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Bottlehead Amplifier Discussion / Comparison Thread: Crack, SEX & Mainline - Page 30

post #436 of 1637
Originally Posted by skeptic View Post

It just kills me that mouser won't let you modify your order after a couple of hours, even though they frequently take two days to get it out the door.  Nothing like paying double shipping because you forgot $.50 worth of resisters.

I have been lucky a few times where I will instantly email them with the adjustment i need (same email as the order confirmation), and they would either delay the shipping, or send the extra parts out with free shipping. Doing the live chat if it's available may yield quicker results too. I also spend a good chunk of $$$ with them, so I may get treated differently too...


It sure is a pain in the arse though when you find out too late :angry_face: 


EDIT: Just checked my past 6 months order history and have spent a little shy of $2k, so preferential treatment is a good possibility lol.

Edited by brunk - 2/25/14 at 5:15pm
post #437 of 1637

Welcome to our world. Everyone around here is trained to ask everyone else in the office if they need anything before firing off an order. Otherwise we sometimes see two different orders to the same vendor on the same day. It really sucks when it's for the same part...

post #438 of 1637

In my younger days I hand built small circuit boards for a living, so I am least worried about the soldering aspects of it. It has been a while but I think like most things, it will come back pretty quick.

post #439 of 1637

^^ or when you receive the duplicate items, mail them back and they say it isn't in "retail condition" (no refund) because of a missing screw or torn package when you didn't even breathe on it.


Looking at you Digi-Key :angry_face: 

post #440 of 1637



Originally Posted by mcandmar View Post


Then there is the other extreme where you get basket bloat.  The longer you hold out the larger the basket becomes :rolleyes:


The other day I walked into the local electronics shop because I needed to pick up some XLRs. Maybe $20 worth.





Half an hour and $200 later... :blink:


post #441 of 1637
Thread Starter 

I received my HE-500s today and eagerly compared the Mainline and S.E.X. driving these planars with some fascinating results. Normally I would have described the S.E.X. as slightly brighter or perhaps drier sounding than the Mainline which is very smooth despite great treble extension. Driving the HE-500s though the S.E.X. actually sounds warmer than the Mainline with the Mainline having significantly more sparkle in the higher registers.


I've switched back and forth a few times and although the Mainline is not a particularly high powered / high gain amplifier (I'm using around -13.5dB attenuation) it sounds like it has plenty of oomph for the HE-500s. The S.E.X. has miles of headroom as you'd expect, but the Mainline keeps up in dynamics and power while outclassing the S.E.X. noticeably with its refinement and resolution on the HE-500s. It's interesting to note that I think the performance gap between the Mainline and S.E.X. is probably greater with the HE-500s than with a dynamic can like the T1s.


I wouldn't expect the Mainline to drive something like the HE-6, but can now definitively confirm that it more than holds its own with both LCD-2s and HE-500s having tried it now with both.

post #442 of 1637
Nice mini review with the Hifiman Lachlan. Thank you
post #443 of 1637
Thread Starter 

It was very mini! And you're very welcome!

post #444 of 1637

So I couldn't help myself and gave into temptation.  Trying to improve something in which I find 0 fault is the definition of a fools errand.  I tried to resist, but the lure of a unique and theoretically unparalleled pair of new output caps for my mainline ultimately prevailed over reason and logic, and I went ahead and ordered up a pair of the 10uf 310V custom RTI teflon caps from the very limited stock available through http://tctubes.com/teflon-capacitor.aspx  


As noted and depicted on on the bh forums (in one of the crack cap threads), these are manufactured for use in a serious megabuck preamp, and the specs happen to be perfect to replace the stock film caps in the mainline.  Looks like they hit my mailbox this afternoon.  I'm totally excited notwithstanding the recommended 500 hours of burn in time!    

post #445 of 1637

Mike, your not alone I also succumbed to temptation (I must be mad) so far they have 150hr on the burn-in rig (Grainger method) and about 50hrs in situ. Sounding simply stunning so far. Thanks for the Mainline info its defiantly on the to do list and looks like THE ideal application for them. By the way my uf values match exactly @ 10.34uf


I might just add that my purchase was not specifically for use with the Crack and represents more of longer term investment for future builds to come.



Edited by JamieMcC - 3/18/14 at 3:45am
post #446 of 1637

Wow, this looks very impressive!


I hope you don't mind asking, but what kind of potmeter is that?

post #447 of 1637
Originally Posted by Tom1510 View Post

Wow, this looks very impressive!


I hope you don't mind asking, but what kind of potmeter is that?

It is a Valab 23 step attenuator I found it quiet a nice upgrade from the stock pot considering its relatively inexpensive price.

post #448 of 1637
Thread Starter 
@skeptic, please share your impressions. I can't wait to hear if there's the potential for the Mainline to sound even better!
post #449 of 1637

Thanks for sharing the pics of your installation in the crack Jamie!  I'm thrilled to hear that you're hearing good things out of the RTI's.  What's the total combination of coupling caps you've got in each channel now?


My RTI's did indeed arrive and are now in place in my mainline, singing sweetly!  As depicted, they're a little too large to sit down between the C4S boards and output transformers, where the stock coupling caps previously sat, so I ended up mounting them just above/overhanging the c4s boards.  They are "anchored" via adhesive zip tie mounts stuck to the outer metal edge of the output transformers.  I'll have to keep an eye out to see whether the adhesive really holds over time, but the caps are actually supporting their own weight via fat, rigid leads.  


The sound is supposed to change quite a bit over the next few hundred hours, but my sense is that the mainline, with the RTI's, already sounds a tiny bit more transparent than stock, with slightly increased micro-dynamics and possibly even cleaner transients.  From the limited articles I've read on the subject (e.g. http://www.reliablecapacitors.com/pickcap.htm ) this seems consistent with teflon caps' ultra low dielectric absorption and dissipation factor.  I'm definitely looking forward to seeing how they mature with burn in and will make a point of reporting back on that.  The mainline is so good stock, that I certainly wouldn't suggest this is a necessary upgrade, but these are clearly outstanding, ideally spec'd coupling caps for the mainline, if any of you are so inclined!



post #450 of 1637

Mike, I am pretty excited about how the caps work out in the Mainline for you and will be looking forward to hearing some further impression when you have a few more hours on them. Nice install by the way, with the cap leads straight to the terminals.


Just a thought, I checked with Tyler at TC Tubes prior to installing mine, I do not know how the mainline is laid out but as you read the print on the cap from left to right, this indicates intended directionality. With a output cap location in mind, the output of the cap would be the end on the right hand side when viewed so that you are reading the print. Without turning off my Crack I cant remember which way round it is however one lead is longer than the other and this also corresponds to the direction.


My Crack is currently running 104uf in each channel this is made up of three capacitors two 47uf PIO Valab Fast Power (polypropylene in oil) and one RTI 10uf Teflon. This is working out rather well and been a lot of fun so far experimenting. My plan is to keep the Teflon in place for a while to help with burning in then remove it for a day or two in order give just the Valab caps a try on their own.



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