Bottlehead Amplifier Discussion / Comparison Thread: Crack, SEX & Mainline
Jan 26, 2016 at 5:15 PM Post #1,441 of 2,108
Both the 650's and 800 are just ridiculously good with mainline - you can't go wrong!  If you do ever pick up the latter though, make sure you give sorrodje's hd800 "french mod" a try, as described elsewhere.  It is derivative of what Senn did with the hd800S but costs about $10 and takes 5 minutes to install.  Way better than the old style anax/damping mods.  
 
Congrats again on scoring George's lovely build, and welcome to the summit and the thread! 
 
Jan 26, 2016 at 6:21 PM Post #1,442 of 2,108
I am now the happy owner of George's Mainline. George's work is not only extremely beautiful, but has been a monumental upgrade in sound quality for my HD650.

It actually feels pretty weird to be at the summit, with not much to look forwards to (without spending thousands more). Haha.

Can't wait to try an HD800 on the Mainline too, but I'm pretty certain that I'll be sticking with the HD650.


Hey that's great, congratulations and welcome to the bb. 
 
But be warned trying the hd800 out can be painful on the wallet.
 
Jan 26, 2016 at 6:24 PM Post #1,443 of 2,108
I am now the happy owner of George's Mainline. George's work is not only extremely beautiful, but has been a monumental upgrade in sound quality for my HD650.

It actually feels pretty weird to be at the summit, with not much to look forwards to (without spending thousands more). Haha.

Can't wait to try an HD800 on the Mainline too, but I'm pretty certain that I'll be sticking with the HD650.

 
If you like the HD650s you should give the Nighthawks a go. Better in every way (IMO), but still rich and musical and sublime with the Mainline. So good in fact that I sold my HD800s!
 
Jan 26, 2016 at 8:27 PM Post #1,444 of 2,108
  Both the 650's and 800 are just ridiculously good with mainline - you can't go wrong!  If you do ever pick up the latter though, make sure you give sorrodje's hd800 "french mod" a try, as described elsewhere.  It is derivative of what Senn did with the hd800S but costs about $10 and takes 5 minutes to install.  Way better than the old style anax/damping mods.  
 
Congrats again on scoring George's lovely build, and welcome to the summit and the thread! 

 
 
 
Hey that's great, congratulations and welcome to the bb. 
 
But be warned trying the hd800 out can be painful on the wallet.

 
 
   
If you like the HD650s you should give the Nighthawks a go. Better in every way (IMO), but still rich and musical and sublime with the Mainline. So good in fact that I sold my HD800s!

 
Thanks all! It's very welcoming to be greeted by three of the veterans in this thread... each one of your reviews were carefully read to ensure that the Mainline was a good match for me! 
 
@skeptic Yes, I've been following the mods on that forum to figure out what to do with the HD800 if I were to ever get one!
 
@JamieMcC Yes painful on the wallet, but hey, with the new HD800S out, now is a great time to buy an HD800! Also, since I have the amp figured out, most of the money I would lose playing around with pairings are now saved!
 
@Loquah Thanks for making this thread btw. I will try the Nighthawks sometime and see how they compare!
 
Quick question about the Output Impedance on the Mainline: On the website, it said that low/high gain was 16/64ohm, while the manual states 16/128ohm. Does anyone know for sure? Also, what does everyone think is the best setting for the HD650/800, whose impedances are both 300ohm?
 
Jan 26, 2016 at 9:42 PM Post #1,445 of 2,108
The best impedance is the one that sounds best... but usually, for dynamic drivers, you want a lower output impedance, as long as you can get enough power. The higher impedances will boost the bass around the driver's resonant area, which you may or may not like. The BHC is ~120ohms out IIRC, so you could try the 128 ohm output to check out what that popular pairing might sound more like.
 
Jan 27, 2016 at 12:48 AM Post #1,446 of 2,108
   
 
 
 
 
Thanks all! It's very welcoming to be greeted by three of the veterans in this thread... each one of your reviews were carefully read to ensure that the Mainline was a good match for me! 
 
@skeptic Yes, I've been following the mods on that forum to figure out what to do with the HD800 if I were to ever get one!
 
@JamieMcC Yes painful on the wallet, but hey, with the new HD800S out, now is a great time to buy an HD800! Also, since I have the amp figured out, most of the money I would lose playing around with pairings are now saved!
 
@Loquah Thanks for making this thread btw. I will try the Nighthawks sometime and see how they compare!
 
Quick question about the Output Impedance on the Mainline: On the website, it said that low/high gain was 16/64ohm, while the manual states 16/128ohm. Does anyone know for sure? Also, what does everyone think is the best setting for the HD650/800, whose impedances are both 300ohm?

 
I personally found the high impedance setting preferable with HD800s, but as @jodgey4 says, it's all about personal preference. There's actually a lot of conflicting information about the pros and cons of output impedance and damping factors. Most of it tends to suggest that the lower the impedance (and therefore the higher the damping), the better, but a few scattered articles suggest it's not so cut and dry. I'd share the links if I had them, but I haven't kept them. Suffice to say, the best test is your ears and every headphone will be different. The best thing about the Mainline is you can try both just by flicking a switch!!
 
Feb 15, 2016 at 1:58 PM Post #1,448 of 2,108
Feb 15, 2016 at 2:33 PM Post #1,449 of 2,108
That's a nice selection. Almost makes me want to create a reason to buy them!

