Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: Jimb0 on February 25, 2021, 05:54:38 AM
-
https://www.parts-express.com/Audyn-Cap-Q4-100uF-400V-MKP-Foil-Capacitor-027-125
Has anyone used these before and were you able to fit them in the Crack?
Also is it possible to use Audyn 64uf caps to replace the 100uf caps or is this value too low?
Thanks in advance
-
Hi.
I used the Panasonic’s EZP film caps they fit nicely down one side and the t you can get a choke on th3 other side. Take a look at this site, apparently the should fit but you’ll have to use both sides of the panel.
https://www.headphonesty.com/2019/04/upgrading-bottlehead-crack-headphone-amplifier/
It’s full of lots of sensible info. I used the setup pictured on there
Good luck
Martin
-
Thank you for that info Martin and was really helpful in getting the measurements of these caps. I do not think the 100uf Audyns will fit because the EVO Oil Mundorf's that I used barely fit and those were 50mm in width. The Audyns are 60mm so if I were to get them they'd have to be installed outside.
-
To test whether they'd fit, you could cut a 60mm diameter cardboard circle. Then turn the Crack upside down (with suitable supports to keep the chassis in the wood enclosure), and see if the circle can be inserted without hitting the wood side or a heatsink.
cheers, Derek
-
I used Mundorf M-Cap ... 100uf, 250V. It's 66mm L x 56 mm Diameter. That Audyn cap is slightly smaller so yeah, it should fit assuming you havent added anything along the sides.
-
Hi.
I used the Panasonic’s EZP film caps they fit nicely down one side and the t you can get a choke on th3 other side. Take a look at this site, apparently the should fit but you’ll have to use both sides of the panel.
https://www.headphonesty.com/2019/04/upgrading-bottlehead-crack-headphone-amplifier
These are a good idea. Being able to just stick them down to the top plate is very helpful, and they are physically relatively compact.
-
https://www.onlinecomponents.com/en/hellermann-tyton/15127202-12701816.html?ref=searchads360feed&utm_term=151-27202&gclid=Cj0KCQiAst2BBhDJARIsAGo2ldVItnEQpFECOcrwpqtEKqXhbqRiVX7VB7xiCRuJBYq7SknGPnBsEa8aAg7HEALw_wcB&gclsrc=aw.ds (https://www.onlinecomponents.com/en/hellermann-tyton/15127202-12701816.html?ref=searchads360feed&utm_term=151-27202&gclid=Cj0KCQiAst2BBhDJARIsAGo2ldVItnEQpFECOcrwpqtEKqXhbqRiVX7VB7xiCRuJBYq7SknGPnBsEa8aAg7HEALw_wcB&gclsrc=aw.ds)
These are perfect for mounting large capacitors, attach them to the chassis plate with a screw, then a zip tie to hold the capacitor.
-
I drilled my top plate and screwed down the zip tie mounts, 2 per cap. No way was I trusting the double sided tape to hold those big caps over time. I used small, button head, square drive bolts. Hated to drill the top plate but it really doesn't look bad and much better than dealing with falling caps.
If I had known of and used those Panasonic caps, I probably would have used RTV to "glue" them down. Usually holds pretty well and can be removed. There is plenty of contact area with those Panasonic caps that it would probably hold up fine. But that heavy duty 3m double sided tape might hold up long term with those Panasonics too.
-
Mcandmar ... those look great. Wish I knew about them when I built my Crack.
-
If I had known of and used those Panasonic caps, I probably would have used RTV to "glue" them down. Usually holds pretty well and can be removed. There is plenty of contact area with those Panasonic caps that it would probably hold up fine. But that heavy duty 3m double sided tape might hold up long term with those Panasonics too.
The double sided tape to use is called “servo tape†it’s sold in model shops in the U.K. it is used to hold control servos and radio receives in model aircraft and it is STRONG. It’s not your normal double sided tape with a bit of thin foam in the middle or the normal DIY picture hanging stuff. I’ve had no probs with it so far and used it on a few projects over the years. Surfaces have to be clean of course.
Well not quite true, it’s an absolute sod to get of ;)
Martin
-
Not in the UK but I wonder if that's anything like the clear 3M VHB tape?
-
Not in the UK but I wonder if that's anything like the clear 3M VHB tape?
Not sure it’s tape about 1 or 2mm thick and very sticky. Best bet to have a look in one of the model plane or car shops
Not sure if this is what I use cause I buy mine from local model shop but it looks the same. Sure there will be similar on US flea bay
https://www.ebay.co.uk/itm/202948030460?
-
I never rely on tape alone. I used 3M VHB at my last job and it worked quite well But it was not exposed to heat. I recently installed pana EZP caps in my C2A using VHB and after a week one cap came undone. So I installed a 2.25 inch Aluminum standoff in the holes that BH has drilled in the chassis plate, then re taped the caps and butted them against the standoffs and screwed on a fender washer with a nylon shim under it to apply tension on the cap so it can't move. The bottom line is that in my opinion the combination of heat, gravity and weight are all very problematic for double stick tape. Please use a mechanical solution and never worry about it again.
Of course YMMV.
-
I’m a survivor of a faulty tape situation. One of the big caps I used dropped down and the lead made contact with the Speedball heat sink, releasing smoke. Nothing was destroyed, thankfully.
My next life lesson was not accurately lining up the holes I drilled to correctly mount the caps with the view from the top in mind. One is lower down the top plate than the other which aesthetically sucks.
-
I’m a survivor of a faulty tape situation. One of the big caps I used dropped down and the lead made contact with the Speedball heat sink, releasing smoke. Nothing was destroyed, thankfully.
My next life lesson was not accurately lining up the holes I drilled to correctly mount the caps with the view from the top in mind. One is lower down the top plate than the other which aesthetically sucks.
I drilled 4 holes in line on both sides to mount the cap holders. They are kinda sorta straight and even :-)
-
I used the insulated standoffs, they're not cheap but work great.
-
Bottlehead offered a prebuilt Crack years ago where they used 100uF Audyn Q4 caps (1st photo). As you can see, they are really big... so they will take some creative mounting, as Bottlehead did on the wood base.
I personally use the Audyn Q4 68uF caps and they fit just fine (2nd photo).
Here's a chart from years ago (3rd photo) that shows the effects of lowering the output caps' capacitance depending on what impedance headphones you use. For myself, with the 68uF caps, the bass roll-off on my 600 Ohm AKG K240 Sextett will start at 4 Hz (which they can't even play down to)--and 200 Ohm headphones will roll off bass at around 12 Hz. Considering Bottlehead doesn't recommend using the Crack with lower than 200 or 300 Ohm headphones because of the damping factor, 68uF output caps make a lot of sense from what I understand.
-
Hi,
If you read the article on using the tape it does suggest you make a wooden support to go inside under the caps (I’ve not found it’s needed)
I did this installation because I didn’t want to spoil the top plate with bits of cable tie or the old screw head, bolt where it’s obviously not suppose to be .
Just call me OCD lol
Martin