Crack;Bottlehead OTL
Jun 7, 2021 at 4:56 PM Post #11,041 of 12,335
I did a quick listening test for the focal elegia and it works fine. The off volume is at 6 o'clock. anything pass 9 o'clock is too loud for my taste with this headphone. It does seems to have a little more punch than my 650. I also test with the 80hm dt770, that also works fine. It seems like the treble is toned down a bit for the dt770 with this amp, which is a good thing for me =).

I tested this via Ares II Dac.
Sounds good with the Elegia 👍
 
Jun 9, 2021 at 10:59 PM Post #11,043 of 12,335
Are there any Bottlehead designs or variants, including the Crack, that use the 12AT7 tube?
 
Jun 10, 2021 at 2:03 AM Post #11,044 of 12,335
How about using using 6SN7 tubes in a BHC ?
It seems we can also use 6922 tubes but may need an adapter of sort.
 
Jun 10, 2021 at 2:16 AM Post #11,045 of 12,335
How about using using 6SN7 tubes in a BHC ?
It seems we can also use 6922 tubes but may need an adapter of sort.

6SN7 tubes are very common, with a 12au7 adapter. Make sure you have speedball installed, and make sure not to use it in the 6080 socket.
 
Jun 10, 2021 at 2:57 AM Post #11,046 of 12,335
6SN7 tubes are very common, with a 12au7 adapter. Make sure you have speedball installed, and make sure not to use it in the 6080 socket.
Speedball is mandatory for 6SN7 ?
 
Jun 10, 2021 at 6:50 AM Post #11,047 of 12,335
I see quite a few people have custom metal panel with larger size, I wonder where do you guys order those?

There's very little Cracks with a bigger top chassis. Look into the Crack A Two A; as it was designed with a bigger top plate. To allow room for more fancy (big) output capacitors.

Are there any Bottlehead designs or variants, including the Crack, that use the 12AT7 tube?

The Bottlehead Stereomour amplifier uses 12AT7 tubes as drivers for the 2A3 power tubes with great succes. Half of the 12AT7 is used as a shunt regulator for optimal performance of the halve that is driving the 2A3.

How about using using 6SN7 tubes in a BHC ?
It seems we can also use 6922 tubes but may need an adapter of sort.

One could use the 6SN7 without the Speedball. As the 6SN7 is very close to a 12AU7 electrically.
The 6922 is very different. I'd not recommend using it in the stock Crack or with a Speedball without further modifications. One would need to modify the wiring on the socket and R1 on the Speedball allowing more current like 6-8mA for better performance / match to the Crack. Then you'd still have to deal with the greater output / gain from the 6922. A Crack that's modified to use 12BH7 could also use 6922 with an adapter.
 
Jun 13, 2021 at 6:06 PM Post #11,048 of 12,335
Any one heard of this brand of cap? A local shop has these for 5 dollars each.
75 UF 600 V 5% C G Electronics MKP Metalized Polypropylene Capacitor

DBD8D413-1162-4C73-9311-4E54D2450B5C.jpeg
 
Jun 14, 2021 at 9:56 AM Post #11,049 of 12,335
Any one heard of this brand of cap? A local shop has these for 5 dollars each.
75 UF 600 V 5% C G Electronics MKP Metalized Polypropylene Capacitor

That's too big (size wise)
 
Jun 22, 2021 at 12:23 PM Post #11,050 of 12,335
Does anyone have any experience buying a built, pre-owned Bottlehead Crack? Do these things survive the journey, or do the connections come apart during travel?
 
Jun 22, 2021 at 12:43 PM Post #11,051 of 12,335
Does anyone have any experience buying a built, pre-owned Bottlehead Crack? Do these things survive the journey, or do the connections come apart during travel?
I have that experience. I bought a built-to-order BHC+speedball from HeadAmp Builder (James C, Los Angeles CA). The build was gorgeous and the packing was meticulous! Everything was intact and worked perfectly: I live in southwestern Pennsylvania. [FYI, my initial contact with HeadAmp Builder was through Etsy.]
 
Jun 22, 2021 at 12:54 PM Post #11,052 of 12,335
I have that experience. I bought a built-to-order BHC+speedball from HeadAmp Builder (James C, Los Angeles CA). The build was gorgeous and the packing was meticulous! Everything was intact and worked perfectly: I live in southwestern Pennsylvania. [FYI, my initial contact with HeadAmp Builder was through Etsy.]

I had the same experience intra-EU with a very, very nice packing job from a fellow Head-Fier.

I will say that indeed it does require that meticulous packing effort. I think I read above (a few months back) of someone who bought a used BHC and it arrived slightly damaged due to shipping. So I would arrange carefully with the seller about shipping arrangements.
 
Jun 22, 2021 at 2:25 PM Post #11,053 of 12,335
Does anyone have any experience buying a built, pre-owned Bottlehead Crack? Do these things survive the journey, or do the connections come apart during travel?
I bought a prebuilt crack on eBay not too long ago and when it came the plate was bent and the wood base fall aparts. The seller use to small of a box and USPS seems like they dropkick the box.
My friend bought a prebuilt S.E.X which is larger and it came in perfect condition via UPS.
 
Jun 22, 2021 at 2:37 PM Post #11,055 of 12,335
Does anyone have any experience buying a built, pre-owned Bottlehead Crack? Do these things survive the journey, or do the connections come apart during travel?

So I’ve received and shipped multiple Bottlehead amps. Most have been fine. I did receive one unit that was in rough shape: the frame had broken, wires had come loose, screws had fallen out... The sender had made a pretty big mistake by sending it with the faceplate upside down, so the entire thing rested on the internal components.

So Bottlehead has some good instructions on shipping. You wrap the amp with bubble tape first horizontally then vertically. Fill a box with packing peanuts and rest the amp upside down so it’s laying on the top plate with the inside facing up. Obviously there are no tubes in it!

I think there should be good instructions on the website to share with a seller.

Finally, if you’ve never built a kit be wary of buying. If something goes wrong you won’t know what to do. My first kit was purchased instead of built, so I spun my wheels for ages on something as simple as a blown fuse.

The recent kit I bought that arrived mangled I was able to repair successfully! Build one first if you are able!
 

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