what sounds good to my ears right now. Winding your own multi-tap is easy if you have a meter that measures in mH. I have built one with toko, one with hand wound, and one with cinemag and I do prefer the hand-wound/cinemag but that could just be mystical self mental masturbation than anything else. I thought toko sounded pretty good too. If you are going the cinemag route you need to call Cinemag and ask them to wind you a G-Pultec inductor 22,69,169,269. All in all, if you just use Wima and toko and everything thats in the BOM you will have a nice sounding piece of equipment that you will enjoy for many years. Don't get caught up too much into what caps are good. those are things that are not important. Use Polystyrene, polypropylene or polyester for the filter and audio portions of the main board and you will get a good sound.  ;D

 

[APL]

I also used mixture of WIMA and orange tops. I bought from Banzai Music in Berlin who had a good range.

However I found it difficult getting all WIMAs with correct lead spacing to fit  board. The WIMA leads are also very short and you cannot always bend them to fit. Also the larger value WIMAs I bought were too wide to fit in the space.

I also need to paralell some orange tops to get correct values

The ideal WIMAs and orange tops may be out there but I didnt find them.

 

[spudstyle]

Thanks for your answers guys. I found all I need except the 2u2 in 7.5mm. My BOM is ok

Do you know if the original frequencies knobs exist in chinese model ? I found the original but it's $10 for a knob ! I found all other knobs, volume, off/on and the chickenhead (Tube-tech style no dakaware).

 

[ding]

no problem  I love old knobs so mine are all dakaware. on my last one I spent $120 just on knobs.  enjoy your new toy.

 

[spudstyle]

I got a new question

I want to change some frequencies on the lows. I've seen that we have 20-25-30-40-60 and 100 Hz but I don't want the 20 & 25 Hz, I want to make something like 30-40-60-80-100 and 120 Hz. How can I calculate the frequencies on this filter ? I understand how to calculate the Hi filter (LC) but not the Lo :/
Sorry, I'm not electronician ^^

 

[gyraf]

The frequencies (on all but HI-Boost) are proportional to the capacitors, as they are first order RC filters. Larger capacitors, lower frequencies. Try out some, and see what you like.

Not much to be gained IMO by changing frequencies, that's not where the magic works...

Jakob E.

 

[djob]

hi all!
money saving question...
here it's 230v mains power, and i happen to have a 230v:6.3v valve transformer for the heater, so can i skip buying the stacked transformers and just run straight from the mains power acording to rest of the gpultec psu schematic.

cheers

 

[Harpo]

money saving question...
here it's 230v mains power, and i happen to have a 230v:6.3v valve transformer for the heater, so can i skip buying the stacked transformers and just run straight from the mains power acording to rest of the gpultec psu schematic.

Brilliant approach against overpopulation.
Just don't run straight from mains power.

 

[spudstyle]

The frequencies (on all but HI-Boost) are proportional to the capacitors, as they are first order RC filters. Larger capacitors, lower frequencies. Try out some, and see what you like.

Not much to be gained IMO by changing frequencies, that's not where the magic works...

Jakob E.

Ok but don't understand how to calculate the low filter. What caps values I need if I want 20-30-40-60-80-100 Hz in the flow filter ? Thanks

 

[ding]

The frequencies (on all but HI-Boost) are proportional to the capacitors, as they are first order RC filters. Larger capacitors, lower frequencies. Try out some, and see what you like.

Not much to be gained IMO by changing frequencies, that's not where the magic works...

Jakob E.

Ok but don't understand how to calculate the low filter. What caps values I need if I want 20-30-40-60-80-100 Hz in the flow filter ? Thanks

https://www.google.com/#q=RC+filters+calculator 

 

[spudstyle]

The frequencies (on all but HI-Boost) are proportional to the capacitors, as they are first order RC filters. Larger capacitors, lower frequencies. Try out some, and see what you like.

Not much to be gained IMO by changing frequencies, that's not where the magic works...

Jakob E.

Ok but don't understand how to calculate the low filter. What caps values I need if I want 20-30-40-60-80-100 Hz in the flow filter ? Thanks

https://www.google.com/#q=RC+filters+calculator 

I know google and I got a calculator but I don't understand the filter in the schematic. I'm not electronician. Where is the filter ? This is the filter between 10k resistor and "2u2-1u-680n-etc" ? Please explain me, I don't ask you to do the job, I just want to understand
if you think otherwise, it's because my english sucks lol

 

[who]

inductors and the caps make the filter.

Don

 

[gyraf]

..but the inductors are only involved in the high-boost section.

spudstyle - it is all in the schematic. If the schematic does not make sense to you, try the mentioned empiric approach:

Larger capacitors, lower frequencies. Try out some, and see what you like.

Jakob E.