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β24 monoblocks [[complete]]

beta24

Re: β24 monoblocks on custom stands - in progress

Postby amb » June 12th, 2018, 11:38 pm

Contact me via PM about getting more JFETs.
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Re: β24 monoblocks on custom stands - in progress

Postby Rabbit » July 6th, 2018, 12:20 pm

Progress report:

Got both boards biased up with the new quads. Figured out the in-rush issue with a couple of relay timer circuits and 5 ohm in-rush current limiters. Making progress on the casework. I got 1 of the amps initially put together minus sides, top, and back. This is just an initial mock-up so don't worry about lacking grommets and stuff. The bottom piece is a 5" x 5" x 1/8" thick aluminum square tube. There are 2 large vent holes under the heatsink fins and also 2 holes on the bottom to allow air in. I'll also vent the back and top panels. I have 1/4" plate for the sides and some 1/8" angle pieces for the back and top. I'd love to plexi the back in a later iteration. I may also shorten the power leads from the amp to the relays - the relays were supposed to go inside the PSU enclosure but that did not turn out to be feasible.

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Re: β24 monoblocks on custom stands - in progress

Postby Rabbit » July 27th, 2018, 2:46 pm

I'm making progress on the enclosures. They are turning out exactly how I imagined.

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Re: β24 monoblocks on custom stands - in progress

Postby Rabbit » August 1st, 2018, 1:53 pm

I re-did the top piece and added handles. Are the handles too industrial/suitcase/rad? :lol:

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Last edited by Rabbit on January 7th, 2019, 6:58 pm, edited 1 time in total.

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Re: β24 monoblocks on custom stands - in progress

Postby amb » August 1st, 2018, 4:22 pm

I like it. Very stylish in a unique way!
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Re: β24 monoblocks on custom stands - in progress

Postby Pieterh » August 2nd, 2018, 11:47 pm

Congratulations with finishing your B24's! Wil you move your amp's a lot? You used speaker protection? Which one is it?
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Re: β24 monoblocks on custom stands - in progress

Postby Rabbit » August 4th, 2018, 9:39 am

Pieterh wrote:Congratulations with finishing your B24's! Wil you move your amp's a lot? You used speaker protection? Which one is it?


Thanks! I do move the amps a little bit. The handles are not growing on me, so I think I will remove them. luckily it's just 2 holes that can easily be filled with screw heads.

I'm not using a speaker protection board. The SMPS does have over-current protection, but I don't know if that will be sufficient in the event of amp failure.

My current to-do list:
take the amps back apart, sand the aluminum panels where they are visible.
Add grommets
Add Zobel, input switch, gnd loop breaker, and XLR
Re-assemble
Stands

But, the baby will be here soon...
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Re: β24 monoblocks in progress

Postby Rabbit » January 6th, 2019, 8:10 pm

Happy New Year! My baby came on August 14. She's doing great and we're getting adjusted to the 2 kid lifestyle. I still have to figure out how to be outnumbered by my kids when my wife is not there, but I'm working on it!

I've had my monoblocks in service since my last post, having not addressed any of the to-do items. I'm working on changing that now. I am scrapping plans for custom stands at the moment so have removed that from the title.

Input wiring and gnd loop breaker: the gnd loop breaker was installed between Pin 1 and the gnd lug of the XLR connector.
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Zobel on output terminals
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I've also installed grommets in one chassis. Still to do is a bit of sanding and painting, installing grommets in the other chassis, installing mesh in the large holes to keep tiny fingers out, shortening a couple of power wires, and re-assembling.

The amps sound great. The SMPS physical whine is still there, but due to the amps being behind my speakers, I only hear it when I reach to power them off. Maybe in a couple more years I'll lose those frequencies to tinnitus and only my kids will hear it. :lol:
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Re: β24 monoblocks [[complete]]

Postby Rabbit » January 19th, 2019, 3:01 pm

Grommets, mesh, and painting are now complete. Wires shortened. The amps are all buttoned up. Calling it done for now, which makes me very excited!!

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Re: β24 monoblocks [[complete]]

Postby amb » January 19th, 2019, 5:22 pm

Very cool!
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