12n and 15n capacitors for the gpultec

[migidee]

I found all the wima values at mouser for the poly caps but they don't make any in the 12n and 18n values in the high frequency.  Could I replace them with the 10n and 15n like in the original pultec without affecting the frequencies?  Or would it be better to use a different brand for just those 2 capacitors?

 

[shabtek]

parallel some 1n caps.
frequency will be affected.
will you notice?

 

[migidee]

parallel some 1n caps.
frequency will be affected.
will you notice?

I just want it to be close to the original pultecs frequencies, but unless I had two wired diffirently for an ab test then no I wouldn't notice

 

[creal]

hi

You can use the Panasonic Caps or Xicon.
http://www.banzaimusic.com/Polypropylene/

I use this cap in my Gpultec

 

[migidee]

hi

You can use the Panasonic Caps or Xicon.
http://www.banzaimusic.com/Polypropylene/

I use this cap in my Gpultec

Yeah, that is what I meant in the original post.  I was going to use the panasonics, but I wasn't sure how critical it was to match the brand of caps for uniformity of sound, especially in the same filter section?  Or would it adversely affect the frequencies by changing the values?(especially when in series with inductors.  I can calculate an RLC circuit but I have no clue how it pertains to frequency)  I wanted to use wima polys in the entire circuit, but wima only makes them in 10n and 15n.  As shabtek mentioned, I could always parallel the two caps with some 1n's but the short wima leads and physical size don't make it very easy. So my question is, is it better to have the correct values or the same brand?  My goal is to keep the frequencies as close to the original as possible.(yes I know they were adapted to six frequencies in the high band and added some in the low band) Speaking of which, does anyone know what the new frequencies are?

I see 20hz, 30hz, ?, 60hz, 100hz, ?  on the low band.

And ?, ?, ?, 10khz, 12khz, 16khz in the high boost

And ?, ?, 10khz, ?, 5khZ on the high cut.

I can guess what goes in the blanks but does anyone know for sure?

 

[snipsnip]

i dont recckon you'll be able to hear any appreciable difference, but opinions on these things vary.

Why dont you buy & try?

 

[migidee]

i dont recckon you'll be able to hear any appreciable difference, but opinions on these things vary.

Why dont you buy & try?

I plan on it, but it would be less work if I knew how to calculate freq responce by adjusting the cap and inductor.  Also, I do believe that great eq's are great because of their frequency curves, as well as other things, so it does make a little difference.

 

[snipsnip]

if you are trying to make the most authentic pultec clone possible the gpultec probably isnt your best bet

P.S - there is a pultec help thread for all this kind of stuff.

 

[lassoharp]

but it would be less work if I knew how to calculate freq responce by adjusting the cap and inductor.

You want to know the center frequency.  Online calculators make the number crunching easier.

http://sim.okawa-denshi.jp/en/Fkeisan.htm


Being able to calculate this will allow you to verify what's going on with existing schematics and will free up your design choices. . .

 

[migidee]

if you are trying to make the most authentic pultec clone possible the gpultec probably isnt your best bet

P.S - there is a pultec help thread for all this kind of stuff.

I am trying to build the the MOST COST EFFICIENT pultec clone.  Getting as close to the pultecs freq response as possible is icing on the cake.  Most of the more accurate pultec clones are around $800 a channel compared to the sub $400 I plan on spending on the gpultec, which gets me more than halfway there for less than half the price! And perhaps I missed it, but this was not discussed in the help thread or meta. 

 

[migidee]

but it would be less work if I knew how to calculate freq responce by adjusting the cap and inductor.

You want to know the center frequency.  Online calculators make the number crunching easier.

http://sim.okawa-denshi.jp/en/Fkeisan.htm


Being able to calculate this will allow you to verify what's going on with existing schematics and will free up your design choices. . .

very interesting.  This appears to be what I am looking for, but I have not fully wrapped my head around it yet.