Tibo PA150 Power Amp…..very much a truly nice budget surprise!

[audio_tony]

VID_20260416_203947790

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[Absolute Concept]

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[Absolute Concept]

Shock and horror, you were right after all that it has IRS 2092 on the back.
The solder joints are clean, there are no traces of smoke on the components.
I need a more powerful magnifying glass to see better.

 

[audio_tony]

I had a look at the audio from your video in a spectrum analyser earlier but it's just wideband noise. It's also possible that your capture is cutting off some high frequency content above 20kHz. Ideally, you need to observe the output with a scope - BUT - ensure that speaker (-) is also common to ground (according to the IRS 2092 datasheet it is).

I'm curious about those additional two transistors on each end of the heatsink - I'm wondering if they are voltage regulators.

It might be worth reverse engineering the circuit around those two transistors. We know from the datasheet that the mosfets are the output drivers - and it's unlikely Tibo would have deviated from the datasheet.

The transformer has multiple secondaries, two of which are 43v - these will be for the power amp section - so you can expect to see +/-60vDC on the FETs - there also seems to be two variations of "typical application diagram" in the datasheet which is odd.

I'd suggest the first thing to do is to identify what those two outlying TIP transistors are doing with a bit of reverse engineering (they might even be +/-15 regulators for the opamps) - easy to check - just measure (on ohms range) from the 15v line to each transistor (with the amp **OFF**) to see if there is continuity there. If so, then you can eliminate those transistors from your fault finding, as you've already established that your +/-15v lines are ok.

I have attached the datasheet for the IRS2092. I doubt you'll get any service info form Tibo (if they even still exist...).

 

[Absolute Concept]

I don't know if it's possible for a power resistor that is silicone-bonded to the transistor to melt the transistor case.
I can't read the one on the left, and the one on the right says TIP 31C
The 2 resistors wrapped in silicone and bonded to the two transistors have 1.8 Kohm
I also posted a picture of the white silicone, the black part is where it was glued to the transistor, the resistor remained pure white.

 

[audio_tony]

Well that transistor has 'popped' for some reason (most likely whatever caused the OPAMP to pop - or - the transistor failing caused the opamp to pop...

The complement to a TIP31C is a TIP32C - but - we don't yet know if one is a PNP and the other NPN.

What you need to check:

See where the collector (center terminal) or emitter (right hand terminal as it faces you) is connected to - you'll probably need to remove the faulty transistor if it's dead short. Looking at the underside of the PCB, it looks as though that could be quite challenging.

Glancing over the PCB suggests that both transistors are the same (a quick glance suggests the tracks link back to the 2092 IC).

Without a schematic though...

 

[Roland68]

I don't know if it's possible for a power resistor that is silicone-bonded to the transistor to melt the transistor case.
I can't read the one on the left, and the one on the right says TIP 31C
The 2 resistors wrapped in silicone and bonded to the two transistors have 1.8 Kohm
I also posted a picture of the white silicone, the black part is where it was glued to the transistor, the resistor remained pure white.

Well that transistor has 'popped' for some reason (most likely whatever caused the OPAMP to pop - or - the transistor failing caused the opamp to pop...

The complement to a TIP31C is a TIP32C - but - we don't yet know if one is a PNP and the other NPN.

What you need to check:

See where the collector (center terminal) or emitter (right hand terminal as it faces you) is connected to - you'll probably need to remove the faulty transistor if it's dead short. Looking at the underside of the PCB, it looks as though that could be quite challenging.

Glancing over the PCB suggests that both transistors are the same (a quick glance suggests the tracks link back to the 2092 IC).

Without a schematic though...

Try searching for "IRS2092 circuit" in Google Images.
There are a large number of very similar amplifier circuits based on the IRS2092 and two identical transistors.
They are all based on the circuit from the datasheet with minor modifications.

The fact that the output coils are getting hot is a bad sign and shouldn't be happening.

If the effort is too much, you can simply buy two tried-and-tested IRS2092 mono amplifiers with 400-800 watts on AliExpress for about €10 each and replace the defective amplifiers with them.
You would then have to check what components actually belong to the amplifier circuit, disconnect it for now, and use the power supply and preamplifier.

 

[Absolute Concept]

Hello, I'm going to try to replace a few more components on the original board, I have a feeling that I won't be able to do it, because I don't have any electronics knowledge.
If I don't succeed, I definitely want to give up the original board and find a stereo module or two mono ones to mount in the box.
In this case, I would keep only the transformer and eventually I will have to build a filter board for the module.
My problem is that I don't know what to choose because I will have to build around the output voltages of the transformer.If the modules require radiators, I can use them because I can easily get them.
Also, if the transformer allows me, I could choose any type of amplifier, as long as it is something simple to adapt.I can safely use something with LM 3875, LM 3886 ...Or if the transformer helps me, maybe even something class A, I repeat, the aluminum radiator is not a problem.
Not having any knowledge, I would prefer something simple, a module or two to work with the voltages of my transformer.

