Bottlehead Amplifier Discussion / Comparison Thread: Crack, SEX & Mainline
Jun 16, 2016 at 2:41 AM Post #1,546 of 2,108
6S15Ps turned up today. Looking forward to getting them out...

 
Interesting results so far with the 6S15Ps. I haven't done any bias adjustments, but so far my order of preference is pretty clearly as follows:
 
  • Electro Harmonix gold pin 6C45P
  • Russian 6S15P
  • Sovtek 6C45P (as supplied with the Mainline kit)
 
More listening still required, but I'm shocked to hear again how good the Electro Harmonix are in comparison
 
Jun 20, 2016 at 2:57 PM Post #1,547 of 2,108
  Really? They say beauty is in the eye of the beholder. Just spray it gloss black and be done! :) Your listening to it, not looking at it.  Then again, I think mine turned out okay.

Show us a picture and we might be able to suggest some solutions

Not exactly butt ugly, but still the paint job could have been better. The wooden blocks are also unpainted.
 
Jun 20, 2016 at 3:34 PM Post #1,548 of 2,108
   
Interesting results so far with the 6S15Ps. I haven't done any bias adjustments, but so far my order of preference is pretty clearly as follows:
 
  • Electro Harmonix gold pin 6C45P
  • Russian 6S15P
  • Sovtek 6C45P (as supplied with the Mainline kit)
 
More listening still required, but I'm shocked to hear again how good the Electro Harmonix are in comparison

 
Your 123 preference is the same as mine
regular_smile .gif
  Which is kind of interesting because the 6c45p I have with gold pins are not Electro Harmonix branded.
 
Jun 20, 2016 at 4:00 PM Post #1,549 of 2,108
Its pretty pointless to try and evaluate different tubes without correctly biasing them, especially with these tubes as the variance can be huge between them.
 
Jun 20, 2016 at 4:04 PM Post #1,550 of 2,108
  Not exactly butt ugly, but still the paint job could have been better. The wooden blocks are also unpainted.

 
Looks ok to me but if you wanted to respray the top I think it would be doable with some careful masking up.
 
Yours has the RTI Teflon signal caps I think doesn’t it? If so did you know they are more normally found in $25000 Audio Research amps!
It seems that due to a mix up in ordering a small batch of around 40 capacitors were made to the right UF value but wrong physical size these were disposed by a third of party substantially below their original cost. Quiet a few I think were snapped up by Bottlehead builders. They went pretty quickly if I remember correctly.
 
http://www.inner-magazines.com/news/209/57/Audio-Research-Anniversary-Edition-Reference-Preamplifier/
 
Jun 20, 2016 at 4:14 PM Post #1,551 of 2,108
  Its pretty pointless to try and evaluate different tubes without correctly biasing them, especially with these tubes as the variance can be huge between them.

I think the bias difference between the gold pin 6c45P and the Russian 6S15P when I did mine was around 10-14 volts from memory. I have noticed my Mainline's bias point does tend to creep a bit so it gets a check every couple of months now.
 
Jun 20, 2016 at 4:23 PM Post #1,552 of 2,108
   
Looks ok to me but if you wanted to respray the top I think it would be doable with some careful masking up.
 
Yours has the RTI Teflon signal caps I think doesn’t it? If so did you know they are more normally found in $25000 Audio Research amps!
It seems that due to a mix up in ordering a small batch of around 40 capacitors were made to the right UF value but wrong physical size these were disposed by a third of party substantially below their original cost. Quiet a few I think were snapped up by Bottlehead builders. They went pretty quickly if I remember correctly.
 
http://www.inner-magazines.com/news/209/57/Audio-Research-Anniversary-Edition-Reference-Preamplifier/


How do I tell if it has the RTI Teflon signal caps? It would be pretty cool if it does!
 
I mean looks is one thing, but sound wise it's absolutely superb, especially combined with the Mojo (even with the iDSD too).
 
Jun 20, 2016 at 5:15 PM Post #1,554 of 2,108
   
The RTI Teflons look like these.
 

 

 
I'm guessing not, do you mean the big white cylindrical things on the left and right?
 

 
Jun 20, 2016 at 6:46 PM Post #1,556 of 2,108
Not exactly butt ugly, but still the paint job could have been better. The wooden blocks are also unpainted.


I'd have a think about treating the wooden base first to see if it helps. It's much easier than repainting the top and might balance the white top a little.
 
Jun 20, 2016 at 6:57 PM Post #1,557 of 2,108
+1 for considering a refinish on the base.
 
I've considered doing a make-over on my SEX amp, which has several flaws due to my meager skills and general impatience...but then I start listening again and stop caring about how it looks :wink:
 
Jun 22, 2016 at 12:12 AM Post #1,558 of 2,108
I'd have a think about treating the wooden base first to see if it helps. It's much easier than repainting the top and might balance the white top a little.

I agree, anyone specializes in this? I want a nice gloss wooden finish or better yet piano black :D
 
  +1 for considering a refinish on the base.
 
I've considered doing a make-over on my SEX amp, which has several flaws due to my meager skills and general impatience...but then I start listening again and stop caring about how it looks :wink:

Lol, yes every time I start listening to my Mainline, it doesn't matter how it looks anymore. This may be my end-game amp! Maybe at least until I can afford a DNA Stratus.
 
 
Yes.
 
I remembered seeing a Mainline with a white top advertised recently with them in thought it was the same one as in your pic but perhaps not. Must have been a different one

Must have been a different one. How much different do these RTI Teflon signal cap's make?
 
Jun 22, 2016 at 2:17 AM Post #1,559 of 2,108
  I agree, anyone specializes in this? I want a nice gloss wooden finish or better yet piano black :D
 

 
While it can be tricky to get the perfect finish, it's not hard to paint the base. I've done a few paint jobs now and so long as you can get a space that's relatively dust free and be patient in between coats, achieving a good finish is pretty straight forward with spray paint tins from a local store. Just buy a primer, some sand-paper and some gloss black paint and then chat to someone at the paint shop for some tips or watch a YouTube video or two.
 

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