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Bottlehead Amplifier Discussion / Comparison Thread: Crack, SEX & Mainline - Page 31

post #451 of 775

Thank for the reply Jamie - that sounds like a really nice cap combo you're running in your crack!  Wish I could easily jump the pond and arrange to meet up and give her a listen. 

 

The issue of the proper orientation of non-polarized caps has me a bit confused.  I read up a bit on it before putting mine in, and per http://bottlehead.com/smf/index.php?topic=2366.0 and a few other sources I stumbled on, the general advice seems to be that you should connect the "outside foil" lead of a non-polarized coupling cap to the plate of the tube.  I also read that the outside foil lead is often, but not always, the short one (see, e.g: http://www.v-cap.com/installation-notes.php).  I couldn't find anything confirming this holds true for the RTI's - so I just guessed, perhaps incorrectly.  I think I may call Tyler or even RTI directly and see if I can get some confirmation on which lead goes to the inner vs. outer foil.  PJ spells out a way of testing this in the thread linked above, but I'm not sure exactly how one goes about "putting some ac across the cap."

 

For safety, I should really pick up some appropriately sized sleeves for the leads anyways - so I'm not at all opposed to uninstalling and reversing them.  

 

Edit - just spoke with Tyler (really a nice guy), and he confirmed that Jamie has the right of it.  He did test the caps on his scope, and the long lead is the outside foil (opposite of vcaps).  Tyler explained there's no harm in running them backwards, but you can get slightly better noise performance the other way around.  Thanks again for calling this to my attention Jamie!


Edited by skeptic - 3/19/14 at 10:46am
post #452 of 775
Thread Starter 
Wow, skeptic. You've really piqued my interest now. I'm looking forward to any further impressions you'd like to share as they burn in
post #453 of 775

Arg, me too. Just ordered a pair for my mainline. Btw, once I get my custom enclosure completed, I'll upload some pictures. I went with a high gloss black power coated top plate, and a high gloss finish on Amboyna Burl for the case. 

post #454 of 775

Nice ^  Please share some glamour shots with us when she's all put together!

post #455 of 775

I have tried a couple of times now to contact RTI via their contact from but it keeps crashing for me I am wondering f its because I am UK based. I was hoping to quote them the part number for the Teflon Capacitors GHC10625 to see if it was possible to get the spec sheet or some more info about them. Anyone US based care to give it try see if it will work for you?

 

http://www.rtie.com/category-s/65.htm

 

 

 

Just looked in at TC Tubes to get the number they only have 10 left I think there were 40 when I brought mine!

 

 

 

 


Edited by JamieMcC - 3/21/14 at 2:50pm
post #456 of 775

Has anyone tried driving the following 'phones with the Mainline?

 

LCD XC (currently own)

TH900 (contemplating future purchase)

AKG K812 (contemplating future purchase)

ATH W3000ANV (contemplating future purchase)

 

Ideally I would like a great "all-rounder" amp to drive them  all.  Another strong contender is the Auralic Taurus MKII, so if you have heard both amps, I would particularly like your input.

 

Cheers and thanks

 

Nathan

post #457 of 775
Thread Starter 

I will be able to try the TH-900s at an upcoming meet here in Melbourne, Nathan and will be glad to let you know how they pair with the Mainline. They're a great headphone, but I have found mixed results when I've auditioned with some other amplifiers so far...

post #458 of 775
Thanks Lachlan - Greatly appreciated. I'm certain my T1s will sound great with the Mainline!
post #459 of 775

Mike, I don't know how to describe what's going on with my Crack at the moment, only that its really neat! I use my laptop in the evening to catch up on admin, normally listening to music while doing so, but this evening the music coming out has just been just particularly captivating. The play list has been on shuffle and each new track just sounds so fresh and clear (sorry for the lack of a better description). its been so distracting in the end I packed in trying to work and am just enjoying listening now.

post #460 of 775

Received and install a pair of the RTI caps in my Mainline. It's early (only 5-6 hours), but already I consider this an upgrade to the stock 10u Daytons. They need to burn-in for sure, but detail, separation and tonality have all ticked up a notch. The lower frequencies are interesting; initial listening had the bass take a step back in clarity and impact. Right around ~5 hours, they started coming into focus. If I had the funds I'd pick some of these up for my Crack. When the dust settles I think these will prove to have been a very good cap/deal.