 

[audio_tony]

Try searching for "IRS2092 circuit" in Google Images.
There are a large number of very similar amplifier circuits based on the IRS2092 and two identical transistors.
They are all based on the circuit from the datasheet with minor modifications.

The fact that the output coils are getting hot is a bad sign and shouldn't be happening.

Good shout on searching the circuit - I found what it possibly this very circuit (or close to).

I already posted the circuit from the datasheet a few pages back - but that was lacking the TIP31 transistors.

This circuit has the TIP31 - my earlier glance over the PCB suggests that this circuit is quite similar to the Tibo.

P.S. I did already say that I thought the output coils getting hot is a bad thing (I'm not that familiar with Class D so my comment was pure speculation).

 

[audio_tony]

Hello, I'm going to try to replace a few more components on the original board, I have a feeling that I won't be able to do it, because I don't have any electronics knowledge.
If I don't succeed, I definitely want to give up the original board and find a stereo module or two mono ones to mount in the box.
In this case, I would keep only the transformer and eventually I will have to build a filter board for the module.
My problem is that I don't know what to choose because I will have to build around the output voltages of the transformer.If the modules require radiators, I can use them because I can easily get them.
Also, if the transformer allows me, I could choose any type of amplifier, as long as it is something simple to adapt.I can safely use something with LM 3875, LM 3886 ...Or if the transformer helps me, maybe even something class A, I repeat, the aluminum radiator is not a problem.
Not having any knowledge, I would prefer something simple, a module or two to work with the voltages of my transformer.

The resulting voltage from the transformer (43vAC after rectification approx. 60vDC) will be way too high for LM38xx chips.

It's also way too high for a typical Class A (heat dissipation will be huge with 60-0-60 supplies).

The best option is an IR2092 kit off Ebay. They are not cheap though.

There are also some Class A/B amps on Ebay which could (just) use a supply of this voltage - however much larger heatsinks would be required.

Class D is the way forward here - but you need a module that can operate on such a high voltage.

The alternative is to replace the transformer with a 30-0-30 unit and then go Class A/B.

 

[Roland68]

Good shout on searching the circuit - I found what it possibly this very circuit (or close to).

I already posted the circuit from the datasheet a few pages back - but that was lacking the TIP31 transistors.

This circuit has the TIP31 - my earlier glance over the PCB suggests that this circuit is quite similar to the Tibo.

P.S. I did already say that I thought the output coils getting hot is a bad thing (I'm not that familiar with Class D so my comment was pure speculation).

View attachment 526390

Personally, I wouldn't spend much money on IRS2092-based modules, as you unfortunately never know how good they are.
Audiophonics offers a fairly well-built mono module for €25.90 (only rated up to 50 volts) and a stereo module for €52.90, but I would prefer the mono module. After that, it gets significantly more expensive.

If you want something really good, take a look at the SE800 mono module from Sylph Audio.
It delivers 600 watts at 4 ohms and 300 watts at 8 ohms (not with your current power supply, but you can upgrade if needed), has very good test results, and with a voltage range of up to +/- 85 volts, your current power supply will be fine.
Of course, you'll need two of these modules and a suitable heatsink (not a large one, these Class D modules are very efficient).
Currently, I don't know of any DIY module with a better price-performance ratio.

After that, you can actually look directly at Hypex, for example at the Hypex UcD400HG HxR 1x400W module.

 

[Absolute Concept]

Regarding the schematic, I also found one that has exactly the components that I have on my board. IRFB 5615, TIP 31C, IRS 2092.
Unfortunately, I don't know how to read a schematic, I basically have two left hands.
I would like the idea of putting other ready-made modules and here I would have preferred something in the voltages of the existing transformer.
I think I would find some variants to build for the rectifier and filter part.
The amplification class would matter less, as long as it sounds good.
I have a main system for better listening.I would have liked this one to be something durable, I have music playing 10-12 hours a day, to play something while I work.
Now of course I don't want the quality of a boombox, I want something above average.
Thanks for the support

 

[Roland68]

View attachment 526510

Regarding the schematic, I also found one that has exactly the components that I have on my board. IRFB 5615, TIP 31C, IRS 2092.
Unfortunately, I don't know how to read a schematic, I basically have two left hands.
I would like the idea of putting other ready-made modules and here I would have preferred something in the voltages of the existing transformer.
I think I would find some variants to build for the rectifier and filter part.
The amplification class would matter less, as long as it sounds good.
I have a main system for better listening.I would have liked this one to be something durable, I have music playing 10-12 hours a day, to play something while I work.
Now of course I don't want the quality of a boombox, I want something above average.
Thanks for the support

Sorry, my post #72 was actually addressed to you.
In it, I listed a few modules with sources that are compatible with your transformer and rectifier with capacitors from your enclosure, so you don't need anything else. You already have a complete power supply, so you don't need to build anything new.
I only selected components that work and offer excellent value for money.

