NZGuitars.com : Filling you with GAS since 2003

sizzlingbadger wrote: ↑Tue Apr 05, 2022 6:22 pm I wonder what that little signal diode is in there is for.

Bias rectifier

7027A are like a heavy duty 6L6GC and are likely to be original to the Amp.
You may find that they are still quite serviceable.
A bench test for power output will determine that for sure.

This (your amp): AF image2.jpg Actually, it's not. This is my amp. IMGP0007.JPG Correct, apologies. The other one is one that got serviced by RectifiedAmps. Same thing though, parts going in all directions with bare leads, etc. Always have this mental picture of ladies in the Jansen workshop 'sodde...

RectifiedAmps wrote: ↑Fri Jan 14, 2022 6:27 pm There's also the little-known 6-thirty as well:

tempImagenGtR7t.gif

I have one on my bench right now. Bias was in excess of 50mA so I had to do my bridge rectified bias mod instead of the singe diode.
Managed to get (-)10v more and got the bias spot on for the plate volts at 40mA.

I don't know if Clarry has it. I have it (
from F/B Jansen page) but I can't post it here for some reason. And yes it's 6 valves, 20 watts.

Ask on the Facebook Jansen Amplifiers page. There is a Jansen 6/40 schematic available there which is almost identical.

Did a pre sale service on this Amp: https://www.trademe.co.nz/a/marketplace ... 3WD17uwxAE

MikeC wrote: ↑Thu Aug 05, 2021 4:21 pm Just being pedantic but you'd swear after watching this that current flows from positive to negative. Guess what...

Chinese valves have retrothermionic cathodes which suck up electrons?

6DZ7 ( 2x EL84 in the same bottle) a rare beast! I have some with projects in mind.

Try approaching your local High School Engineering Teacher, Schools have all the metal working gear. They may even be interested in using your project for young music Students.

Livesound.

jimi wrote: ↑Wed Dec 09, 2020 1:42 pm Ampeg SVT or nothing

Marshall VBA400?

Some knowledge here, the designer may even chime in.https://www.facebook.com/groups/255658085128294/

It’s close to finished now, the cabinet is sounding pretty good with the G10 Greenback. I’ll post some clips once I get some time. Having some noise Issues with the EF86 so we are going to swap some tubes until we find a low noise stable one. I suggest that you use metal oxide or film resistors aro...