I'm about to order some fuses and I would like to know if 6.3mm x 32mm (presumably the same as 1-1/4" x 1/4") is the correct size for an early 80s JCM800 Mk2 Master Model 100W Lead.
These ones seem to be good quality (250V):
SIBA GZ series (70-059-61/1A): Slow blow (T), 1A
SIBA GZ series (70-059-61 2A): Slow blow (T), 2A
Is it ok (or even better) to use ceramic fuses? I need fuses for other amps and they are only available in this material.
Edit: These fuses fit perfectly. I used a SIBA 70-059-60/1A (Fast 1A) for HT.
Fuse size for early 80s JCM 800
Moderators: pompeiisneaks, Colossal
Fuse size for early 80s JCM 800
Last edited by shattered on Thu Sep 17, 2026 6:34 pm, edited 1 time in total.
-
Stevem
- Posts: 5604
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Fuse size for early 80s JCM 800
I don’t believe that the 1 amp fuse for the HT ( B+ ) should be a slow blow.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Fuse size for early 80s JCM 800
Thanks, I'll stick to F for HT fuse.
Although the amp came with a F1A fuse in HT (not sure if it has been replaced), both the manual and the rear panel indicate T1A.
Although the amp came with a F1A fuse in HT (not sure if it has been replaced), both the manual and the rear panel indicate T1A.
Re: Fuse size for early 80s JCM 800
https://el34world.com/charts/Schematics ... er_amp.png
I'm unclear whether those SIBA GZ fuses are made to IEC60127 or UL248, the datasheet doesn't really clarify.
I'm unclear whether those SIBA GZ fuses are made to IEC60127 or UL248, the datasheet doesn't really clarify.
https://www.justgiving.com/page/5-in-5-for-charlie This is my step son and his family. He is running 5 marathons in 5 days to support the research into STXBP1, the genetic condition my grandson Charlie has. Please consider supporting him!
Re: Fuse size for early 80s JCM 800
From the technical documentation (page 4):
Standards
The following important international and national standards apply:
70-059-61/1A
EN 60 12
IEC 60 257
CEE 4
DIN VDE 0820, Part 1
DIN VDE 0820, Part 2
DIN VDE 0820, Teil 3
UL 248-14
UL 512
CSA Standard C 22.2 No. 248.14
So no IEC60127 / UL 248 compliance... Will look into this when purchasing fuses, thank you. There are more alternatives in 5x20mm size.
Standards
The following important international and national standards apply:
70-059-61/1A
EN 60 12
IEC 60 257
CEE 4
DIN VDE 0820, Part 1
DIN VDE 0820, Part 2
DIN VDE 0820, Teil 3
UL 248-14
UL 512
CSA Standard C 22.2 No. 248.14
So no IEC60127 / UL 248 compliance... Will look into this when purchasing fuses, thank you. There are more alternatives in 5x20mm size.