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Crack;Bottlehead OTL - Page 94

post #1396 of 4719
Quote:
Originally Posted by Cryok95 View Post


Wow so I guess you are using 100uf Obbligato PSU caps? Are they worth the price compared to the axon/solen 100uf caps?

 

I can't personally comment on the axon/solen 100uf caps.  I did my initial upgrade from the stock caps in the Spring of '11, after parts connexion had already sold out of their 100uf stock.  So I bought the 91uf version instead.  To my ears, the obbligatos are definitely worth the ~$50 premium over my old axons.  The sonic differences between these caps is about on the same order of magnitude as rolling various well made 12bh7's.  

 

If you check out the cap comparison at www.humblehomemadehifi.com/cap.html , the author describes the axons as good budget caps, having a slight "focus in the lower treble range" and lacking in air and micro detailing.  I haven't compared very many different caps, and wouldn't try to describe the differences to this level of detail by ear even if I had.  But with the obbligatos, I am finding the trebles to be just a tad less prominent and more natural sounding (closer to live instruments) and that deep bass is improved in quality and quantity.  (Again, I assume the change in bass stems mostly from the 9uF increase in capacitance, as several of the threads on bh discuss how deep bass rolls off as you decrease the capacitance of your output caps.)  These were welcome changes from my perspective, particularly given that I spend the bulk of my listening time with hd800's (that do not require any added "focus" in the lower trebles).

 

For example, in addition to my ordinary array of well recorded test tracks (e.g. k2hd jazz at the pawnshop and we get requests, simon&garfunkel - live in nyc, mfsl gold ella and louis again, chanticleer - evening prayer, songs for distingue lovers, etc.), I decided to throw on some 2pac (all eyez on me), to see if I was really hearing things right down low.  Lemme just say, the bass was hitting hard, in a good way - a way I did not expect to hear from flagship open Senns.  Needless to say, I'm really enjoying my crack these days!         

post #1397 of 4719

I am wondering if someone could answer a couple of voltage testing stage questions for me?

 

How are you guys securing your rigs for the voltage checks? I can't find a stable way to do this? If I need to have in both of the tubes which are quite high, I can't rest it on the wood base (Which I haven't yet assembled) and I don't have a vice or anything.

 

 I don't understand the instructions 5 and 6 on page 38. If I use the negative probe clip to connect to terminal 12, how can I connect the same lead to the ground buss?

post #1398 of 4719
Quote:
Originally Posted by networkn View Post

 

How are you guys securing your rigs for the voltage checks? I can't find a stable way to do this? If I need to have in both of the tubes which are quite high, I can't rest it on the wood base (Which I haven't yet assembled) and I don't have a vice or anything.

 

I put two thick flat markers on both sides between the top plate and the wood base closer to the transformer. That way the tubes didn't touch the table and I had access to the power switch. Or, you can put something under the wood base on both sides, like books. Be careful with the voltage checks. Remember to have your shoes on and put one hand in the pocket. And don't lean over live circuit! To be on the safe side I put on rubber gloves when I perform voltage checks.

 

 

Quote:
Originally Posted by networkn View Post

I am wondering if someone could answer a couple of voltage testing stage questions for me?

 

I don't understand the instructions 5 and 6 on page 38. If I use the negative probe clip to connect to terminal 12, how can I connect the same lead to the ground buss?

 

Terminal 12 is connected to the ground.

post #1399 of 4719
Quote:
Originally Posted by networkn View Post

I am wondering if someone could answer a couple of voltage testing stage questions for me?

 

How are you guys securing your rigs for the voltage checks? I can't find a stable way to do this? If I need to have in both of the tubes which are quite high, I can't rest it on the wood base (Which I haven't yet assembled) and I don't have a vice or anything.

 

I just used some plastic boxes lying around and put one under each corner of the face plate. Just make sure all the boxes are roughly the same height and all of them taller than the tallest tube you have on it. (But then I work in a bio/chem lab so I have more plastic pipette tip boxes than I care to admit biggrin.gif)

post #1400 of 4719

I flipped the chassis over and let it rest on the wood base in a perpendicular direction, such that the power transformer and the 6080 tube is inside the base, and the 12AU7 is outside. Resting the chassis flush to the right gives you easy access to the power switch, which you will when checking the headphone out voltage during power-up/down.

post #1401 of 4719

That custom crack in gold is stunning ;_:

post #1402 of 4719

Got my crack, realised the speedball boards were on backorder...

 

Which is not a problem, except i just forwarded my crack amp from US to SG.

So forwarding charges will apply again...

post #1403 of 4719

Just finished my amp. Sounds sweeeet. Will post pics soon!

post #1404 of 4719

I just got a UPS shipping notice from my order on Dec 13, I guess I know what I'm doing this weekend!

post #1405 of 4719

Listening to the crack with an rare amperex bugleboy 12au7. This tube is something special. Rolling around with other 12au7s also, but i prefer the amperex so far.

RCA Cleartops are actually not too bad either. I have a mazda 12au7 coming also, does anyone here know how the mazda sounds?

 

Will try a rca 12bh7a once my speedball boards arrive.

 

TUBE ROLLING FTW.

post #1406 of 4719
Quote:
Originally Posted by Cryok95 View Post

TUBE ROLLING FTW.

 

Meh. I've tried to enjoy tube rolling but I get REALLY bored REALLY fast. I'd much rather just sit and listen than try and analyse any possible differences.

post #1407 of 4719

Just ordered mine, hope shipping it to the UK doesn't take too long. 

post #1408 of 4719

I see, HD600/HD650 + Crack is wonderfull combination. Anyone has tried HD700 + Crack combination yet? Will it fit same good too?

post #1409 of 4719

Crack + HD700 = Heroin for me...it's that good.
 

post #1410 of 4719

Hi fellas, I need some advice about refining my formula ingridientsbiggrin.gif

 

I have an oppurtunity to  replace the output caps with 630v/10uF paper-in-oil Ampohms. They're 65mm in diameter and 95mm in length. Questions:

 

1. Any info on the quality of the quality of these caps?

2. I don't have any experience at dealing with installing such big caps, Do you think these would be hard to fit in the case?

3. What would be the best value to compensate the output resistors for 600ohm 'phones? Would it have an eefect on the output impedance?

 

I have the SB installed btw.


Edited by Amarphael - 1/26/13 at 11:31am
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