What sonic differences to expect if upgrading Paramount 300B caps?

[rbc3]

I've been reading about people upgrading the .1uf interstage coupling capacitor with a Vcap or other (assume the TFTF .1uf 600V Vcap) and the parallel feed capacitor to a Mundorf silver gold oil (seen a lot of different uf from 3.3uf to 5.6uf and apparently must be greater than 650V rated).

What isn't clear to me is what sonic differences are gained from making these cap upgrades in a Paramount 1.1 300B?

Are there other common upgrades and how do they benefit the sound?  I have to be honest, the stock amps sound fantastic to me and I'd be blown away to realize even greater sonic improvements.

-Robert

[Paul Birkeland]

What isn't clear to me is what sonic differences are gained from making these cap upgrades in a Paramount 1.1 300B?

They are fairly minimal.  For what it's worth, our demo system uses Paramounts with all factory components.

Are there other common upgrades and how do they benefit the sound?  I have to be honest, the stock amps sound fantastic to me and I'd be blown away to realize even greater sonic improvements.

I would recommend playing around with nicer 300B's.  Yes, it's expensive, but you will hear it!

[rbc3]

Thanks Paul.  Good to know.  I kind of wondered since people weren't really articulating significant differences.  Beyond the stock EH 300B tubes that came with the Paramounts, I now have a matched pair of Svetlana "Winged C" 300B from 2003 and a matched pair of KR VV300B from the 1990s.  The sound difference between the EH and the other two NOS sets is quite significant.  The difference between the Svetlana and KR a little closer.  I need some more listening time on all of them to be able to articulate.  So far, I think the Svetlana Winged C might be my favorites and curiously enough it looks a LOT like a Western Digital 300B.

I don't have any Chinese tubes yet, but I'm sure I'll get the urge at some point.  I figure one set from each of three Chinese factories producing them would be interesting to compare: PSVane, Shuguang, and TJ Full Music.

[Doc B.]

Western Digital 300B

I looked for a file about that tube on my Western Electric hard drive, but I couldn't find anything. The Svets were one of the early attempts at a 300B redux and were indeed designed to be like the Westerns physically. I recall jcmorrison telling me that had quite a time figuring out getting the filaments to hang properly.

[Chris65]

I don't have any Chinese tubes yet, but I'm sure I'll get the urge at some point.  I figure one set from each of three Chinese factories producing them would be interesting to compare: PSVane, Shuguang, and TJ Full Music.

Although different brands, do they all come from the same factory? I recently bought a pair of the 'cheap' PSVane HiFi 300B & quite happy with them, although I don't have much experience with 300B to compare.

[rbc3]

DOH!  I typed Western Digital...   Can you tell I'm in the computer industry?  Of course I meant Western Electric.

From what I've read, Shuguang, TJ Full Music, and PSVane are three separate tube factories in China.  PSVane bought out the Guiguang factory and now operate separately from Shuguang.  Sophia, TJ, and Full Music tubes are made at the TJ Full Music factory.  Golden Dragon, Treasure, Black Beauty, Valve Art are all made at the Shuguang factory.  I think only PSVane branded tubes are made at the PSVane factory.

Other 300B factories that I know of are:
KR - Czech Republic (bought out Vaic AVVT)
Emission Labs - Czech Republic
Reflektor - Russia (makes Electroharmonix, Sovtek, and Genelex Gold Lion)
Svetlana - Russia (AKA Winged C)
JJ - Slovakia
Elrog - Germany
Takatsuki - Japan

[Chris65]

Thanks for the information.

Sovtek & Svetlana don't seem to be producing 300B anymore.

[rbc3]

In a conversation with a tech from an online shop that sells hifi parts, he recommended the following for Paramount upgrade.

"The interstage coupling should be increased to 0.22uF.  I would use a Jupiter Copper there.  I have no problems with 3.3uF to 4.7uF for the para feed, but 600VDC is more than sufficient.  Again, I like the Jupiter Copper here.  I would also recommend using a Mundorf TubeCap for the 47uF cathode bypass."

I'm curious about his recommendation for .22uF interstage coupling cap.  That's different than I've read in the forums here.  Also is 600VDC OK for the parafeed cap?  If I do go for a 4.7uF parafeed cap, how will it change the sound?  And lastly, how would replacing the cathode bypass change the sound?