However, I overlooked the IRS2092 mono module; it's only rated up to 50 volts. That leaves only the stereo module for €52.90.That should be compatible with your amplifier and perhaps slightly better.

But I want to emphasize again, I'm not a fan of IRS2092-based amplifiers. This is partly due to their poor measured performance, even with more expensive models that are outperformed by amplifiers that are 40 years old. The second issue is the recurring failures, regardless of the developer, manufacturer, or price range.

The other two modules are significantly better, but also more expensive.

However, if your goal isn't to build a DIY amplifier, but you're simply looking for a good, affordable, and reliable amplifier, then you should consider the better TPA3251/55-based amplifiers.
I can recommend the 3E Audio A5, A5se, A7, A7se, PAM1xx, and PAM2xx. If you're looking for something cheaper, the Topping Mini 300 is also an option.
These components are very robust and often surpass amplifiers costing many times more in terms of both sound and measured performance.

 

[Absolute Concept]

Sorry, my post #72 was actually addressed to you.
In it, I listed a few modules with sources that are compatible with your transformer and rectifier with capacitors from your enclosure, so you don't need anything else. You already have a complete power supply, so you don't need to build anything new.
I only selected components that work and offer excellent value for money.

However, I overlooked the IRS2092 mono module; it's only rated up to 50 volts. That leaves only the stereo module for €52.90.That should be compatible with your amplifier and perhaps slightly better.

But I want to emphasize again, I'm not a fan of IRS2092-based amplifiers. This is partly due to their poor measured performance, even with more expensive models that are outperformed by amplifiers that are 40 years old. The second issue is the recurring failures, regardless of the developer, manufacturer, or price range.

The other two modules are significantly better, but also more expensive.

However, if your goal isn't to build a DIY amplifier, but you're simply looking for a good, affordable, and reliable amplifier, then you should consider the better TPA3251/55-based amplifiers.
I can recommend the 3E Audio A5, A5se, A7, A7se, PAM1xx, and PAM2xx. If you're looking for something cheaper, the Topping Mini 300 is also an option.
These components are very robust and often surpass amplifiers costing many times more in terms of both sound and measured performance.

Thank you very much for your involvement, I see that you have given me many options and I thank you.
I have a friend with electronics skills, he is very busy but I would like to give him some free time to look at my board.
If we don't succeed then I will have to go for one of the recommended options.Look what I found to match the transformer.

https://www.aliexpress.com/item/1005007845681091.html?spm=a2g0o.detail.similar_items.8.40c9R2a6R2a66m&utparam-url=scene%3Aimage_search%7Cquery_from%3Adetail_bigimg%7Cx_object_id%3A1005007845681091%7C_p_origin_prod%3A&algo_pvid=5679e208-caf5-41ab-9684-d369d8676593&algo_exp_id=5679e208-caf5-41ab-9684-d369d8676593&pdp_ext_f=%7B%22order%22%3A%22-1%22%2C%22fromPage%22%3A%22search%22%7D&pdp_npi=6%40dis%21RON%21270.01%21270.01%21%21%21415.47%21415.46%21%400b0fee1217766987714921623d01e2%2112000042499266883%21sea%21RO%210%21ABX%211%210%21n_tag%3A-29910%3Bd%3Ab71a6b2b%3Bm03_new_user%3A-29895#nav-specification

 

[Roland68]

Thank you very much for your involvement, I see that you have given me many options and I thank you.
I have a friend with electronics skills, he is very busy but I would like to give him some free time to look at my board.
If we don't succeed then I will have to go for one of the recommended options.Look what I found to match the transformer.

https://www.aliexpress.com/item/1005007845681091.html?spm=a2g0o.detail.similar_items.8.40c9R2a6R2a66m&utparam-url=scene%3Aimage_search%7Cquery_from%3Adetail_bigimg%7Cx_object_id%3A1005007845681091%7C_p_origin_prod%3A&algo_pvid=5679e208-caf5-41ab-9684-d369d8676593&algo_exp_id=5679e208-caf5-41ab-9684-d369d8676593&pdp_ext_f=%7B%22order%22%3A%22-1%22%2C%22fromPage%22%3A%22search%22%7D&pdp_npi=6%40dis%21RON%21270.01%21270.01%21%21%21415.47%21415.46%21%400b0fee1217766987714921623d01e2%2112000042499266883%21sea%21RO%210%21ABX%211%210%21n_tag%3A-29910%3Bd%3Ab71a6b2b%3Bm03_new_user%3A-29895#nav-specification

You already know my opinion on these modules. You might get lucky, or you might not.
If you buy such modules on AliExpress, make sure there are many purchases and reviews with user experiences. Don't confuse these with store reviews.

You might also find more IRS2092 modules through a Google image search.

 

[Absolute Concept]

Ok, thank you very much.