new dumble build in bassman head chassis

[andresound]

Hi guys,
Here goes.
I have decided to attempt a Dumble build in a Bassman 50 head chassis. From what you guys have said, the iron was used by Mr Dumble himself. So that is one part sorted. Hererwith are pics of the donor chassis.
[IMG768]http://i48.photobucket.com/albums/f214/ ... hojrog.jpg[/img]
Out of cab. Sorry about bad pics.
[IMG:768:1024]http://i48.photobucket.com/albums/f214/ ... kq6isi.jpg[/img]
[IMG768]http://i48.photobucket.com/albums/f214/ ... bzuapi.jpg[/img]
[IMG768]http://i48.photobucket.com/albums/f214/ ... nufreq.jpg[/img]
Codes on iron Mains PT (a bit blured and upside down)
[IMG768]http://i48.photobucket.com/albums/f214/ ... rhuyr6.jpg[/img]
OT
[IMG768]http://i48.photobucket.com/albums/f214/ ... lgh0t5.jpg[/img]
Choke
[IMG768]http://i48.photobucket.com/albums/f214/ ... 57lbxo.jpg[/img]
Back of chassis number
[IMG768]http://i48.photobucket.com/albums/f214/ ... i74o4r.jpg[/img]

May somebody can help with dating. Looks to be 69?
I will strip and start to clean tomorrow and post.

ANY input, coments and advice would be greatly appreciated.

[Chris G]

Looks like it has some mods already... ...The year, looks like a 68 bassman to me ...I don't think it's a Bassman 50...

[andresound]

Has to be a 50w bassman! 2 x 6L6!! I believe it was "black faced"!

[Long Distance Call]

Actually, all the Bassman heads have 2 x 6L6's (or 5881's). If it's a Bassman 50, it should have 50 watts printed under the output jacks. If it doesn't have it, it' most likely a 40 watt amp.

Your amp has both 1968 and 1969 transformers and if I remember correctly, the Bassman 50 didn't come out until around 1972.

Also, it's interesting that your amp has "Bassman Export-Amp" on the faceplate, something I've never seen here in the U.S.

Based on the pictures, it looks to me like much more was done to the amp besides just "Black- Facing" it.

In my opinion, you have the best vintage iron for a 2 x 6L6 Dumble style amp and it's going to sound great!

Good luck with the project,
LDC

[andresound]

Thanks for that info LDC.
The export logo was a multi-tapped PT (110-240v) version.
Looking forward to the build. Awaiting a quote on BOM from rj, then I will get started. Really looking forward to it!!
Will probably gut the amp first.

[Long Distance Call]

Yes, every "Export Model" made by Fender for the overseas market has a multi-tapped power transformer. But, every "Export Model" I've ever owned (or even seen) has a standard Bassman-Amp faceplate, just like the domestic amps. Your amp has a "Bassman Export-Amp" faceplate and that's what I find so intriguing...

Cheers,
LDC

[RJ Guitars]

Andre, that looks like a cool start... I'll be interested in following along and see where you end up. rj

[andresound]

Found this on page 3 of Dumble Files. What do you guys think about this layout? Done in a bassman chassis!
[IMG768]http://i48.photobucket.com/albums/f214/ ... kfrypy.jpg[/img]
Built in dumblelator?

[brentm]

Found this on page 3 of Dumble Files. What do you guys think about this layout? Done in a bassman chassis!
[IMG768]http://i48.photobucket.com/albums/f214/ ... kfrypy.jpg[/img]
Built in dumblelator?

You should have room since the electrolytic caps for the power supply will be underneath the chassis in the dog pan of the bassman.

[andresound]

Well, its confirmed, the amp is a 69!! PRIMO IRON!!!
I am told that the eyelet board in the above layout is the same as the bassman's. I will strip, clean and check boards for conductance and report back.

This build might be a bit "above my pay grade", but hey, how else am I going to learn!! .
I have to reiterate, the help I am getting from members and the time they have invested, is truly inspiring.

THANK YOU!!

[andresound]

Good source for period correct SPRAUGE caps???

[andresound]

Took out the main board. Cleaned boards and checked for conductance.
[IMG768]http://i48.photobucket.com/albums/f214/ ... da367l.jpg[/img]
[IMG:768:1024]http://i48.photobucket.com/albums/f214/ ... nl1gvz.jpg[/img]
[IMG768]http://i48.photobucket.com/albums/f214/ ... dw4spp.jpg[/img]
[IMG768]http://i48.photobucket.com/albums/f214/ ... jd9ivj.jpg[/img]

Next will be the Power supply board and then the chassis. Does anyone have the colour codes for the 69 bassman iron leadouts for choke, PT and OT?

[jelle]

Testing for conductance is not done I that way. This will lead to false negative results.

It is done in circuit. yeah.

Put B+ on one eyelet. Ground a couple of eyelets that are nearby. Then measure for leakage with the probe set to mV.

Try some free eyelets in the vicinity of the B+ one, and also the side of the board as well.

[martin manning]

I don't see value in keeping the old board. Its warped condition suggests it has absorbed moisture at some point.

[andresound]

Thank you for that. Live and learn. The more I hang around here, the more stupid I feel!! No worries, all good.
I agree with Martin, no use in keeping old boards.