Thanks for any advice.

-Robert

[Doc B.]

It won't hurt anything, but the interstage coupling cap does not need to be increased to .22uF - unless maybe you have an excess of .22uF caps in stock.

This stuff is like wine. Just because some guy tells you he likes it, it doesn't mean that you won't want to pour it down the sink. You really have to try the stuff yourself and see. If what you are looking at has you hesitant because of the price, skip it. There's plenty of pleasure to be had and knowledge to be acquired from your own experiments with inexpensive components.

For what it's worth I'm building a pair of Paramounts for myself this week. Peebs and I looked around at what was available and decided to go with a V-Cap for the interstage cap and to try a Solen metallized silver cap for the Parafeed coupling cap. That said, I have been happy with the stock caps in my system for about 7 years.

[Paul Joppa]

I prefer the 0.1uF interstage value on technical grounds, having to do with recovery speed when transient peaks cause momentary grid current. Many people think "the bigger the better"; I am not one of them.

[johnsonad]

Please listen to PJ and Doc B as they are the team who designed this amp. Upgrades are fun and if you read through my threads, I've tuned BH gear for a few years. In the beginning, you are susceptible to hype and some is well founded while others and most is personal opinion based off of their system and listening preference. What I'm trying to say is let your ears be your own best friend and your system sounds like nobody else's.  What worked with my horns doesn't work with my 755a's and room changes make more of a difference than any component I've swapped.  For me, V-Caps are amazing as interstage caps but take forever to break in. PF caps too make a differnce but both need to be tailored to your system and your room.  I finally found what worked well for my system by using Graingers system of alligator clips and listening sessions. Start cheap and go from there. You may be surprised at what works for your system! Be patient and follow what sound good to you above what others say!

[mhardyman]

From what I've read, Shuguang, TJ Full Music, and PSVane are three separate tube factories in China.  PSVane bought out the Guiguang factory and now operate separately from Shuguang.  Sophia, TJ, and Full Music tubes are made at the TJ Full Music factory.  Golden Dragon, Treasure, Black Beauty, Valve Art are all made at the Shuguang factory.  I think only PSVane branded tubes are made at the PSVane factory.

I have been running the TJ 300B/n so-called mesh plate for years and they are my go to tube.  I have a pair of the Psvane 300B T-series Mark II and they are impressive.  Those are the grey bottles.  The TJ's pull off a slightly more authoritative bass.  The Shuguang 300B-98 bottles are actually quite good and considering that they are the cheapest out there quite amazing!

[rbc3]

Well despite everyone's really great advice to go easy on cap upgrades, I bit the bullet and bought some expensive caps.  Here's what I bought.

Interstage coupling: Jupiter Copper 0.1uF 600VDC
Parafeed: Mundorf Supreme Siver/Gold/Oil 4.7uF 1000VDC
Cathode bypass: Mundorf Tube Cap 47uF 600VDC

Some day I might try a teflon cap for the interstage like a V-cap TFTF or CuTF.  And who knows I might go totally crazy and blow even more money on a Jupiter Copper or a Duelund Cast PIO Copper for the parafeed.  But the above seemed like it was enough big money to spend without going too extreme.

Just to be overly sure... The parafeed cap goes across 1U and 6U terminals.  The interstage coupling cap goes across the 9U and 7U terminals.  And the cathode bypass cap goes across 10U and 5U terminals.

Also Aaron, you mention a Grainger method of alligator clipping in caps for testing the differences.  Is that anything more than what it sounds like?  I suspect that just means using alligator clips to install the caps to the terminals instead of soldering them in to test various combinations of stock and new caps.  Then when the final decision is made, solder them in.

[rbc3]

Oh I wasn't planning to stick my fingers in there when the power is on.  Is it even OK (safe for the amp) to disconnect a cap from the terminals and connect a different cap to the terminals when the amp is powered up?  If so, maybe I'll pick up a couple of 1 pole 2 position switches and connect them with alligator clips.  That I can switch back and forth while something is playing and really hear the difference.

[Grainger49]

Look at reply #10 in the thread linked below.  It shows how I rolled Eros Output caps.  There is only one signal path cap in the Eros.

http://bottlehead.com/smf/index.php?topic=2878.0