Request details on how to apply k75-10 Russian bypass capacitor

[joej]

At this point I am not planning on doing much additional mods beyond the stock Crack/Speedball, but I was curious about one discussion I found on the forum regarding adding k75-10 Russian Mylar pio bypass capacitor to the 100uf coupling capacitors. I have a stock Crack/Speedball and would appreciate information on exactly how to apply this mod (which hopefully is fairly straightforward).

http://bottlehead.com/smf/index.php?PHPSESSID=d3f476q9jg1qsck6pso2tncft2&topic=6862.msg66826#msg66826

thanks

 

[JamieMcC]

Hi essentialy you take a short fly lead from each end of the bypass capacitor and then connect a end of each lead to one of the terminals of the capacitor you are bypassing. Be warned the K75-10 can take a while to burn in so some patience is required with them.

I have only tried bypassing 100uf film caps with them myself but it would be interesting to hear what effect they have when used with the electrolytics. They had quiet a unique sound very musical if a bit rolled off on the top end when used with the 100uf films but adding some russian teflons bypasses as well helpded remedied that.

Have fun experimenting

 

[joej]

The output capacitor 100uF 160V electrolytic capacitor is soldered to 6U (striped side) and 7U (non-striped side, orientation is critical). The second 100uF 160V  electrolytic capacitor is soldered to striped 10U and non-striped to 9U. The speedball upgrade doesn't affect how these output capacitors are installed, but does require bending them out of the way.

So if I understand what is meant by 'bypass' this meas that the original 100uF 160V capacitors are not removed or altered. The two Russian K75-10 250V 2.2uF PIO capacitors are added one at the junction of 6U and 7U and one at 9U and 10U.  There is no directionality to the PIO capacitor.

Perhaps that is not the proper wiring for this bypass?

Clarification is appreciated.

 

[Rocketman248]

You are correct.  You're adding the capacitors to the same terminals, putting the two capacitors in parallel in the circuit.

 

[joej]

That's what I thought. Nothing complicated. I see now that some of Crack/Speedball custom modifications being done are simply swapping out stock components with higher end components, or making minor alterations to the circuit by adding another component in parallel (bypass).  This particular mod sounded interesting in order to bring some richness to the mids without losing too much of the benefits of the speedball upgrade. The cost is more than a cup of coffee after paying for shipping of two k75-10 capacitors from eastern Europe as there doesn't seem to be any local suppliers.

I plan on placing an order and will post pictures and impressions of the mod down the road.

thanks for the responses

 

[joej]

Easy mod. I haven't made any permanent changes with mounting brackets in case I prefer going back to the stock Crack/Speedball. With 100 hours of burn in I will reserve judgment. There is a noticeable change in sound. I do like the stock crack/speedball, so time will tell if this is an improvement or not. Less expensive experiment than rolling more expensive tubes. Plenty of room for two Russian k75-10s.