[therremans]

Those are really good caps, but you're going to need a big shoehorn. Lengthwise they can probably be made to fit (1/8" longer than the stock caps), but 3 of them side by side (per channel) will take 4.25" and the stock caps only take 2". I don't think you want to go with any less total capacitance (ie: fewer caps), as I've been told that more capacitance there would be better than even the stock 30 uF/channel.

good catch, thanks. I hadn’t opened up the amp and taken measurements yet but clearly too wide. But now that I know the 2” per channel, I can look at another options.

If 2"x2" works for each channel. I could use one of their 33uf per side
ClarityCap Capacitor 33uF 250Vdc CSA Series USD $27.95 (L-50mm W-52mm)

I could also maybe fit one of these,
ClarityCap Capacitor 0.33uF 630Vdc CSA Series (1% of 33uf)

 

[bcowen]

 

[bcowen]

good catch, thanks. I hadn’t opened up the amp and taken measurements yet but clearly too wide. But now that I know the 2” per channel, I can look at another options.

If 2"x2" works for each channel. I could use one of their 33uf per side
ClarityCap Capacitor 33uF 250Vdc CSA Series USD $27.95 (L-50mm W-52mm)

I could also maybe fit one of these,
ClarityCap Capacitor 0.33uF 630Vdc CSA Series (1% of 33uf)

Not trying to rain on the parade (I'd love to replace those caps!), but that 2" x 2" won't fit either. The footprint of the existing 3 caps (per channel) is 1 3/8" (35mm) x 2" (51mm). And there's not much wiggle room beyond that -- maybe + 1/4" each way, but without relocating some other stuff that's about the extent of it. That's what got me interested in those Vishays as they will fit in the footprint of the existing caps.

 

[therremans]

Not trying to rain on the parade (I'd love to replace those caps!), but that 2" x 2" won't fit either. The footprint of the existing 3 caps (per channel) is 1 3/8" (35mm) x 2" (51mm). And there's not much wiggle room beyond that -- maybe + 1/4" each way, but without relocating some other stuff that's about the extent of it. That's what got me interested in those Vishays as they will fit in the footprint of the existing caps.

Good to know. You’ve done the homework and I pulled the second measurement out of you. Consider my parade rained on. I’ll keep searching or accept Vishays.


Are the resistors on the pcb only for the preamp output signal?, if so, I could remove them.

 

[bcowen]

Good to know. You’ve done the homework and I pulled the second measurement out of you. Consider my parade rained on. I’ll keep searching or accept Vishays.


Are the resistors on the pcb only for the preamp output signal?, if so, I could remove them.

The blue blocks (white arrows)? Those are the .47 uF caps for the preamp out. I suppose they could be removed, although I'm not knowledgeable enough to know what that might do to the circuit (if anything). But doing that would increase that available space from 1 3/8" to close to 2" if everything is placed just right. Of course the next problem now rears its ugly head -- there's only 1 3/8" of space between the circuit board and the bottom plate and that 33 uF Clarity cap is a little over 2" in diameter. Sigh.

 

[therremans]

To quickly go back to the French Thomson 6080.. I let it burn in all day, for about 16 hours and popped in a Ken-Rad late this evening. Nice combo.. The tube now sounds a little more versatile after the burn in and with this pairing. I would assume several other output tubes with a low-end or mid focus would be similar. It retains its nice clarity. Yeah, it still lacks the texture and soundstage of a premium 6080.. and it still has a lighter bottom end. I would still easily recommend it for an affordable and guys new to the hobby. I like it so much I will actually keep it. It's just an all around good sounding tube. Much more enjoyable than the RCA was for me early on, but I would still recommend the RCA or Svetlana if low end is a priority.

 

[therremans]

The blue blocks (white arrows)? Those are the .47 uF caps for the preamp out. I suppose they could be removed, although I'm not knowledgeable enough to know what that might do to the circuit (if anything). But doing that would increase that available space from 1 3/8" to close to 2" if everything is placed just right. Of course the next problem now rears its ugly head -- there's only 1 3/8" of space between the circuit board and the bottom plate and that 33 uF Clarity cap is a little over 2" in diameter. Sigh.

