Sometime back, I was fortunate enough to find a Pioneer Disco Robo J-7. Some of you can find them in the trash where you live, but here in USA, they are like unicorns or Loch Ness, or Sasquatch... rumored to exist, people talk about them but no one has ever seen one. Well I did, and I bit immediately.
Upon arrival, I discovered that it was in pretty good condition, but has all the idiosyncratic issues common with this set:
First I rebelted the tape deck. It was a rather simple task. Years of experience and familiar with little tricks certainly helped. Otherwise, could have been a bit tedious for a first timer. Although the deck is simple, this is a good thing because it is rock solid reliable. No high effort mechanical levers run it... simply press the electric buttons and they work. FF, RW, Play and Stop. That simple. I like it! After rebelling, no tape speed adjustment was necessary which is a pleasant departure from norm. And I dare say, the deck sounds very good. Probably not the best in terms of hi-fi but I'm just guessing. They are pre-recorded goodwill tapes after all and not $60 metal tapes recorded on high end equipment. Although I can't say if the deck sounds as good as or better than the best existing boombox deck, I can definitely say that it sound better than many many other decks.
Ok, so during my initial testing, I found that the unit can get pretty loud, but it sounded horrible. Lots of distortion and buzzing. No wonder, the speakers, all of them, are rotted out. Need to refoam them all.
Here is one of the speakers sitting next to a Sanyo M9990 driver. It's TINY, but LOOK at the magnet. These drivers weighs like 5 of the Sanyo driver (ok, I'm exaggerating, but not by much). As for magnet strength, lets put it this way: when removing the mounting screws, the screwdriver kept getting sucked up by the magnet (think movies with some poor metal accessorized sap pasted onto an MRI machine turned on). Them are serious magnets!
Here they are, ready to foam. I ordered rubber surrounds, hoping to never do this again. Unfortunately, they sent me foam surrounds. Well, I can't wait so I'm gonna install them. Foam should last like 20 years anyhow so I guess that's good enough for now. When I got something tore down, I'm not exactly a patient person. I also wish the interior diameter of the new surrounds was slightly smaller because the overlap on the cone is a bit small to my liking but I guess I'll just have to be careful. Luckily these speakers are ported and not sealed which would put more stress on the cones/surrounds.
One done, 3 more to go.
All done, ready to reinstall.
Now, on to the crappy fake button membrane.... Unfortunately, time is not kind to this material, as the chemical nature gets unstable. They look like fungus infested toe nails, all alligator skin cracked. But underneath are true good quality switches. Could there be a better solution?
Well, I ordered a couple replacement membranes from a fella in HK. Paid big bucks (big to me). I took one look and said to myself..... uh no. Not gonna use them. If anyone needs one (or both), hit me up, you can have 'em at my cost. Instead, I took to the drawing board to get ideas. I wanted a permanent elegant solution. Not some cheap plastic membrane that belongs on an appliance (think Microwave here).
OK, I'm moving quick so it seems like this is just days right? No, this is months in the process. But here are my prototypes, for checking fit, quality, etc.
Well, unfortunately, I didn't account for the deck door swing and while they fit with the door closed, there is interference when door opens. I need to increase the top bevel and rethink the thickness of the panels. Material feel is good. They are made of nylon with a somewhat sandblasted feel to them but not sandpaper rough -- hard to describe. Buttons work well and fit well into the panel receptacles. Tried operating the switches and they work great! Yes! Anyhow, now that I have proof of concept, I went back to the CAD drawing board to make adjustments. Unfortunately, I can't figure out how to do that so I had to remake them all over again fresh. I initially thought I would paint the pieces to suit but decided to instead order colored pieces. Here are the new pieces:
Success! Fit is good, Look is good. Now time to install onto the top panel. Works perfectly! Buttons/switches all operate with slight light pressure. Feels professional and no longer like a toy. I also like the new color scheme compared to original. I like the way it looks. Check it! I have one extra set of this black/yellow/green/red assembly -- PM me if you are interested in doing the same thing (I also have the two reproduction membranes too that I mentioned above if anyone needs).
