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Belton Brick Reverb in small combo.

Started by bandmbill, March 17, 2011, 09:24:46 AM

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bandmbill

Hi All

I have just got a Kustom KGA16R amp on ebay.  It has a short Belton 2 spring reverb that works but doesn't sound too smooth - I was thinking of replacing it with a Belton reverb module - I will need to add a 5V regulator - I was thinking of using the circuit from the Belton PDF spec sheet for this module (without the direct signal path) - anyone done the same or similar?

Bill

J M Fahey

Haven't done it yet but I'm very interested in what you find.
Please post whatever you do, pictures, samples, etc.
Thanks.
PS: it *should* work according to Belton, I trust them, they won't shoot their own foot after becoming "Reverb Kings".

bandmbill

Been working on this one - reasoned that the amp's reverb circuit should have been designed to suit the spring fitted so I should be able to sub the brick in with a minimum extra components.

Put a pair of 47K trimmers in as input and output volume controls - a pair of 100nF caps to block DC - a 7805 with a couple of caps to get 5V to drive the brick.

Didn't have a schematic for the Kustom but had one for a 15W Marshall - worked out that I connect the out from the brick to where the spring was connected - the input for the brick connected back to the middle of the divider feeding pin 3 of the 4558 that drove the spring - had the 7805 powered from a 9V battery at this stage - all works OK.

Needed to find power from the amp - tried to connect to the +17V driving the pre-amps but this pulled the +17V down to +7V  now connected to the +22V supplying the power amp IC and all is fine but the 7805 will need a heatsink.

Sounds good - much better than the spring - will play with setting the in and out levels a bit to get useful travel on the reverb level knob.  Will also need to tidy up the in and power connection.

J M Fahey

Nice *verbal* description.
A schematic or equivalent drawing would be *much* nicer.  ;)


J M Fahey

Ah! you are bypassing not only the tank but the driving section also, good :tu:
I had understood from your verbal description that you had just pulled the tank and hooked the RCA cables straight into the brick  :loco :duh
Congratulations.
Care to post a cost breakdown, plus some pictures?
Thanks.

bandmbill

Picture of how the bits fit.

Cost - the Belton Brick + 1GBP.

bandmbill

Having problems posting an image - keep getting a server error 500 - any ideas?

bandmbill


J M Fahey

*Very* nice, congratulations. :tu: :tu:
Please post the Belton unit cost and where you purchased it.
Thanks.

bandmbill

I think that the Belton Reverb modules came from Small Bear Electronics LLC - around 20USD each.

Cheers

Bill

J M Fahey


morgoth2006

The 7805 will dissipate quite some heat dropping 22v to 5v @100ma. Remember to use a heatsink or you could try a different chip. The Maxim MAX5035 would do.
http://datasheets.maxim-ic.com/en/ds/MAX5035.pdf

bandmbill

I have added a 50mm x 35mm x 1.5mm bit of aluminium as a heatsink - it gets warm quite quickly but has worked for a couple of hours without a problem so far.

Suggestions for an alternative regulator?

morgoth2006

#14
The problem with linear regulators is heat. A switching regulator is a better choice in those cases, like the MAX5035 i suggested.
You could also try this circuit http://www.romanblack.com/smps/smps.htm

Edit: If you want a nice drop in replacement then you can try http://www.dimensionengineering.com/DE-SW050.htm, I have one and its quite nice but 15$ is a bit too much.