Insight from BA5000 owners please

Sebastien

Active Member
Hi,

I'm looking at bringing a BA5000 into the family, i'm working with the seller over the phone and through photos and videos.

I don't have any problems with the seller, he appears to be a genuine audiophile with a great deal of knowledge and experience in the hobby and many nice audio pieces.

What i'd like to know is anything i can do remotely to health check this amp, it's not in regular use and of course in its 40 odd year life span a lot can happen inside an amp.

Can any existing owners help me here? I'm thinking along the lines of the following;
  • Internal photos
  • Video of it playing
  • Measurement from the speaker outputs with DMM (What range if any am i looking to see here?).
Any other tips would be great - ie fan operation - any tell tale signs with this? Is it supposed to run under quiet listening, or only high output etc.

Thanks for any help on this one!
 
I have never owned a BA-5000, but I did repair one and listened to it afterwards.
Can any existing owners help me here? I'm thinking along the lines of the following;

Internal photos

Along with external pictures, a good idea, they would have to be well lit, in focus, and quite close up to be of any use.
Video of it playing

Almost no use at all, you'll be listening to the recording equipment, and the playback equipment - not the BA-5000 directly. A video of it powering up might help.
Measurement from the speaker outputs with DMM (What range if any am i looking to see here?).
Again - no use at all - this amplifier has transformer output coupling - so you won't see anything of note with a DMM.
Any other tips would be great - ie fan operation - any tell tale signs with this? Is it supposed to run under quiet listening, or only high output etc.

No, the fan isn't supposed to come on at normal household /domestic type listening levels. The thermal switch that controls the fan is specified at such a high temperature that if still 'as standard' it would be a very rare event indeed for it to come on.

Other than that 'you pay your money and you take your chances', part of Vintage Hi-Fi ownership is knowing you will have to do at least some repairs, unless it has been through the hands of a good restorer. Even if part of its description says 'serviced' this isn't worth anything.

If you are buying this from Japan,(as I suspect you are?), you need to check if the unit is capable of being set to your local line voltage (i.e. a multivoltage unit). In this case if it is a fixed lower voltage unit, you'll need to factor-in the purchase of a step down transformer to convert your local line voltage to Japanese '100V only' operation, or whatever voltage it is capable of using. Also if coming from Japan shipping costs will be high because of the extreme weight of the unit, and adequate packaging is absolutely paramount - I recommend it is mounted on a pallet for shipping.
 
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Thanks for the response Hyperion.

I was looking at one in Japan until I saw that the same photos were used in a US auction so I was scared away.

As fate would have it someone in Australia got in touch with me and as we got talking a Ba5000 was rattled off as part of his collection and one thing led to another.

I got some photos of the unit playing last night but nothing high quality yet, he’s having trouble with his camera so only phone pics so far but here’s my big question:

How does the protection circuit work on this unit- the light on the front is red and it’s still playing audio from what I can tell in the photos.

What are the possibilities here?

Thanks very much

I have never owned a BA-5000, but I did repair one and listened to it afterwards.


Along with external pictures, a good idea, they would have to be well lit, in focus, and quite close up to be of any use.


Almost no use at all, you'll be listening to the recording equipment, and the playback equipment - not the BA-5000 directly. A video of it powering up might help.

Again - no use at all - this amplifier has transformer output coupling - so you won't see anything of note with a DMM.


No, the fan isn't supposed to come on at normal household /domestic type listening levels. The thermal switch that controls the fan is specified at such a high temperature that if still 'as standard' it would be a very rare event indeed for it to come on.

Other than that 'you pay your money and you take your chances', part of Vintage Hi-Fi ownership is knowing you will have to do at least some repairs, unless it has been through the hands of a good restorer. If part of its description says 'serviced' this isn't worth anything.

If you are buying this from Japan,(as I suspect you are?), you need to check if the unit is capable of being set to your local line voltage (i.e. a multivoltage unit). In this case if it is a fixed lower voltage unit, you'll need to factor-in the purchase of a step down transformer to convert your local line voltage to Japanese '100V only' operation, or whatever voltage it is capable of using. Also if coming from Japan shipping costs will be high because of the extreme weight of the unit, and adequate packaging is absolutely paramount - I recommend it is mounted on a pallet for shipping.
 
How does the protection circuit work on this unit- the light on the front is red and it’s still playing audio from what I can tell in the photos.
The protection light should turn green for correct operation, it doesn't sound too serious, could be as simple as a failed reed relay? - but may require a fairly skilled tech to find the correct replacement and put it right.
 
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Thanks for the response Hyperion.

I was looking at one in Japan until I saw that the same photos were used in a US auction so I was scared away.

As fate would have it someone in Australia got in touch with me and as we got talking a Ba5000 was rattled off as part of his collection and one thing led to another.

