Sounds

Musical, audio interest

18
Jun
2019

Speaker repair

I have an old NAD-320 amp and pair of JBL Control 1G speakers attached to the TV, but hadn’t used them in a while. Trying out Netflix and finding Hans Zimmer Live in Prague, the TV speakers were certainly inadequate. But what an awful crackling sound from the JBLs. They were about 20 years old, but hadn’t had too much use. Taking off the grill, and the reason was clear…

The foam, around the main cone had gone crispy, cracked and started falling apart. Even 20 years on it is still possible to buy JBL Control 1 speakers new, but I didn’t want to dump these if they could be repaired.

There are a number of repair videos on youtube (search for “jbl control 1 foam repair kit”) and I found a kit on eBay (though the seller doesn’t appear to be there at the time of writing) consisting of replacement foam baffles and glue.

(edit 9/9/2020: A decent repair video published this year)

Armed with these and a screwdriver, I set about it. Taking photos before disconnecting anything to make sure I could reconnect properly…

Then it is time to get rid of the old foam, held in place by glue in addition to being clamped to the speaker case. Firm but delicate screwdriver action required, especially where the foam is glued to the cone…

Since the foam had denatured it was quite difficult to clean away from the metal frame.

Kicking myself when a slip of my scraper slightly damaged the left part of the cone – though not enough to go through, and not damaging performance in any detectable way.

That done, glue applied around the metal frame and to the back of the cone, and the new flexible foam pressed into place and reassemble…

End result – looking like speakers again, and more importantly sounding crisp and clear.

Posted by creacog, 0 comments
22
Jan
2019

Team ideas = development opportunities

A great video by Ableton showing what I consider to be an inspirational, positive, Product and Development environment. As my mindset shifts from ‘Project’ to ‘Product’, I feel this shows how the team’s knowledge and instincts provide a rich a source of product development ideas. After-all they are already signed up to the mission.

  • Agile makes it possible: (from 2 minutes) Transforming to best practice and an agile development culture improved code quality and development flexibility
  • Hack sprint: (from 6 minutes)
    • Every 5th sprint is a ‘Hack Sprint’, ‘hack’ ideas are put forward, teams formed and concrete demo’s built
    • Demos are presented back and pitched for roadmap inclusion

How this approach contributes to a positive culture of continuous improvement is clear from the video; company, product and personal.

Update: 9/9/2020, I noticed that unfortunately the video had been taken private. I am leaving this post in the hope it might become public once more.

https://www.youtube.com/watch?v=tILlZRLhBJE

Posted by creacog in Developer, Product management, Sounds, 0 comments
14
Jul
2009

resurrected my tascam porta 05

(Update: 9/9/2020 – higher resolution images)

Tascam Porta 05

Tascam Porta 05

Decided to dig out my old Tascam Porta 05 ministudio in order to digitise some old 4-track recordings. But, found that the play heads seemed to be stuck in the forward position. Full symptoms and notes:

  • Power on ok
  • Impossible to insert a cassette due to the position of the heads
  • Can hear the motor (which turns all the time power is on – this is normal)
  • Motor responds correctly to the pitch control
  • Fast forward button works – spins the central right capstan
  • Rewind button works – spins the central left capstan
  • Tape heads in forwards position, but the rubber wheel in front of the stop button is not forward enough to press against the metal capstan
  • The metal capstan, which should normally be spinning all the time the machine is powered is not actually spinning
  • Pressing play or record buttons does nothing – the central capstans that would fit into the tape spindles do not turn

I did google around trying to find a solution. I did find a couple of people with the same problem, but no solution posted. I googled for the service manual with no result other than someone in the states selling on ebay for around $22. I wish companies like this would get their service manuals PDF’d and onto the web – shouldn’t be an issue for what is essentially obsolete equipment?

Anyway, with no solution available from the outside, I decided to take a quick look inside to see if there was anything obviously out of place. Getting inside is easy:

  1. Remove the 5 screws from the back panel
  2. Carefully part the two sides noting that:
    • The power on/off slider will likely drop out as it detaches from the internal control
    • all the other sliders remain with the top of the case – but some detach in the process from the underlying control which remains in the base.
    • In my case the forward position of the tape heads was preventing the sides from separating. Pressing them back by pressing the plastic between the erase and write heads made enough space.

Inside the Tascam Porta 05

Close-up showing heads fixed forward

With the sides parted, I then powered up and observed the mechanics when pressing the various control buttons. I couldn’t see anything obvious, but then noticed that underneath the controls is a flywheel attached to that capstan in-front of the stop button. The flywheel is belt-driven and was not spinning.

Nudging the fly-wheel with a cotton-bud.

Using a cotton bud, I gave it a few nudges, attempting to pushing it round in either direction. I was quite surprised  after a few attempts when the belt picked up and the flywheel turned under the power of the motor. At the same time the heads snapped back into the retracted position, and the play and record buttons now worked.

All that remained was to give it a good clean-out and reassemble. Taking care to align the Record function sliders with their underlying controls, and get the 5 screws back in, and I am back in action with kit that I thought was pretty cutting edge back in 1987.

Posted by creacog in Personal, Sounds, 66 comments