OT: Russian bypass caps

[Elitopus1]

Ok, I'll bite.
Why are you bypassing the X-over caps?

The second poster in this thread explains it well.

Uncharted Crossover Design Waters - Techtalk Speaker Building, Audio, Video Discussion Forum

In crossovers it started out to bypass electrolytics but then people started bypassing poly caps too. Some people even bypass their bypass caps.

The idea is the smaller cap improves VHF performance that the bigger capacitor can't let through because of ESR or inductance. Its the path of least resistance for those frequencies.

For example in my 604G crossovers I used motor run caps. They are good but can be improved on. Bypassing those with a small value film cap helps to clean up and improve the HF.

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Seems like a lot of different opinions on bypass caps. I have some Russian K42Y-2 0.1uf 600V caps on the way. Nobody has mentioned the K42Y-2 series, are these not the type that I need?
For all the hubbub about Russian caps, there seems to be very little actual info on them except on how they are constructed. No real info on the best usage for each series.

BillWojo

I haven't tried those caps but would be interested to hear your opinion when you get them. They are really reasonable in price too. Ussr-tubes has them in different values from .015uf up to 1uf and 250v up to 1600v

[LowOhms]

I have used all three of the above caps. The K75-10's are the best large value caps that I've used in a passive crossover. The FT-3 Teflon's are great bypass caps for the K75-10's. The K40Y PIO small values (3300pf) are very much better than the WIMA's. I had WIMA FPK2's in my Marchand XM44 and the K40Y's put them to shame. Both the FT-3's and K40Y's are great for bypass caps and will improve any setup. Just my opinion in my systems YMMV. I have since replaced the K75-10's with Duelund Cast Tinned Foil caps and will never go back, the cost benefit is up for the individual to determine but the benefit is sure there.

I never suggested WIMA FKP2s, did I . FKP1s. I liked your post. It takes a MINIMUM of 3 bypass caps, and up to 7 or 8 , in any one location, to get it right !! SO, its not just cap types, but cap VALUES also, each play a different part of the spectrum.

The smaller uF values need to be explored, assuming one has a well implemented wide-band system to reliably make such determinations.

Jeff

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Ok, I'll bite.
Why are you bypassing the X-over caps?

Thats easy, no ONE capacitor does the entire audio spectrum in a LINEAR and optimum way.

The Cs in my DIY A7-800 crossover use about 4 caps in each and every "C" position . My tube amps, with an all-film-cap supply, may use 3 to 8 bypasses at each " C " location.

Its determined by ear, listening to music, if your system is well implemented, great amps, wiring, etc..


Jeff Medwin

[RonSSS]

Got it.

So read that article, then searched a bit on DIY Audio forum.
I gather two camps.......
So in the end it's a try it and see. Big time experimenting.

I once tried Zen caps from North Creek Audio. Company now defunct.
They were polypropylene.

Used them in my Duplexes, just the stock Xover.
Hated them.

So that's the only experimenting I've ever done with Xover caps.
I put them back to stock.

My M19's Xovers are stock.

PP 300B transformer coupled tube amps Jeff.
I designed and built them.

No fancy caps in them either. Just off the shelf parts from the Tektronix stockroom.
I worked there for 38 years.

Ron

[LowOhms]

Got it.

So read that article, then searched a bit on DIY Audio forum.
I gather two camps.......
So in the end it's a try it and see. Big time experimenting.

I once tried Zen caps from North Creek Audio. Company now defunct.
They were polypropylene.

Used them in my Duplexes, just the stock Xover.
Hated them.

So that's the only experimenting I've ever done with Xover caps.
I put them back to stock.

My M19's Xovers are stock.

PP 300B transformer coupled tube amps Jeff.
I designed and built them.

No fancy caps in them either. Just off the shelf parts from the Tektronix stockroom.
I worked there for 38 years.

Ron

Tektronix !! My first audio Mentor, Robert W. Fulton of Minneapolis ( 1925-1988 ) was a BIG fan of Tektronix scopes, and he knew how to use them well !! Ever hear of Robert??

A P-P 300B will have a "naturally" wider bandwidth than any SET amp.

In a SET amp, proper bypassing is mandatory, if you " want to have it all ". VERY few build SETs right, usually too cheap and too uninformed to build it as the music requires it to be built. Our ALTEC crossovers are also single ended !!

Jeff

[Elitopus1]

No fancy caps in them either. Just off the shelf parts from the Tektronix stockroom.

I would imagine the components they use in their scopes are on par with many audiophool grade caps and components. You probably have some good quality parts in there

[SD-50]

I would imagine the components they use in their scopes are on par with many audiophool grade caps and components. You probably have some good quality parts in there

I have a Tektronix scope like this one on ebay. The build and quality of components is of the very highest level from that period. I take a few pics tonight and post them later.
Tektronix 545 Oscilloscope | eBay

[RonSSS]

Haven't heard of Mr. Fulton Jeff.

It was always handy to just walk to the stockroom and get parts for personal projects. Back in the good old days when it was actually encouraged.
I'm sure the parts are high quality. Not real sure if they would be considered esoteric.
As times changed, they threw away a lot of the old stuff. So it was pretty good pickings.
Scored a lot of high grade tubes as well.

I have a 545 scope. it doesn't work, but I have the manual, and know what the issue is. Just haven't gotten around to fixing it.
The insides of those are works of art and mechanical marvels.
Again, the good old days!

Of course my test bench is chocked full of Tek test equipment. I'd bet it will all still work when I'm long gone.

Ron

[BillWojo]

I have a friend that grabs old Tek scopes for the tubes. I have yet to see any electronic gear that even comes close to the build quality of those scopes. If they built them today like that, only the government could afford them. The main power transformers are a thing of beauty with cast aluminum end bells. Just over the top.
By the way, if you ever scrap one, grab the sheet metal shield that wraps around the CRT for shielding, it's made of Mu-Metal.
I have an old Tektronix 465M scope that still works.

BillWojo

[RonSSS]

I worked in the Spectrum Analyzer group. Started in 1977.
Technician, then engineering tech, new product development tech and finally a project manager in the Microwave Technology Organization.
Worked in TV products for several years as well.

I was the development tech for our 8-18ghz YIG oscillator. And of course it went in a mu-metal can!

All scopes are made in China now. Thanks to Danaher Corp who bought Tek in 2007. No longer the same great company it once was.


We apologize for getting off topic!

[SD-50]

Ok, last OT post. Some pics of my Tektronic scope, gold plated boards with German and Dutch tubes.