Crack;Bottlehead OTL

[Smeggy]

So it looks like there will be a crack at the Seattle meet raffle in October so I'll have the chance to hear/win one.

[guzziguy]

Just arrange a visit to Bottlehead and you can hear everything. You live very close to them.

[ironbut]

The guys are in the beginnings of moving into a larger commercial location. This will include a dedicated listening room and Doc has plans to hold some amp building classes there and will have an open house once the dust settles. That's probably going to happen in Oct.. There's even a gin, vodka etc. distillery in the same complex (with a tasting room!).

IIRC, it's on Bainbridge Island.

[Nebby]

Complete tube noob, so pardon the questions....Any recommendations on where to buy alternate tubes to try? Ebay? Any way to tell if a tube is good/bad without a tube tester or is it just plug in and pray?

[HiGHFLYiN9]

Sure, eBay is a great place to track down tubes. It's usually good to look for a seller who has actually measured the tubes on a Hickok or something similar and has posted numbers and minimums. You can also go to places like Tube Depot if you'd like a company to stand behind what they are selling you, I like the more adventurous ebay buying experience though

I just finished up my Crack, you can see it in the gallery here: http://www.bottlehead.com/smf/index.php/topic,977.0.html

[Smeggy]

That thing is the shit!

Nice job, especially the bottlehead badge. Very nice touch.

[Nebby]

I wouldn't mind a GB for the badge

Thanks for the info, I just didn't know if there was anything specific I should look for while browsing Ebay. Very nice build btw, I think I'm going to stain mine dark like you did and perhaps get the top powder coated black.

[ironbut]

Hey Nebby,

If you're new to the wonderful world of tubes, I highly recommend starting out by buying old tubes from a reputable seller and avoiding the eBay bargains till you get a little experience under your belt (even seasoned tube guys get stuck with junk from auction sites from time to time).

TubeDepot is good as well as TubeWorld and Upscale Audio. You pay more but they all stand behind what they sell (and all the test equipment in the world can't predict some premature failures or noises that don't happen for a hundred hours or so).

I like TubeWorld since they have well tested used tubes that I can try and not pay an arm and a leg for . Once I find the tubes that really do it for me, then I can look for some new old stock and pay the big bucks for them. Also, you don't have to worry about long burn in times with used tubes (although it is a good idea to warm them up without a signal for a couple of hours and give them a few hours with music before you get super critical).

[crappyjones123]

that badge is swanky. nice work.

[ironbut]

Swanky?

Man, I haven't heard that term in a looong time!

Any of you guys remember the cologne company called Swank? They used to have all kinds of funky nic-nacks and a friend of mines dad had a collection of them. He gave me a tiny TV that was actually a cigarette lighter but if you put a 35mm slide and a couple of batteries in it, you could see the slide image on a 3" sq screen. I took a picture of Walter Cronkite and kept that slide in it. I kinda gave up on it since it ate batteries like mad.

That is a killer build !

[Nebby]

Kit arrived today, very well packed kit though it looks like the top panel has a bit of snipe on one edge possibly from the sanding process. The panel itself looked like it was manhandled as well, plenty of dark fingerprint smudges and a couple of decent scratches. Shouldn't be too big a deal though, as I plan on powdercoating the panel. Other than that everything else in the kit looks pristine. Time to break out the soldering iron

[Augsburger]

Please let us know how long it takes you to build/solder, seems like a just patient evening would do it.

[crappyjones123]

i put the whole thing together yesterday (everything besides the speedball). spent maybe 5 hours going over everything 3 times. got everything to work the first time around.

sounds pretty nice. bass is just a wee bit lacking but i think a cap change might help in that dept. nice mids.

questions now - amp gets very noisy past the half way mark on the volume knob. im not experiencing the "black backgrounds" that most others seem to be experiencing. buy different tubes? resolder stuff? reroute wires? suggestions would help.

[crappyjones123]

gaaah nevermind the noise...its the age old problem - my source. just tried my old pcdp. absolutely no noise that i can hear with the central air running in my office. slight grain with the volume turned up all the way but i might be imagining things. guess i have to find me a dac to build.

a side note - the top plate of the amp is REAL hot. have to move my fingers after ~4 seconds. is that too hot or regular for a tube amp?

2 thumbs up with my pcdp. now i know what you were talking about steve (iron) i cant imagine it replacing a zana but for 300 bucks im pretty damn happy. 200 bucks actually since the speedball kit isnt installed yet.

*off to find a dac to build*

[Nebby]

Build a Gamma2

[crappyjones123]

already reading the build log ><

i was curious so i went back to my old t43 and plugged in the amp into that laptop. funnily enough less noise out of the soundcard in that laptop than my 3 month old t410...

[ironbut]

Hey crappy,

You should let the components and tubes burn in for a while. Or you might want to wait till the Speedball's installed. Even 24 hours will help in every category.

Some tubes will quiet down after some burn in.

Regarding the heat on the top plate, be sure and stick those feet that are included in the kit under the case. Without any airflow the plate does get pretty hot around the vents. That's where the plate resistors for the 6080 are and they get hot. I've run my Crack amp (with and without the Speedball) 24/7 for days and days with no problems (although it does get very warm).

[crappyjones123]

so i screwed up the 2 x 2N2222A transistors while trying to put together the speedball kit. instructions said to leave some gap between the board and the transistor. mine are touching the board. should i just get new ones or is it ok for them to touch the board?

also, installed sprague 470uf 200v electrolytic caps for output caps. bass is nicer. but overall tone has gotten bloomier.

[Nebby]

I think they tell you to leave some gap so there's more surface area for it to be cooled by air. Shouldn't break anything but might reduce the lifespan, perhaps?

[ironbut]

I think Nebby's right. It would be a good idea to post something over on the Bottlehead forum (Crack forum) just to be sure.

If you didn't cut the leads too short, you and always try and slip the tip of a toothpick under the transistor as you wet the solder one lead at a time. Just be careful not to "cook" the semiconductor.

The Speedball does a lot to deepen and tighten the bass. I'm not sure which headphones you're using (impedance?) but there's a dandy table on the Bottlehead Crack forum for finding the right size output cap for a given impedance.

Crack

[crappyjones123]

unfortunately the leads are all gone. i will end up just buying 2 more (anyone have an extra pair lying around? will pay for parts and shipping obviously. shipping with digikey is more expensive than the parts themselves...). i am more scared of having done damage to the board as i am sure that will be a much more expensive replacement if required.

here are some pics. upskirt ones later when i turn off the amp but as of right now the toones are playing so dont want to turn it off sounds mighty nice.[ATTACH=CONFIG]3572[/ATTACH][ATTACH=CONFIG]3569[/ATTACH][ATTACH=CONFIG]3566[/ATTACH][ATTACH=CONFIG]3573[/ATTACH][ATTACH=CONFIG]3567[/ATTACH][ATTACH=CONFIG]3574[/ATTACH][ATTACH=CONFIG]3568[/ATTACH][ATTACH=CONFIG]3565[/ATTACH]

[digger945]

Very nice. What kinda part is it you need cj?

[luvdunhill]

Very nice. What kinda part is it you need cj?

Looks like a quad two. Bog standard NPN BJT transistor...

[crappyjones123]

I dont know what luvdunhill just said but its a 2N2222A transistor...quad 2 or something or the other. need 2 of them thingys

[digger945]

Looks like a quad two. Bog standard NPN BJT transistor...

Huh. Pretty sure I don't have those. How bout a 2SC2705? Pretty close on power and hFE