Happy to say that this thing is surprisingly loud. It's one of my loudest sets. The amp board contains 2 LA4440 chips (typically used in cars etc) mounted onto a huge heat sink. Datasheet says "typically" 19wpc in BTL mode but at something like 13.2v. As this box is 15V on batteries and probably higher on AC, it's not a stretch to say that this unit puts out 22-25wpc rms easily. I've heard other reviews saying these aren't hifi. But all I can say is that it sounds very very good. Bass is decent because those speakers were designed with high X-Max cones & ported too, and it clearly has no trouble reproducing highs. The only downside is that there is no tone controls. But guess what, while tone controls are usually the first things I want to tweak when I turn on a boombox, surprisingly on this one, the audio is very balanced and I don't find myself looking to adjust it to any significant extent -- sound great as it. Although the tuner looks like an afterthought, and I say this because of the tiny scale, I discovered that it is actually a good tuner, much better than a lot of boomboxes. The small scale probably more a function of no real estate to put a true decent tuner dial scale.
Anyhow, I'm happy as a clam now, and listening as I work! I think this is going to be my new workhorse for music while I work. There's nothing not to like about this thing.
Honorable mentions: I want to thank Eric (Caution) for helping me make up a paint template so I could reproduce the 109db legend on the grill as I wanted to paint the grills due to some blemishes I didn't like.
A lot more work not mentioned went into this restoration, which I'll save for maybe an e-book that I'll write about this adventure. I may also install a bluetooth receiver before I'm done. However, I have no desire to add any disco lites to it. It's a shame that these are so rare here. It has instantly become one of my favorites, and because I have so many boomboxes, that's saying something.
Upon arrival, I discovered that it was in pretty good condition, but has all the idiosyncratic issues common with this set:
- Cassette Deck no longer working
- Foam surrounds, on all 4 speakers, rotted out
- But, most concerning, deteriorated tape button control panel membrane. Cheep-Azz Pioneer, damm them to h*ll for being so dang cheeeep!
First I rebelted the tape deck. It was a rather simple task. Years of experience and familiar with little tricks certainly helped. Otherwise, could have been a bit tedious for a first timer. Although the deck is simple, this is a good thing because it is rock solid reliable. No high effort mechanical levers run it... simply press the electric buttons and they work. FF, RW, Play and Stop. That simple. I like it! After rebelling, no tape speed adjustment was necessary which is a pleasant departure from norm. And I dare say, the deck sounds very good. Probably not the best in terms of hi-fi but I'm just guessing. They are pre-recorded goodwill tapes after all and not $60 metal tapes recorded on high end equipment. Although I can't say if the deck sounds as good as or better than the best existing boombox deck, I can definitely say that it sound better than many many other decks.
Ok, so during my initial testing, I found that the unit can get pretty loud, but it sounded horrible. Lots of distortion and buzzing. No wonder, the speakers, all of them, are rotted out. Need to refoam them all.
Here is one of the speakers sitting next to a Sanyo M9990 driver. It's TINY, but LOOK at the magnet. These drivers weighs like 5 of the Sanyo driver (ok, I'm exaggerating, but not by much). As for magnet strength, lets put it this way: when removing the mounting screws, the screwdriver kept getting sucked up by the magnet (think movies with some poor metal accessorized sap pasted onto an MRI machine turned on). Them are serious magnets!
Here they are, ready to foam. I ordered rubber surrounds, hoping to never do this again. Unfortunately, they sent me foam surrounds. Well, I can't wait so I'm gonna install them. Foam should last like 20 years anyhow so I guess that's good enough for now. When I got something tore down, I'm not exactly a patient person. I also wish the interior diameter of the new surrounds was slightly smaller because the overlap on the cone is a bit small to my liking but I guess I'll just have to be careful. Luckily these speakers are ported and not sealed which would put more stress on the cones/surrounds.
