You can still get a lightning adapter for those 30-pin connectors.
$70 tube amp what did i get? (Roth)
- Thread starter Audi0
- Start date
I saw a stereo preamp that used a pair of classic 12AX7 phono stages and a pair of 12AU7 for the line stages. Looks like that should work.
Relatively common in vintage preamps. Again, remains to be seen what their role in this circuit is but the fact that there is a separate power supply is somewhat promising.
Audi0
Super Member
I may know why the p/s have a high failure rate just on a quick Google. Look close. That may be why we are getting the chatter on the relay. Pulled the 2 suspect caps. 80% out of value. Su'scon is on the list for capacitor plague and it fits the time frame. Every cap is su'scon.
Also the to big dummy cap lids on top is where there hiding the transistors to a post.
Also the to big dummy cap lids on top is where there hiding the transistors to a post.
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Audi0
Super Member
I didn't have a small enough 220uf on hand i had to bump to 100v. Parts coming in mail with my order for my other amps. So, the oversized cap is getting replaced. I had a nichicon 100uf 25v. To use for the other cap. Those 2 small vaule caps were a point of failure. The green checked out and the brown did as well.
the 220uf was reading 40uf and the 100uf was reading near squat.
the 220uf was reading 40uf and the 100uf was reading near squat.
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Carbsandcaps
Super Member
Just picked one of these up on a whim it said “no power cord” I figured whatever it’s probably just a 3 prong computer cord. Right? Nope. It’s the whole power supply. I’ll see what it looks like when it shows up but if I decide to keep it in one piece I’ll have to build a power supply for it. I’ve found what the ac taps are for the transformer. But I don’t know what the final dc voltage it needs. Should be a fun one.
Wut dey put in dem tings? Crack it open and have a look.
I could be wrong but I believe these were also labeled under the name "Fatman" iTube amps or probably made by same China factory? Many thousands of Fatman hybrid tube amps similar to this amp with iPhone/iPod docks were sold, they were all the rage on eBay & Amazon about 15 years ago (dare I say) helping the tube market make a mainstream come back.
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Audi0
Super Member
I agree even those had the white gloves that came with those. I even had one.
However I don't know if it came from the same Chinese factory as Fatman.
Audi0
Super Member
100% hybrid. It's runs currently. 2 bad caps fixed. Alot of these amps have bad power supplies from googling.
I did the detective work. These may have capacitor plague as they are full of suscon caps and the timeline fits.
This is a theory only.
If you pick one of these up check the caps for any visible signs of leakage.
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Audi0
Super Member
I got a cheap one of Amazon. It works.
Carbsandcaps
Super Member
Well I received mine in the mail today and while it seems well made, it’s definitely not worth trying to make a power supply for. I’ll put my tail between my legs and use it for parts. At least it still has the Chinese 12ax7’s.
Looks pretty well built. Those aluminum tubes are actually part of the transistor heat sinks for the outputs, like cooling towers. It’s got some decent film coupling caps and a ton of capacitance for the low voltage side in the for of 6 3300uf caps. But everything is crammed in there. No wonder they fail. I’m sure it sounds fine when working but just not worth putting any money into. Here’s some pics if anyone is interested.
Looks pretty well built. Those aluminum tubes are actually part of the transistor heat sinks for the outputs, like cooling towers. It’s got some decent film coupling caps and a ton of capacitance for the low voltage side in the for of 6 3300uf caps. But everything is crammed in there. No wonder they fail. I’m sure it sounds fine when working but just not worth putting any money into. Here’s some pics if anyone is interested.
Lavane
Lunatic Member
Yup. It still had all the original software, manuals and paperwork.A piece of digital history!
These old Apples have a very common failure problem. One of the small 3M tape pieces was.put right over the solder pads of an I.C. chip. The glue on the tape corrodes the board over time. I cleaned the board, replaced the solder and it fired right up.
Interesting. Do you know the part number of that 3M tape?
I'm betting that the MacInstosh wasn't the only electronic place that tape was used.
Lavane
Lunatic Member
I should have stated 3M type tape. It's padded and was used to space or insolate the back side of the main board from the housing. Maybe used to reduce vibration? I have some 3M brand tape like that I bought sometime back, but it's two sided tape. Whatever Apple used back then, the glue turned brown.
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