I forgot about those big blue capacitors. It really sounds like the height limitation will restrict us. I thought it would be fun to fit real foils. let me know what else you think of.

Do you think using hifi resistors like z-foils on the shunted pot would make much of a difference? Also there are three resistors coming off of the 6sn7 socket that could be swapped.

 

[therremans]

I want to build an amp in the next year and will maybe use those ClarityCaps. I may just stick with those vishays for the DV. They should fit fine and that is the big restriction here.

 

[SHIMACM]

I changed my press on some tubes after I removed the preamp output.

Before, I considered the Mullard 6080 to be the best outlet tube in my system. I have the RCA 6as7g, Chatham 6as7g, TS 5998 and the Mullard 6080.

With the removal of the preamp output, the Mullard 6080's stage narrowed and the separation of instruments decreased, while in relation to the other tubes, the stage and the separation of instruments improved.

Chatham 6as7g and TS 5998 now easily beat the Mullard 6080. Even RCA can now compete on equal terms with Mullard.

Has anyone else felt this difference?

I think that contributes to the argument that the tubes sound different in different amplifiers.

 

[bcowen]

I forgot about those big blue capacitors. It really sounds like the height limitation will restrict us. I thought it would be fun to fit real foils. let me know what else you think of.

Do you think using hifi resistors like z-foils on the shunted pot would make much of a difference? Also there are three resistors coming off of the 6sn7 socket that could be swapped.

Yeah, the Z-foils probably would make a difference, but hoo boy...they are pricey.

I replaced the cathode resistors on the 6SN7 socket with Riken carbon films, and actually listened before I added the (Fitz mod) caps. Noticeable difference. Haven't gotten around to checking the other resistors to see if I have Rikens of the right value....was planning to do that whenever I get around to the volume pot (yes, I'm lazy).

 

[bcowen]

I changed my press on some tubes after I removed the preamp output.

Before, I considered the Mullard 6080 to be the best outlet tube in my system. I have the RCA 6as7g, Chatham 6as7g, TS 5998 and the Mullard 6080.

With the removal of the preamp output, the Mullard 6080's stage narrowed and the separation of instruments decreased, while in relation to the other tubes, the stage and the separation of instruments improved.

Chatham 6as7g and TS 5998 now easily beat the Mullard 6080. Even RCA can now compete on equal terms with Mullard.

Has anyone else felt this difference?

I think that contributes to the argument that the tubes sound different in different amplifiers.

Wow. This is very interesting. When I disconnected the wiring for the preamp outs, I ended up putting them back. I didn't like what it did to the sound....the stage not only narrowed, but got kind of confused sounding. Stuff just didn't 'gel' any more. I didn't say anything because I figured either I was deaf....or everyone else was. But guess what output tube I was using at the time? Yup, a Mullard 6080. I didn't try any other output tube as I wanted to keep comparison variables to a minimum. Thanks for bringing this up....time to give it another go with a different output tube!

 

[JKDJedi]

Yeah, the Z-foils probably would make a difference, but hoo boy...they are pricey.

I replaced the cathode resistors on the 6SN7 socket with Riken carbon films, and actually listened before I added the (Fitz mod) caps. Noticeable difference. Haven't gotten around to checking the other resistors to see if I have Rikens of the right value....was planning to do that whenever I get around to the volume pot (yes, I'm lazy).

The Fitz Mod replaces those resistors..no?

 

[Mr Trev]

ROFL! I was thinking more along the lines of this, but those would work too.

That's the bad thing about octals. That key they use means you can't mount an led in the centre of the socket. My LB amp had a yellowy orange LED installed . I needed to change resistors to dim it a bit, but it looks way cool. So much better than the amps you see with blue LEDs under the tube.

 

[therremans]

The Fitz Mod replaces those resistors..no?

The caps are added in addition to the resistors. Or LEDs are used instead of both resistors and capacitors.

 

[bcowen]

The Fitz Mod replaces those resistors..no?

No. The caps go in parallel with the resistors.