Advice needed on faulty Crack Amp

julius · 2377

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Offline julius

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on: December 16, 2012, 03:13:13 PM
Howdy, not too long ago I posted a thread in regards to my bottlehead crack amp going bad.  I've tried to have some experts look at it with no success.  I need some advice.

Will the S.E.X upgrade be a wise choice if there is a potential problem with the circuitry in my amp as it is now?  I mean, if I were to purchase this kit and then send the amp off to someone willing to repair it all for me, can this be done?  Will Bottlehead fix the amp for me and install the SEX upgrades ?

I own the Hifiman Orthos and I really would love to use them with the Bottlehead.  I was wondering, will I need to purchase new tubes for this upgrade, or can I stick with my 5998?  Any help is appreciated guys, I've been trying to find someone to repair my bottlehead crack for the past 2 months.  My crack was purchased as a gift for me, used on another audio forum.  The person who built it did not do a proper job and it was considered potentially dangerous.  It ended up damaging my expensive headphones.  Since then, I've tried to find someone to repair it all for me with no success.  Again though, I would love the ability to use the amp with orthos, as my primary headphones are all Orthodynamics now.



Offline Doc B.

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Reply #1 on: December 16, 2012, 04:47:30 PM
"Experts" who couldn't fix it? Cripes, I hear about that on a regular basis. It's just not that complex a circuit, and if some "Expert" can't fix it, well, maybe he is an expert in something else (like, maybe, claiming he's an expert). Why don't you just contact us and work with us to get it running? We can probably fix it promptly and you can be happy - 206-451-4275, M-F 10-6 PT.

Lesson: if a guy tells you he is an expert, ask him if he created the thing he is an expert about.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline Paul Birkeland

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Reply #2 on: December 16, 2012, 05:34:58 PM
Hello Julius,

Though the hosted image is gone, I do remember your particular Crack clearly.

This is a lot more than just replacing a component or looking for a missed solder joint, the amp needs to be put back the way it was supposed to be built.  This is a little more than your average tech would want to deal with, as they have probably never seen a properly built Crack, and may spend a lot of time figuring out how things were supposed to be arranged from the get go.

We'd be happy to repair it for you, feel free to send it in.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Jim R.

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Reply #3 on: December 17, 2012, 03:37:50 AM
Hi Julius,

You really should get this amp packed up and shipped off to Bottlehead.  If the build is as potentially dangerous as PB originally indicated, it may be you instead of a pair of headphones that gets "damaged" next.

Also, the s.e.x. kit is not an upgrade for the Crack, but an entirely separate product.

As far as the appropriateness of the Crack with Orthos, it is not an ideal choice as it is designed for high impedance headphones and has fairly low output power.  Orthos are typically low impedance and require a bit more power than typical headphones.  If it will work, the 5998 is probably the most likely tube to make that happen as it lowers the output impedance somewhat.

In general the s.e.x. amp will be a better match for orthos (yet will still do a fine job with high impedance cans as well) and it has much great power that most orthos need.

Honestly, right now your best bet is to ship it back to Bottlehead and let them fix it so that it is properly and safely constructed and then you can evaluate how well it works with your existing headphones.

-- Jim

Jim Rebman -- recovering audiophile

Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).

s.e.x. 2.1 under construction.  Want list: Stereomour II

All ICs homemade (speaker and power next)


Offline julius

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Reply #4 on: December 17, 2012, 03:55:17 AM
Thank you all for the quick responses.  I will give that number a call sometime soon.  The Hifiman HE400 is extremely efficient now and runs immensely well off an iPod alone.  I will likely be using the amp with this headphone.  I read this thread recently.  http://www.bottlehead.com/smf/index.php/topic,2520.0.html

If some found the SEX to do well with the HE500, then it would be an excellent match for the HE400 that requires no amplification at all.  My Cowon J3 portable player gives it a ton of low end, push and separation qualities.  So, I had hoped I could get this kit over whatever I have now.  Im not sure what that would entail or cost, but I'll give that number a ring and see what can be done.

-J



Offline Natural Sound

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Reply #5 on: December 17, 2012, 06:09:06 AM
Julius,

Where are you located? There may be a bottlehead that can sort it out for you. I'm in Albuquerque, NM if that helps.

Tom



Offline Jim R.

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Reply #6 on: December 17, 2012, 09:11:13 AM
Tom,

I think he said in his other thread that he is in Ohio. ?

I had no idea you were so relatively close -- I'm in Boulder, CO.  I said relatively :-).

-- Jim

Jim Rebman -- recovering audiophile

Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).

s.e.x. 2.1 under construction.  Want list: Stereomour II

All ICs homemade (speaker and power next)


Offline julius

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Reply #7 on: December 17, 2012, 10:19:03 AM
I am in Ohio, as mentioned above.  Cleveland, actually.  44130...go Bro...go Indi...never mind all of our sports teams are awful.  Go Lake Effect Snow! :[