mustards: can I use 160V instead of 400V??

[young flower]

Hi

I´m going to build a 69 Superlead soon, using the Metroamp 100W kit instructions.
I´m going to use Mullard Mustard capacitors for the board (from kurtsequipment BTW). I´ve got all the caps I need for a Superlead now except:
1x0,022 uF
1x0,0022 uF
(2x0,68 uF (which are practically impossible to get now - I´ll use SOZOS instead of these))

Since it´s a lot easier to find the 160V ones on ebay, I was wondering if I could use 160V versions (at least one 0,022 and one 0,0022, as listed) for a Superlead board??
Can anybody give advice on that? It´s my first amp build.

Thanks
YF

[6burgh]

NO! Not for coupling caps... there the 0.022u caps you see in the layout that connect to one end of the 100k resistors and on pins 1 and 6 of the preamp tubes and then to the volume pots. There is significantly more voltage present here than 160v.

The 160v caps are fine for cathodes. They're the "yellow" wires connecting from pins 3 and 8 to ground with a resistor and cap in parallel. 400v rated caps are a must for couplers. Good luck in your search... I bought a set from this guy and they were top notch. Hope this helps!

http://www.ebay.com/itm/MULLARD-MUSTARD ... 1e7575e67d" onclick="window.open(this.href);return false;

[6burgh]

Oh, and check Valvestorm for the 0.0022u mustard caps. Robert has some I believe... I just purchased a few. And for the cathode caps, consider looking at the Suhr SL68 and other builds... many find the polypro and other types great here. All personal preference in the end! Good luck!

[Haze13]

The brand of the 2x0,68 uF caps - will not give you the better tone, but the 5% or less of tolerance - will. Save the money on those. Polyester 5% (wima, philips, xicon...) will do job. For the 0.022uf caps use the best you can

Polyester caps can change the tolerance and perfomance as they heat up. Polypropyle - are more stable. That's why amps with polyester caps sounds much better after 10 - 15 of working.

[young flower]

Thanks for the advice guys: So far, I got the 0,0022 uF Mustards (got 2 - you can always use a spare mustard later) from an ebay seller in the Netherlands - I´m located in Austria, Europe. Batch code for those is B3S and C3S (according to seller - they didn´t arrive yet). So I guess these are from 1973. All my other ones are from the same seller you bought from 6burgh and they are from 1966 apparently. At the time I bought from him, I thought I´d build a Superbass and therefore wouldn´t have needed the missing values I´m searching for now. But I decided I better get all the parts for a SL conversion now, so that I can easily do it later if I don´t like the SB tone on my plexi.

The brand of the 2x0,68 uF caps - will not give you the better tone, but the 5% or less of tolerance - will. Save the money on those. Polyester 5% (wima, philips, xicon...) will do job. For the 0,022uf caps use the best you can

Thanks for the advice. But I think I´ll still go on a "spending spree" for those and take the 2 SOZOS for 0,68uF .
I´m trying to get a good old Mustard for the last missing 0,022 uF.

[Roe]

only where the voltage is less than 160v:
-cathode bypass caps
-PI input (possibly also indirect input)
- presence
In low voltage amps, the tonestack should also work