post #461 of 775

From my aural bliss yesterday today is the exact opposite really muddy distorted and loose to the point I turned the amp off and checked to see if anything had come loose inside. Fingers crossed it will come good with some further burning in I have had similar experiences while burning in film caps and it never lasted very long before coming back into focus. 

post #462 of 775
Quote:
Originally Posted by JamieMcC View Post
 

From my aural bliss yesterday today is the exact opposite really muddy distorted and loose to the point I turned the amp off and checked to see if anything had come loose inside. Fingers crossed it will come good with some further burning in I have had similar experiences while burning in film caps and it never lasted very long before coming back into focus. 

 

Yep.. I had this happen with my BH Crack (w/ film caps) as well.. it sounded really warm, thick, and distorted for a short while.. I too thought it was a tube or something up with the Crack.. it passed.. and sounded even better on the other side.  I'm pretty sure it's the caps breaking in.

post #463 of 775

Sounds like I'm in for some interesting twists and turns as these RTI's burn in.  Thanks for the impressions and updates guys!

 

I did finally have a chance to reverse my caps, and to cover the exposed leads with heat shrink, and it got me thinking about safety issues and the exposed underbelly of my mainline - which resides on a table top that is now within the reach of my somewhat rebellious 4yo daughter.  I've been keeping it unplugged when I'm not at home but am now eyeing blumenstein's bases and acrylic bottom plates.  (http://www.blumensteinaudio.com/amplifierbases/)  Nice looking, and it seems like this might go a long way towards preventing a terrible accident/shock if the amp were ever pulled off the table.

 

Work has been hectic, and I'm heading out of town tomorrow, but I'm looking forward to more listening and the maturation of the new caps when I get back.   


Edited by skeptic - 3/27/14 at 2:37pm
post #464 of 775
Quote:
Originally Posted by skeptic View Post
 

Sounds like I'm in for some interesting twists and turns as these RTI's burn in.  Thanks for the impressions and updates guys!

 

I did finally have a chance to reverse my caps, and to cover the exposed leads with heat shrink, and it got me thinking about safety issues and the exposed underbelly of my mainline - which resides on a table top that is now within the reach of my somewhat rebellious 4yo daughter.  I've been keeping it unplugged when I'm not at home but am now eyeing blumenstein's bases and acrylic bottom plates.  (http://www.blumensteinaudio.com/amplifierbases/)  Nice looking, and it seems like this might go a long way towards preventing a terrible accident/shock if the amp were ever pulled off the table.

 

Work has been hectic, and I'm heading out of town tomorrow, but I'm looking forward to more listening and the maturation of the new caps when I get back.   


Mike that sounds like a good idea re the base especially with a little one around they are so inquisitive at that age. Only last weekend I had a little accident. I had half of my morning cup of tea go over on bed side table, the Crack is on the table also and was unscathed but my 20 odd year old Marantz speaker amp lives under it and didn't fair so well, it was running at the time and is toast now, it made a quiet a racket as it died even let out a puff of smoke, from the noise I thought the speakers would be shot also but they seem to be ok. It actually served as a bit of a wake up call regarding safety and my own little one who if was her would have most probably got a cloth and tried  to clean up while all was still live.

post #465 of 775

Kids do throw a lot of new angles at you. I remember having to get a gun safe, gates for the stairs, covers for electrical outlets, latches for cabinets, etc. Looking at our customer demographics there are probably a whole lot of you getting near or in the midst of starting a family.

 

At the risk of sounding obvious tube amps get hot, use high voltage and have breakable glass parts. They are definitely not toys for kids, even with a cage on the top and a cover on the bottom. Covers are items that we mention in the manuals as being something the builder should install if they feel it necessary for safety in their particular environment. Just getting them up out of reach of small people can be 90% of the solution. That said, my kids survived in a house full of them that had no covers or cages and sometimes were just breadboards with clipleads. So did a cat and a few different dogs (though we did always keep the goats outside). I think perhaps even more important than covers is educating kids to be safe around these potentially hazardous things much as we do around a stove, a strange dog or a swimming pool.

 

Thankfully I am a recently-become empty nester. Now we can leave dangerous stuff sitting on the dining table, swear profusely, have wild sex on the kitchen counter and yes, leave the covers off our tube amps. Getting old ain't all that bad.

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