Whats on your amp workbench?

[MikeC]

Cool thanks ! Just wondered if the value had been changef fir some reason. Will replace the blown 2A.

Make sure you use a SLOBLO

[Timoes]

Rodger will do. Cheers.

[Timoes]

So the new slo blo 2 blew within 30 seconds. Amongst the web blurb I did spot a mention of a bad power tube could be the issue. Is this a likely scenario ? I can grab a set of EL34s from the DSL that are known to be running and are fairly fresh and try them.

[MikeC]

So the new slo blo 2 blew within 30 seconds. Amongst the web blurb I did spot a mention of a bad power tube could be the issue. Is this a likely scenario ? I can grab a set of EL34s from the DSL that are known to be running and are fairly fresh and try them.

The amp is clearly drawing too much current. If I was you I'd pull all the tubes, put a new 2-amp sloblo fuse in and see if it blows. I actually have a digital ammeter on my VARIAC so I can see how much mains current is flowing - I'd turn the amp off if the current draw was high. Fuses are expensive!

[RectifiedAmps]

So the new slo blo 2 blew within 30 seconds. Amongst the web blurb I did spot a mention of a bad power tube could be the issue. Is this a likely scenario ? I can grab a set of EL34s from the DSL that are known to be running and are fairly fresh and try them.

The amp is clearly drawing too much current. If I was you I'd pull all the tubes, put a new 2-amp sloblo fuse in and see if it blows. I actually have a digital ammeter on my VARIAC so I can see how much mains current is flowing - I'd turn the amp off if the current draw was high. Fuses are expensive!

^ This is the way.

If you’re doing a few amps and don’t have a variac, a light-bulb limiter is a worth rigging up for cases like this.

[MikeC]

So the new slo blo 2 blew within 30 seconds. Amongst the web blurb I did spot a mention of a bad power tube could be the issue. Is this a likely scenario ? I can grab a set of EL34s from the DSL that are known to be running and are fairly fresh and try them.

The amp is clearly drawing too much current. If I was you I'd pull all the tubes, put a new 2-amp sloblo fuse in and see if it blows. I actually have a digital ammeter on my VARIAC so I can see how much mains current is flowing - I'd turn the amp off if the current draw was high. Fuses are expensive!

^ This is the way.

If you’re doing a few amps and don’t have a variac, a light-bulb limiter is a worth rigging up for cases like this.

I use one for "first time power ups" or "amp status uncertain" power ups. I have a 75W, 100W & 200W incandescent light bulb choices in mine.

[RectifiedAmps]

Lovely little Jansen 6-16 on the bench. Didn’t need much - the non-stock speaker was blown so replaced it with an old alnico that should match well. Also modded the reverb since it went from zero to swimming-pool with the slightest twist of the knob.

IMG_5630.jpeg (3.3 MiB) Viewed 2266 times

IMG_5640.jpeg (4.62 MiB) Viewed 2266 times

[robthemac]

I've been so impressed with every Jansen I've come across. Especially Bruce's.

[jeremyb]

I've been so impressed with every Jansen I've come across. Especially Bruce's.

Do they wipe clean easily after you come across them?

[robthemac]

I've been so impressed with every Jansen I've come across. Especially Bruce's.

Do they wipe clean easily after you come across them?

Tolex is sub-optimal, especially old stuff.

[Jay]

Lovely little Jansen 6-16 on the bench. Didn’t need much - the non-stock speaker was blown so replaced it with an old alnico that should match well. Also modded the reverb since it went from zero to swimming-pool with the slightest twist of the knob.
IMG_5630.jpeg
IMG_5640.jpeg

Nice, interested in the reverb mod you did. If you like, ' ll email you the circuit diagram I did for Strummers' 6/16 based on a bunch of photos he emailed me.

[Bg]

I've been so impressed with every Jansen I've come across. Especially Bruce's.

Do they wipe clean easily after you come across them?

A lot of people think the grilles are beer drains...

[robthemac]

I've been so impressed with every Jansen I've come across. Especially Bruce's.

Do they wipe clean easily after you come across them?

A lot of people think the grilles are beer drains...

Higher viscosity fluids are less of an issue.

[RectifiedAmps]

Lovely little Jansen 6-16 on the bench. Didn’t need much - the non-stock speaker was blown so replaced it with an old alnico that should match well. Also modded the reverb since it went from zero to swimming-pool with the slightest twist of the knob.
IMG_5630.jpeg
IMG_5640.jpeg

Nice, interested in the reverb mod you did. If you like, ' ll email you the circuit diagram I did for Strummers' 6/16 based on a bunch of photos he emailed me.

I just disconnected the cathode bypass cap on the reverb recovery stage. It seemed to even things out a bit but there’s still heaps of reverb available.

I drew up a schematic and took some voltage measurements while I was at it but thanks for the offer! It’s a cool little amp. The tremolo is lush and works over a broad range, which is uncharacteristic of some of the older Jansen designs. It also has a LOT of treble on hand. The presence control is actually just a second treble control, which is very needed to cut the piercing highs.

[Jay]

Transforming a 1960s? radio into a single ended guitar amplifier. ... fun project

Edit - project here: https://www.nzguitars.com/forum/viewtop ... 41&t=43162

20240904_164013.jpg (2.72 MiB) Viewed 1306 times

20240904_193113.jpg (4.51 MiB) Viewed 1306 times