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Author Topic: A review with some construction and modding notes  (Read 2532 times)

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Offline btrancho

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A review with some construction and modding notes
« on: April 01, 2014, 03:56:10 PM »
Construction

Very straightforward.  Just carefully follow the well done assembly instructions. 

A few suggestions-

–   pay careful attention to the wires that connect the baffles to the cups.  Be very gentle. (My 8323s came with the wire pinched between one of the screw posts and the baffle during factory assembly, crushing the insulation a bit and exposing some wire.  They worked fine anyway so I left it alone)

–   Burnishing the metal damping is very important, just as is admonished in the instructions.  I found that a ¼” dowel, cut down to about 4” and rounded over a little with sandpaper to be the ideal tool for most of the work.  A chop stick would work as well.  For the tight spaces I used large finishing nail (not the pointy end!)


–   Removing the backing from the wool felt is a royal PITA.  Rolling it back and forth a little helped with getting the backing away, but I often had to use an Exacto knife and curse a lot.  Eventually, my fingernail enhanced wife bailed me out.

The six foot cable was easy to assemble.  The Mogami cable Doc has chosen is supple and very easy to work with.


Performance

I initially listened to the stock 8323s for about an hour to try to get a baseline and then connected them to an old DAP and let them run for about 36 hours wrapped towels and placed in a box..  Just before surgery I listened again.  The bass seemed to have improved and the mids had improved a lot.  The treble was somewhat rolled off and grainy.

My Crack is fairly stock, with just the Speedball upgrade, a 23 step attenuator, Mullard CV4003 and RCA 6AS7G.

Once modded, these headphones definitely perform well above their price point.  Doc’s mod’s have resulted in a nice, punchy but controlled bass and good mids.  As Doc has mentioned, the transients are very good and “punchy” is a good overall description.. The treble continues to even out over time. These are much more “fun” cans than my HD600s and will suffice quite nicely for those times when closed headphones are called for.  The HD600s are much more refined and neutral.  They will remain my go to cans for the Crack, but these are definite keepers.  They’ll hang right next to my HD600s and I can see myself going to them whenever I want a little more energy and fun in my listening or when circumstance demand a closed can.

I live in a Brooklyn apartment.  Though my neighbors are great and very quiet, come the time of year when the windows are open and city noises intrude, or when the AC is running (most all of July and August), these will be very helpful. 

Mods I’ve made already:

I am not a fan of either TechFlex or adhesive shrink wrap but I originally built the cable to the assembly specs.  I soon found the cable too stiff for my taste, and combined with the stiff heat shrink on the earpiece connector, it rubbed at my shoulder during listening.  I’ve removed the TechFlex and installed another 3.5mm plug.  This is, of course, mostly a matter of individual taste.  For me, the cable is now more flexible and quiet.

The ear pads included are very soft and pretty comfortable but are nowhere near circumaural (unless you have ears the size of dried apricots).  Perhaps I have big lobes, but I found the pads slightly uncomfortable after a longer listening sessions.  I replaced them with a pair of Shure 840 pads.  The Shure fit somewhat loosely so I cut a set of adapters from 2 ply (@ 1.5 mm) mat board that I fit in the grove between the baffle and the cup along with a narrow gasket made from shelf lining material.  This allows the Shures to fit nice and snug and stretches them out to full size.  The added benefit is definitely a better, more solid bass and much better isolation.  For around $15 I strongly recommend these pads.  I'll take photos and post them along with a drawing of the adapter tomorrow.

I didn’t use the supplied foam piece for the headband.  Instead, I sent away to the Tempur-Pedic folks for a free sample of their memory foam (just go to their website to request it) and got a 3”x4” sample about 1” thick.  I cut a 95mm x 10mm piece and used it instead. It’s white/cream color so if looks matter you may want to skip this.  The memory foam is extremely comfortable in this application.
Bob Trancho

Offline Kris

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Re: A review with some construction and modding notes
« Reply #1 on: April 01, 2014, 04:19:28 PM »
Awesome review Bob. Many thanks.
Can't wait for pics and drawing.

