Penta "Project Twins"

65 replies

I recently picked up a Beomaster 5500 w/ Master Control and Beogram CD5500, off of Craigslist from a gentleman planning on moving out of town. He was trying to lighten his load before his travels. His family was the original owner of the system and said he was selling it because the speakers were "no good" with the system. On my drive home from picking up the system, I realized I forgot to ask what kind of speakers he was using. Unfortunately, the seller didn't answer his phone so I headed home.

In a later email, I found out that they were hooked to Pentas that were already loaded into his trunk for the move. He said that the amp in one has blown out so he bypassed it and ran the speakers with a Sony receiver. He and his friends named them "The Twins" since they would crank them up and their music could be heard from down the block. I had a feeling this would be quite a project but the seller offered me a good price.

So begins, "Project Twins"

My initial thoughts, before opening the system was that I'd have to fabricate new metal, re-foam, replace the fabric, re-cap, and fix the amplifier fault. If only life were so simple...

Initial pictures:

 

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This project is going to take a bit of time since I really busy working on a new tech startup, but I'll try my best to keep my progress posted.

 

 

 

 

 

Now, check out the fried crossovers (both are fried, one more than the other):

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egoh wrote:
Now, check out the fried crossovers (both are fried, one more than the other):

These Pentas seem to have seen some parties in their time! The crossovers should be easy to sort out though unless the coils have actually melted and have short circuits.

With some luck, the pentagonal metal cap might still be available as a spare part; worth asking a dealer I think.

I'd leave the pushed in dust caps of the woofers last, they won't affect the sound that much. Good luck, this will be interesting to follow!

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(Sorry the automod kept your first post ransom for so long, I think it was due to the number of external links to the pics. During holidays, it may take a little while before any of us mods come around to take a look at the queue.)

Wow those Pentas have been abused. Look forward to the restoration!

Welcome to Beoworld.  Always interested in a speaker refurb project.  And another Yank to boot!

But what's with the Bronze level? No - thumbs down  Come on, gold, man, gold!🤒

If you continue with pics and descriptions like this, for my part you can stay as a bronze member, to look at, you have problems with at least one coil. Compliments for starting a thread like this and over here.

WELCOME

Location: Mexico city

Retired
Printing machine technician
Restored various 1960-70 items
Rock and Roll music
Collecting Vinyl
Restored Jukebox Wurlitzer 1050

tournedos wrote:
unless the coils have actually melted and have short circuits.

Hey guys, I sourced a used top cap and top copper trim from eBay. I'm going to look into fabricating all of the stainless panels. Talked to B&O and found out they are still available but quite costly....so, it should be cheaper and more interesting to fabricate.

Coil L6 (1.8mH) for the woofer and L3 (100uH) on the midrange for both speakers are burnt. I'd like to repair them instead of swapping the entire crossover. I can't seem to locate coils with similar gauge wire (32 AWG) so I might just have to wind them. It's been 20 years since I messed with crossovers so I'm a bit rusty. I'm assuming that a lower resistance coil would mess with the design so it's probably better to stick to the factory 32 gauge. Anyone have a source for air coils with 32 gauge wire?

Also, what is everyone's brand preference for crossover caps?

Thanks!

I can't give a higher recommendation to Mark at

Thanks Rich, I just sent Mark an email. That would simplify things a little.

 

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