 
Postage and import fees to the UK would be significant. I also spotted these which look a like they could make a interesting and cost effective output caps for the Crack add a $15 choke in the power supply and the fifth 50uf could should work fine in place of the last electrolytic in the power supply!  
 
http://www.ebay.co.uk/itm/5PCS-50uF-850V-Vishay-MKP1848-DC-Link-Filtering-Polypropylene-Film-Capacitors-/262044284465?hash=item3d030e7631:g:IrgAAOSwQTVV8qd0
 
Feb 15, 2016 at 3:23 PM Post #1,450 of 2,108
Replacing the last cap or bypassing I thought to be  really is one of the best audible upgrades. The bypass caps, will add colour, depending on what you put in. The M-Caps are fairly transparent and to my ears and don't affect the sound of the crack at all. They do a slightly better job with transients and detail than the factory, but I didn't find memorable change. I'd have to have a pair of Cracks side by side to really hear it. Ultimately I think the M-Caps outperform the power supply by a good margin.
 
Feb 25, 2016 at 3:27 PM Post #1,451 of 2,108
Mainline Tube Rolling
 
I couldn't resist trying the 6S15P in the Mainline and the results have been interesting there is certainly some noticeable differences to the 6S45P-E Gold Pins I have been running for the last 9 months.
 
 
 
 
So a few observations in comparison to the 6S45P-E Gold Pins, bearing in mind I only have been using them for a couple of days now.
 
The general sound of the 6S15P is more crystalline in nature than 6S45P-E which I think sounds the more organic or analogue of the two. You could say the 6S15P has a touch of solid state about it compared to the 6S45P-E .
 
The 6S15P without doubt delivers a higher level or resolution its revealing lots of new little details and I have found myself several times now lifting my cans off my head to check/listen for sounds in the house which they were actually new details revealed on the headphones.  
 
Treble comes across as crisper and cleaner with more headroom it is a slightly more etched treble. Listening to a orchestral piece recorded in a large cathedral the music feels like it’s soaring up into the high vaults of the cathedral ceiling and the shimmer on cymbals impressed.
 
Mids feel a fraction less intimate and involving emotionally compared to the 6S45P-E however this is a area where the sense of presence and density of tone has continued to improve with run time.
 
Bass seems tauter with a fraction more punch and a noticeable increase in its texturing.
 
Depending on what genres your preferences are it’s got to be good to be able to roll tubes and still tweak the Mainline just a little to suit personal tastes.
 
The 6S45P is my favourite for folk/bluegrass or small ensemble acoustic music and feel it does a better job of delivering textual clues with a more natural and life like tone of solo instruments and vocals.  While the 6S15P digs up increased level of details of the wetness and hollowness of a note blown through a woodwind instrument the 6S45P is a fraction less resolving but to my mind delivers the more convincing tone of the note and woody-ness texture of the instrument through which it was made.
 
The 6S15P comes into its own with more complex music and orchestral where its separation and air help with the portrayal of scale and crescendo while the higher resolution helps with digging out some nice little instrumental nuances from amongst the orchestra.  Before I turned in for the night I wanted to check out a couple of tracks on Florence and the Machine's Ceremonials album which is a reasonably busy album and ended up  listing to the whole thing finally turning in at 2am…
 
Cheers
Jamie
 
Feb 25, 2016 at 8:05 PM Post #1,452 of 2,108
  Mainline Tube Rolling
 
I couldn't resist trying the 6S15P in the Mainline and the results have been interesting there is certainly some noticeable differences to the 6S45P-E Gold Pins I have been running for the last 9 months.
 
 
 
 
So a few observations in comparison to the 6S45P-E Gold Pins, bearing in mind I only have been using them for a couple of days now.
 
The general sound of the 6S15P is more crystalline in nature than 6S45P-E which I think sounds the more organic or analogue of the two. You could say the 6S15P has a touch of solid state about it compared to the 6S45P-E .
 
The 6S15P without doubt delivers a higher level or resolution its revealing lots of new little details and I have found myself several times now lifting my cans off my head to check/listen for sounds in the house which they were actually new details revealed on the headphones.  
 
Treble comes across as crisper and cleaner with more headroom it is a slightly more etched treble. Listening to a orchestral piece recorded in a large cathedral the music feels like it’s soaring up into the high vaults of the cathedral ceiling and the shimmer on cymbals impressed.
 
Mids feel a fraction less intimate and involving emotionally compared to the 6S45P-E however this is a area where the sense of presence and density of tone has continued to improve with run time.
 
Bass seems tauter with a fraction more punch and a noticeable increase in its texturing.
 
Depending on what genres your preferences are it’s got to be good to be able to roll tubes and still tweak the Mainline just a little to suit personal tastes.
 
The 6S45P is my favourite for folk/bluegrass or small ensemble acoustic music and feel it does a better job of delivering textual clues with a more natural and life like tone of solo instruments and vocals.  While the 6S15P digs up increased level of details of the wetness and hollowness of a note blown through a woodwind instrument the 6S45P is a fraction less resolving but to my mind delivers the more convincing tone of the note and woody-ness texture of the instrument through which it was made.
 
The 6S15P comes into its own with more complex music and orchestral where its separation and air help with the portrayal of scale and crescendo while the higher resolution helps with digging out some nice little instrumental nuances from amongst the orchestra.  Before I turned in for the night I wanted to check out a couple of tracks on Florence and the Machine's Ceremonials album which is a reasonably busy album and ended up  listing to the whole thing finally turning in at 2am…
 
Cheers
Jamie

 
Thanks so much for sharing this, Jamie! Just when I thought I was done with tube rolling...
 
So, is the 6S15P a straight swap? Any modifications required?
 

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