I got some photos of the unit playing last night but nothing high quality yet, he’s having trouble with his camera so only phone pics so far but here’s my big question:

How does the protection circuit work on this unit- the light on the front is red and it’s still playing audio from what I can tell in the photos.

What are the possibilities here?

Thanks very much

I have a sansui ba2000 that had that issue. Ends up someone hooked the led up backwards. So on fire up it was green and then when the speaker relay clicked and sound came on it was red. The plug for the led can go on either way. I simply slipped the connector off and spun it 180 degrees and slid it back on and it works like normal
 
I have a sansui ba2000 that had that issue. Ends up someone hooked the led up backwards. So on fire up it was green and then when the speaker relay clicked and sound came on it was red. The plug for the led can go on either way. I simply slipped the connector off and spun it 180 degrees and slid it back on and it works like normal

Thanks for the reply-

Polarity was my first thought, but there's no green at all. Not sure what to make of it yet, still searching the net.
 
It will only be green for a few seconds on start up. Just like it's normally red for a few seconds. Did you see him turn it on?

Nope i'm still waiting for more footage but from our conversation he isn't seeing any green, just red - but the amp plays which is the curious part...
 
Nope i'm still waiting for more footage but from our conversation he isn't seeing any green, just red - but the amp plays which is the curious part...

Ya that is strange. Maybe like Hyperion said it's a pretty simple issue with the protection circuit. I also don't think it would be anything serious. The color of that light wouldn't sway me away from one of those monsters, specially if it's functional.
 
Ya that is strange. Maybe like Hyperion said it's a pretty simple issue with the protection circuit. I also don't think it would be anything serious. The color of that light wouldn't sway me away from one of those monsters, specially if it's functional.

I'm definitely still pursuing it at this point, it would just be nice to get a better understanding of whats going on with the circuit.

The protection light should turn green for correct operation, it doesn't sound too serious, could be as simple as a failed reed relay? - but may require a fairly skilled tech to find the correct replacement and put it right.

Here's something from the service manual - though i'm not sure if that's relevant to this problem.

Thoughts?
 

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I'm definitely still pursuing it at this point, it would just be nice to get a better understanding of whats going on with the circuit.



Here's something from the service manual - though i'm not sure if that's relevant to this problem.

Thoughts?

Ya I'd say that schematic is pretty worthless unless the amp is in front of you. I can't imagine there much to that protection circuit. If this amp works and sounds even half way decent this would be the very least of your worries.
 
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I’ve read an article that says the Ba5000 has 3 different protection circuits can anyone shed any light on this please?

Thanks
 
3 different protection circuits

I am not sure it has 3 'circuits' as such, unless they count fuses as one 'circuit'.

1.) Current limiting - automatically & progressively shuts off drive to the OP transistors when too much current is being drawn through them.
2.) Thermal protection - provided by a fan, it also shuts off the input signal.

Fuses.
Soft power on.

BTW: I was wrong about the possible cause of seeing no green light, it won't be a reed relay, there is an odd little bit of circuitry that performs the job of turning on first the red LED and then the green, so maybe there is a component failure there.
 
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I am not sure it has 3 'circuits' as such, unless they count fuses as one 'circuit'.

1.) Current limiting - automatically & progressively shuts off drive to the OP transistors when too much current is being drawn through them.
2.) Thermal protection - provided by a fan, it also shuts off the input signal.

Fuses.
Soft power on.

BTW: I was wrong about the possible cause of seeing no green light, it won't be a reed relay, there is an odd little bit of circuitry that performs the job of turning on first the red LED and then the green, so maybe there is a component failure there.

Thanks Hyperion - these protection circuits don't sound as though they would allow the BA5000 to produce audio in protection (?); suggesting that it's likely a problem in the bit of circuitry performing the job of turning the LED green?
We're organising to bring the amplifier to a technician this week so hopefully i'll be able to report back sooner than later- but it's nice to get your opinion too.

Thanks - here's the excerpt i read online.

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I have had a BA-5000 for a few years, and I've a couple of things to add to the discussion. First, this is a VERY heavy beast. Moving it around, taking it to the service shop, etc., requires a very strong back, or two guys. The fan on mine never comes on, no matter how long or how loud I run it. I had it serviced recently, and the tech remarked that it was built with high quality components, and "that's why it has lasted so long, and still sounds good."

Pictures will not show much of the driver boards, but I'd definitely want pictures of the output transistors to ensure they are the correct Sankens, if collectibility is important to you. To do this, the back panel comes off, after some crazy fooling with the fan and housing.

These things are expensive, and I recommend seeing and hearing it in person. Shipping will be a challenge, unless you can somehow drive to where it is located, but I gather it's in Australia, but I have no idea where you are located.
 
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