1.5 / 2A fuse

[fritzthecat]

I am just curious - I read quite a few times that there are some issues with the 1.5 A fuse BH delivers with the Kaiju Kit. So far I had no problems and am still using the 1.5A one - can someone tell me at which point otf the build the 1.5 was most likely to blow? I am just about to finish my first build now.

[caffeinator]

Hello,

I have just been through that and I think my experience sounds consistent with those of others.

After good readings and no problems on the first HV check, the fuse blew on testing with 300B's right after that, and then blew a second time.  I was able to find some 2A slo-blo fuses, and using those, things checked out fine and no more issues.  I'd have tried 1.5A, but those weren't readily available.

I think after finishing up and some break-in, I will switch back to the correct rating (1.5A fast-blow) and see what happens.  On future builds, I might try using the Variac to ramp up voltage instead.

Best of luck to you!

David

[fritzthecat]

Hi David

thank you for your reply - I then guess my 1.5A fuse just still is alive as I always used the variac with the 300b tubes inserted -anyway tonite or tomorrow I'll find out when finally adjusting the hum balancing etc. I have to turn it on again. My heart is always pounding like crazy when I have to do testing or turn on something I just built - I hope Kaiju number 1 is not gonna blow in the end - so far I had no big problems. Just couldn't find time this week to get some speakers on my workbench and to be honest just was afraid of screwing everything up just in front of the finish line...;o)

Maybe a sip of whisky helps before I push the power button. Three days ago I just did the output transformer wiring - so we'll see...

[ebag4]

Hi Fritz, that is a nice looking build you have there.  My experience aligns with David's, my fuse blew just after adding the 300B's as I recall.  No issue with the 2A slo-blo.

Best,
Ed

[2wo]

That is a very nice build indeed...John

[fritzthecat]

Hi altogether - perfectionism is my biggest pain in the a... and others hate me for that as I tend to expect the same from co-workers...;-)  But actually I just love what I am doing sooooo much and building tube electronics - especially hardwired is just a great hobby and I am already saving money for the next Bottlehead kit - a bee pre with lots of tuning parts - looking very much forward to that one. A great day to everybody and I like very much being in here - it is a great Forum to exchange experience an knowledge. If anyone once makes it to Switzerland you are welcome in my house...:-)

[fritzthecat]

PS: does anyone know where to get choke covers for the ones used within the Kaiju and how to attach them? To me it looks like one would have to türemove the frame holding everything together? Ideally I'd like to get some copper covers like AN uses but as far as I was able to research they have nothing available that fits. Actually I'd like o pimp the optics a little - like within the lomited edition Kaiju and Bee Pre.... In one of my Firstwatt F5 I build an aluminium cage around the toroid transformer to avoid the last bit of hum

[mcandmar]

That is a very tidy build, i applaud your attention to detail

[Paul Birkeland]

PS: does anyone know where to get choke covers for the ones used within the Kaiju and how to attach them? To me it looks like one would have to türemove the frame holding everything together?

Yes, and if you do that, you will most likely ruin the choke in the process.  The covers are installed when the chokes are being manufactured, and then are squeezed and varnished into the channel frame. 

[caffeinator]

There are transformer (and choke) covers that are more like cans or boxes that simply conceal the things underneath.

Search on ebay for "transformer cover" and you'll get many, many results.  One challenge is the footprint around the Kaiju chokes isn't really compatible with the typical covers, which tend to be either circular or rectangular in section (viewed from atop the transformer/cover).  It might be easiest to fabricate a custom cover.

Good luck!

David

[Paul Joppa]

Be aware that the plate choke dissipates a bit more than 2 watts, and a tight enclosure will make it more difficult to dissipate that heat unless some allowance is made for air flow.

[fritzthecat]

Yes, and if you do that, you will most likely ruin the choke in the process.  The covers are installed when the chokes are being manufactured, and then are squeezed and varnished into the channel frame.

This is exactly what I thought - so it's better to forget about that and maybe build a aluminium chassis around the choke allowing some airflow to avoid any heat problems - as far as I know these chockes can get quite warm so it is better o think about "air condition" - already got something in mind I similarly did for my Firstwatt F5 transformers - let's see, I love building everything with my own hands - guess I'll come up with something. Mostly I got more solutions than problems...;o) Anyway, thank you for your reply - very helpful.

Cheers,

Chris

[fritzthecat]

At the moment I am using the 2A fuse but the 1.5 A made it through all test procedures even with inserted tubes when using the variac. When just pushing the power button I decided to insert the 2A type as I am a bit afraid about damages when the fuse blows (though it blows to avoid exactly that). I'll try the 1.5 A type tonite when just turning the amp on - let's see what happens.

I have a question regarding fancy tuning fuses: In my other kits I am using furutech or Hifi-Tuning high end fuses and they really improve the sound. So my question: does anyone have experience using these sound improving fuses in bottlehead kits? I read that they might react different than the standard types - so what does "different" mean in this context - are they not protecting my amp as they should or as the standard fuses do? So far I never experienced any issues but how is it with Bottlehead Kaijus for example?

Input regarding this is very much apreciated...;o)

[fritzthecat]

I'll try the 1.5 A type tonite when just turning the amp on - let's see what happens.

Hi there - just for the sake of it: 1.5A blew immediately when pushing the power on button...