Offline btrancho

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Re: A review with some construction and modding notes
« Reply #2 on: April 02, 2014, 02:16:05 AM »
Some photos and the adapter drawing:

The Crackheadphones with the Shure 840 pads.  The pads wrap around the back of the cups.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.trancho.net%2Fimages%2FCrackhead_1.jpg&hash=4d05f7f909c2bb9438681f9b4637b973)

The Shures along side the kit pads
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.trancho.net%2Fimages%2FCrackhead_2.jpg&hash=d76ddc9b11c9f211da15dee94febfd20)

The mat board adapter from the rear.  I used some scrap black mat board.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.trancho.net%2Fimages%2FCrackhead_3.jpg&hash=8be12d8e18709be85922f442cc57f326)

A closeup of the gasket/mat board combo
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.trancho.net%2Fimages%2FCrackhead_4.jpg&hash=98deeed2dd9f06b4add63038c843ad6b)

The memory foam
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.trancho.net%2Fimages%2FCrackhead_5.jpg&hash=e34694e78f3f6d158440532b13a35675)

A drawing I made in working up the adapter.  Note that this may not print out to scale so you might need to adjust if using it as a template.  The only really crucial dimension is the interior cutout.  It has to be at least 63x83 mm but not much bigger.  The outer dimension can be a mm +/- without much functional difference.
http://www.trancho.net/images/BH_Shure004.pdf
« Last Edit: April 02, 2014, 02:19:39 AM by btrancho »
Bob Trancho

Offline JamieMcC

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Re: A review with some construction and modding notes
« Reply #3 on: April 02, 2014, 02:32:32 AM »
Nice write up, its great to see some reviews being posted.
Shoot for the moon if you miss you will still be amongst the stars!

Offline Kris

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Re: A review with some construction and modding notes
« Reply #4 on: April 02, 2014, 08:01:42 AM »
Thanks again Bob for sharing your thoughts and modifications.

Offline Grainger49

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Re: A review with some construction and modding notes
« Reply #5 on: April 02, 2014, 09:34:10 AM »
This is a top notch write up.  The modifications are for personal preference and don't detract from the original product.

Good Job!

Offline Jim R.

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Re: A review with some construction and modding notes
« Reply #6 on: April 03, 2014, 03:37:14 AM »
Hi Bob,

Nice write-up! I'm no fan of techflex or heatshrink myself -- much prefer cotton braid and cotton twine to whip the ends with. My ears do seem to fit the cups as they are, but I might try stuffing the backs a bit to get a wider soundstage -- all depends when I take a closer look.

Thanks,

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 Doc B.

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Re: A review with some construction and modding notes
« Reply #7 on: April 03, 2014, 04:56:15 AM »
Someone should extend the concept of adding the bigger pads by creating a spacer for them that has extra "lift" at the back to angle the drivers like HD800s do. Those nice pivoting yokes that the cups hang in could accomodate that extra angle pretty well. Could be a fairly challenging design project to have made by a 3D printer. Material choice might be a little tricky as it would need to be rigid enough to force the cans into the angle, but compliant enough to snap into the groove for the pad this is molded into the edge of the cup. Or maybe they could be designed to attach some other way, like double sided tape.

I did figure that the pads we provide - which are not any bigger than stock but a lot more comfortable - could be small for some users. That is a common complaint of the Sony cans they are designed for. I find them just big enough. This is one of those cases where we had to choose an upgrade that was easily adapted because it would have been prohibitive to have a small custom run of adapters for bigger pads made. Unfortunately even some pre made parts for other headphones that might be adapted are a little too pricey in small quantities. I bought an HD650 headband pad to try. Finding one was challenging, it was about $18 and after all that would not quite fit. I figured that at that point it makes more sense for the end user to buy a fancy snap on lambskin pad instead of us trying to supply something we have to mark up unreasonably, so we supply the soft foam. Same logic as with our other kits, all the performance is there but if you want to put more expensive stuff into it to make it your own you certainly can.
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.

Offline mcandmar

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Re: A review with some construction and modding notes
« Reply #8 on: April 03, 2014, 05:51:42 AM »
The stock pads lasted about 10 minutes for me, they just felt sticky and unpleasant, i have no such complaints with the replacements provided but then i am used to on ear headphones like the Grados. To me over ears like the Sennheisers feel like i'm wearing a big pair of fluffy ear muffs that get hot a sweaty.

I also had issues with the cable outer covering due to the noise it generates, anytime the cable rubbed against anything hard like the arm rests of my chair it transferred that noise into my ear.  The cable itself has a nice soft silicon rubber kind of feel to it and has no such issues with noise.

I have yet to open them up and do any of the internal mods, so far i have only got as far as replacing the pads and cable. I have to say, even 100% stock out of the box these cans surprised me, i've bought big name headphones for 3-4 times the price of these monoprices that aren't as nice as these, cant wait to see what the internal damping does to them..
M.McCandless