Bose 901 re foaming

I started to help out Drew Campbell, owner of Paramount Automation with a set of Bose 901 speakers.

There are 18 four inch woofer that need to be done. Once we started pulling the woofers out we had to make sure we colour coded the leads as there was no rhyme or reason to the colour that Bose used.

Shimming the voice coil had to be done with very fine paper as the gap has a small tolerance. We managed to get through a few woofers but this will be a time consuming project.

Advent/EPI Hybrid

I would like to introduce Henry Kloss to Winslow Burhoe, I hope you two get along fine.

The Advent/EPI hybrid is complete and sounding wonderful, I am letting the music play to burn in the film caps. Right now the sound is much tidier with film caps than electrostatics. The tweeter is more disciplined with a film cap and I hope it opens up more as the electrostatic cap is airier.

I put in the Epicure tweeter originally but aesthetically I like the EPI tweeter more, you judge for yourself. 

I first gutted the internals of the box and marked out my cut outline.

I hacked out a square with a small saw. I know it looks rough but I am a hack.

I recapped the crossover to a single 10.7 uf film cap as per EPI 100's. I left the inductor in place as it probably rolls off around the old crossover point of 4000hz.

 

I reassembled the speakers again and added sealing material to the back of the tweeter to keep the acoustic suspension in place. I do not have a router or a Dremel tool so making the tweeter flush mount was not an option at present.

Next up is to throw it into the line up.

 

Aesthetically, I like the retro look of the EPI tweeter instead so I did a quick swap.

 And now they sit in good company again.

Advent EPI hybrid project

After a few beer listening session to the recently refurbished Advent/2002 I got to thinking I wonder what these speakers would sound like with EPI tweeters.

Luckily for me I have a pair of EPI C70 kicking around, these are a half done project as I have already recapped the crossover, installed cooper lead wires and 5 way binding posts. The woofer was previously replaced and sucks badly.

I opened up the EPI's and disconnected the woofer leads and resealed the speaker. I did the same to the Advent's but disconnected the tweeters and voila Advent bottom end in original cabinets with EPI top end.

In one word WOW!

I have a spare set of Epicure tweeters that would look awesome in the mirror images cabinets of the Advent/2002. I will simplify the crossover to a 1st. order and install Solen 10uf poly caps as per the original EPI 100 speakers.

This is a mock up of what the end product will look like.

 

Surprising enough I believe the parameters of this speaker will be almost the same as what is offered over at Humanspeaker, the Human Model 81

I look forward to this project, in the meantime I have to listen to the concept as a stacked pair.

JBL L60t project

Along with the Advent/2002's I bought was this pair of JBL L60t in need of some serious help. The cabinets are all square and need a little wood filler where someone decided to rip the JBL logo's off.

Woofer surrounds need to be ordered on line from eBay, which I have not done yet.

I was told both tweeters worked fine but when I got home one tweeter was DOA. I opened it up to see that the copper leads from the  terminals to the voice coil had oxidized and turned to aqua blue dust. Apparently this is a common problem for these tweeters at this stage of their life. The glue that they used in production reacts over time with the copper leading to failure.

$80.00 and 1 week later the guys at Vancouver Audio Clinic had this tweeter repaired.

For this project I will re foam the woofers, replace the capacitors with poly film type and change over the resistors to audio grade. I will also install copper wire from the terminal cup to the crossover and then to the drivers.

Sanding and oiling the veneer will not take place until the weather is better outside.

Here is the current state of these L60's.

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Telefunken TLX 11 Professional

My regular scouring Craigslist yielded this pair of utilitarian Telefunken speaker from Germany. The 8" woofer bares the same design as Braun or A/D/S but the tweeter is different.

I had to add a banana plug connecter to the stock wires that come out the back. Once apart it did not seem worth while to install binding posts.

These are nice musical speakers but the 8" woofer lacks deep bass, I would assume it is due to the smaller cabinet size. The highs are very airy and seem to surround me with sound.

One does get a light show from the overload indicators when driven moderately.

Seventies Stereo also had a write up on these speakers.

Advent 2002 speaker

The Advent 2002 was a Henry Kloss design speaker that was built to the Advent/4 specs but by Jensen International. This is the second pair of Advent's that I have owned. The first pair was the Advent/2W with the double tweeter a score from a garage sale.

This pair of Advent 2002 came in a package deal with a pair of JBL L60t's that are in need of a make over, which will be a project that I will blog about later.

I was pleasantly surprised in the great condition these Advent were in overall. The foam surrounds had long rotted away and the Advent badge was missing from the grill.

For this project I opted to not only replace the foam but upgrade to gold plated binding post, poly film capacitors, a new resistor and copper lead wires to the drivers. While I was at it I resealed all around the drivers and back plate.

The old electrolytic capacitor had a value of 5uf and I changed it to 4.4uf and kept the original inductor.

I have had a good thirty hours of run time on them and they are really starting to open up. The bass is nice and tight due to the long throw woofer and the acoustic suspension design. The midrange is laid back and the tweeter is pleasant without being shrill. They are not nearly as bright as the Advent/2W. I am enjoying these speakers immensely.

More information can be found  here at Audiokarma

Hello my name is ______ I am a Speakerholic

Welcome to the Speakerholic blog!

This blog is dedicated to all the cool speakers from the 70's and 80's that get to aurally please me in the man cave.

Most of the speakers I come across are castaways sitting on the shelf of a thrift store or estate sale.

Many times these speakers are in need of repair, refoaming or rebuilding.

I like to refurbish them with upgraded parts and if I like them I keep them. Lots of them I pass along for a very reasonable price for the next speakerholic to enjoy.

Inspiration for this site is from Lloyd Naftolin's site Seventies Stereo and Audiokarma, so enjoy this site.