Bottlehead Kits > Mainline
6C45P tube Rolling
Lambert:
I have been running Mainline with HD800 for a month. It is an awesome amplifier. I upgraded the components last week, e.g. replacing the 10uF capacitor by Auricap 18uF as per Loquah. It was a positive upgrade, the overall signature of the amplifier was kept with enhancement in smoothness in both mid and high tones.
I read the thread about tube rolling. Unfortunately, the gold pin Electro-harmonix 6C45Pi is out of stock from all the shops, e.g. Cryoset and Woo. I am thinking the possibilities to replace 6C45P by Western Electric 417A which are still available in China. I saw some people upgrade their WA7 by replacing 6C45Pi by WE417A with a tube adaptor. Is it possible to use? The electrical parameter of 417A is close to 6C45 but still have some difference. I am a bit of worrying about tube oscillation in Mainline with 417A.
I also find WE437A though it is a bit expensive tube. It is a compatible tube of 6C45P. But it's seemed to me its pins is not 100% the same as 6C45P. WE437A uses a B9D socket while 6C45 uses B9A. Can I still put WE437A into the socket of Mainline or I need to find another tube adaptor?
- Lambert
Doc B.:
The 437A is much closer to the 6C45pi electrically than the 417A. But it needs a completely different socket. The 417A would be a step backwards sonically.
Lambert:
Hi Doc,
Thanks for your suggestion. WE437A is an expensive alternatives ($300+ each) and I don't know how much upgrade it can achieve over 6C45P sonically. People said it was a dream tube but I do hesitate about it.
The stock tube of Mainline is quite good indeed. Maybe I should keep on looking for the EH version.
-Lambert
Doc B.:
IME the difference between the 6C45pi and the WE437A is down to a matter of taste. So I agree that it's a little difficult to justify the price unless one wants an ultimate statement kind of amp. I have not sought out the low noise graded 6C45pis to say if they are any better. 6C45pis are pretty consistently quiet.
dubiousmike:
Hi Lambert - FYI, it looks like Woo will have more of the EH 6c45pi's come month end if you have your heart set on trying a pair. (Scroll down on this page: http://wooaudio.com/products/wa7fireflies.html ) I keep flirting with the idea of picking up a pair, but time flies and I don't ever seem inclined to pull the trigger. I consider it a testament to just how great the mainline is. I keep concluding that my $100 would be better devoted to a bh dac etc. if there is a second run.
Regarding alternate tubes, I thought you all might find this comment by Doug at ECP pretty interesting. By way of background, Doug/ECP's L-2 is a derivative of the parafeed design that Doc and crew pioneered many years ago. Over on changstar (http://www.changstar.com/index.php/topic,1601.40.html), Doug shared the following about his experiments with tube selection in parafeed headamps:
--- Quote ---When I was working on the L-2, I built versions using the 6C45, 5842, 6688, 7788, D3a, C3g, E280F, 12HG7/12GN7, 6J9, and one or two others I can't remember ... 7KY6 maybe? Anyhow, I liked the 6C45 the best. To be fair, I used all NOS tubes there, but I have used the Sovteks and can't say I found them to be any different.
None of the others were bad by any means (except that 7KY6), but side by side in the same circuit, the 6C45 had the best performance to my ear. Even accepting the lower gain and output power, I did not find the 5842 to be as good. Perhaps it is a different story into a higher load.
Pete Millett has an interesting writeup on a bunch of these tubes: http://www.pmillett.com/pentodes.htm
--- End quote ---
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