One done, 3 more to go.
All done, ready to reinstall.
Now, on to the crappy fake button membrane.... Unfortunately, time is not kind to this material, as the chemical nature gets unstable. They look like fungus infested toe nails, all alligator skin cracked. But underneath are true good quality switches. Could there be a better solution?
Well, I ordered a couple replacement membranes from a fella in HK. Paid big bucks (big to me). I took one look and said to myself..... uh no. Not gonna use them. If anyone needs one (or both), hit me up, you can have 'em at my cost. Instead, I took to the drawing board to get ideas. I wanted a permanent elegant solution. Not some cheap plastic membrane that belongs on an appliance (think Microwave here).
OK, I'm moving quick so it seems like this is just days right? No, this is months in the process. But here are my prototypes, for checking fit, quality, etc.
Well, unfortunately, I didn't account for the deck door swing and while they fit with the door closed, there is interference when door opens. I need to increase the top bevel and rethink the thickness of the panels. Material feel is good. They are made of nylon with a somewhat sandblasted feel to them but not sandpaper rough -- hard to describe. Buttons work well and fit well into the panel receptacles. Tried operating the switches and they work great! Yes! Anyhow, now that I have proof of concept, I went back to the CAD drawing board to make adjustments. Unfortunately, I can't figure out how to do that so I had to remake them all over again fresh. I initially thought I would paint the pieces to suit but decided to instead order colored pieces. Here are the new pieces:
Success! Fit is good, Look is good. Now time to install onto the top panel. Works perfectly! Buttons/switches all operate with slight light pressure. Feels professional and no longer like a toy. I also like the new color scheme compared to original. I like the way it looks. Check it! I have one extra set of this black/yellow/green/red assembly -- PM me if you are interested in doing the same thing (I also have the two reproduction membranes too that I mentioned above if anyone needs).
Happy to say that this thing is surprisingly loud. It's one of my loudest sets. The amp board contains 2 LA4440 chips (typically used in cars etc) mounted onto a huge heat sink. Datasheet says "typically" 19wpc in BTL mode but at something like 13.2v. As this box is 15V on batteries and probably higher on AC, it's not a stretch to say that this unit puts out 22-25wpc rms easily. I've heard other reviews saying these aren't hifi. But all I can say is that it sounds very very good. Bass is decent because those speakers were designed with high X-Max cones & ported too, and it clearly has no trouble reproducing highs. The only downside is that there is no tone controls. But guess what, while tone controls are usually the first things I want to tweak when I turn on a boombox, surprisingly on this one, the audio is very balanced and I don't find myself looking to adjust it to any significant extent -- sound great as it. Although the tuner looks like an afterthought, and I say this because of the tiny scale, I discovered that it is actually a good tuner, much better than a lot of boomboxes. The small scale probably more a function of no real estate to put a true decent tuner dial scale.
Anyhow, I'm happy as a clam now, and listening as I work! I think this is going to be my new workhorse for music while I work. There's nothing not to like about this thing.
Honorable mentions: I want to thank Eric (Caution) for helping me make up a paint template so I could reproduce the 109db legend on the grill as I wanted to paint the grills due to some blemishes I didn't like.
A lot more work not mentioned went into this restoration, which I'll save for maybe an e-book that I'll write about this adventure. I may also install a bluetooth receiver before I'm done. However, I have no desire to add any disco lites to it. It's a shame that these are so rare here. It has instantly become one of my favorites, and because I have so many boomboxes, that's saying something.
. It's friggen crazy! The bass is not low like a kaboom but it definitely has strong bass and solid. Good midrange, and excellent treble. Royce, don't need no tweeters with this thing, treble is not lacking. In fact, if you wanna, you can listen to and be very very happy with classical music too.