About TA2022 design designers LJM

[ljm_ljm]

I'm running mine at 24V dual rail. I haven't checked the inductors but other than the temperature of the voltage regulators as already mentioned in this thread, I've noticed that the 4700uF/35V smoothing caps get quite hot too. In fact one of them is showing signs of bulging

Apparently this is caused by 'Bus Pumping'.

Expanation: "A switching amplifier that is single ended (IE not a bridge) will cause what is known as "bus pumping". Energy that is stored in the output inductor has to go somewhere when the output stage switches & as it can't run in a continual loop like the current could in a bridge amp it over charges the main reservoir capacitors."

I'm going to replace them with 6800uF/50V ones.

Despite all this, the amp itself is working fine and sounds OK.

Now, TA2022 Selection 50V 4700UF electrolytic capacitor.Meet the voltage requirements.

 

[jonfrason]

I'm running mine at 24V dual rail. I haven't checked the inductors but other than the temperature of the voltage regulators as already mentioned in this thread, I've noticed that the 4700uF/35V smoothing caps get quite hot too. In fact one of them is showing signs of bulging

Apparently this is caused by 'Bus Pumping'.

Expanation: "A switching amplifier that is single ended (IE not a bridge) will cause what is known as "bus pumping". Energy that is stored in the output inductor has to go somewhere when the output stage switches & as it can't run in a continual loop like the current could in a bridge amp it over charges the main reservoir capacitors."

I'm going to replace them with 6800uF/50V ones.

Despite all this, the amp itself is working fine and sounds OK.

Can you check the temperature on your inductors?
As i wrote in the prior post, i changed the inductors for 10uH and changed the LC caps to .22uF, as recomended by tripath.
In fact, the heat has come down a bit. It also takes longer for the inductors sot heat up.

I will do some testing myself. Including short the input (i have quite high hiss/buzz), changing the 4700uF tank caps and add some more smoothing on the output of the transformer (i have connected the transformer directly on the terminals). My caps is quite cool. Do you think changing the caps will have an effect on the inductors?

The relay does not switch off in mute mode anymore!
It did when I first ran the amp on a lower rail voltage, don't remember exactly but i think it was approx 18V dual.
Seems like the amp don't like the voltage range printed on the PCB.

I hope we can find a solution on this heat problem, because i'm about to throw this thing in the bin soon!
(I also have an TK2050 and a TA2020 based amp. No problem with those...)

jon

 

[activexp]

Yes, my inductors get quite hot too

I also have the hiss/buzz. Oddly the buzz disappears when I short the inputs but returns as soon as I re-connect my pre-amp. It looks like the buzz is caused by the pre-amp but if I connect it to a TA2024 amp there is no buzz (or hiss for that matter).

Unfortunately I've been unable to replace the smoothing caps for the simple reason I can't get them out of the board! Even using a desoldering pump they refuse to shift so I've given up with that idea If anyone can suggest a method of removal I like to hear it !

Can't comment on your mute/relay problem. Mine appears to work normally.

I feel the same way as you regarding the heat and noise issues and that it is destined for the bin. Something is going to fail in the not too distant future, that's for sure.

Steve

 

[activexp]

Update

Tried a different pre-amp and the buzz has gone. Still left with some hiss but it's very low level and doesn't intrude.

As I gave up trying to remove the 4700uF caps from the board I've wired the 6800 ones in parallel which hopefully will reduce 'bus pumping' effects.

There's still a heat issue of course but the amp seems quite stable and unaffected.

Bearing in mind the cost of the board I'm generally satisfied with it and the sound quality is excellent to my ears.

 

[Brusque]

Hello Activexp;

> As I gave up trying to remove the 4700uF caps from the board

You can touch the tip of the soldering iron on one of the capacitor terminal, from the bottom of the board. Then, while the solder is melted, you tilt the capacitor to the other terminal side and remove the soldering iron, holding the capacitor tilted untill the solder solidifies again. Now do this to the other pin.

Each time you'll have the capacitor a little raised to the board untill it only have one pin soldered and should be removed very easily. Now clean the board holes with a solder pump and voilà. You're ready to solder the other one in place.

Just be carefull not to get the board very hot. Remember, there's no problem destroying the capacitor but it would be very bad to have the board damaged.

Best regards;

Edson brusque

 

[activexp]

Hi Brusque,

Thanks for the advice. I tried everything you describe but to no avail. One problem is that they're 'snap-in' and very reluctant to tilt from side to side. If they were ordinary radial leads I reckon they'd come out easily.

Cheers,
Steve

 

[Brusque]

Hello ActiveXP!

You can always destroy the component, top to bottom, until you have only the pins on the board.

Use a mid-to-heavy cutting pliers and start cutting it carefully. Destroy the capacitor, not the board.

Best regards;

Edson Brusque

 

[activexp]

Sounds a bit drastic but it's the only way!

 

[ljm_ljm]

Can you check the temperature on your inductors?
As i wrote in the prior post, i changed the inductors for 10uH and changed the LC caps to .22uF, as recomended by tripath.
In fact, the heat has come down a bit. It also takes longer for the inductors sot heat up.

I will do some testing myself. Including short the input (i have quite high hiss/buzz), changing the 4700uF tank caps and add some more smoothing on the output of the transformer (i have connected the transformer directly on the terminals). My caps is quite cool. Do you think changing the caps will have an effect on the inductors?

The relay does not switch off in mute mode anymore!
It did when I first ran the amp on a lower rail voltage, don't remember exactly but i think it was approx 18V dual.
Seems like the amp don't like the voltage range printed on the PCB.

I hope we can find a solution on this heat problem, because i'm about to throw this thing in the bin soon!
(I also have an TK2050 and a TA2020 based amp. No problem with those...)

jon

Please note.Inductance can not be used 10,11 the UH. Must use 22UH.

Otherwise it's very large current

 

[disc]

Dear ljm_ljm,
I bought your TA2022 board ver. 1.2, blue, on ebay. The board I got is somewhat different from the picture on ebay. For instance, mine has a 7810 regulator instead of 100uH inductor! Could you send me a schematic? My email is tumanov@uiuc.edu
Thank you, Alex

 

[disc]

There are 3 voltage regulators on the board (ver. 1.2), all 3 get quite hot. If a toroidal power transformer is used, then it would be quite easy to provide the necessary voltages without straining the regulators and wasting power. About 50 turns of wire gives about 10 volts that can be rectified and connected to 7810. A schematic would be useful to make this adjustment.

ljm, could you post it here? It would be useful to everyone. I hope it is not a secret. In fact I can figure it out myself given the board, but it would be easier it you can provide it.
Thank you. Alex

 

[disc]

It looks like no one is interested anymore in 2022 board!

Since ljm refused to give a schematics, I figured it out myself, at least to the extend I needed it. It annoyed me that all three voltage regulators (+5, +10, and +12v) and both 22uH inductors ran very hot. I added 3 windings to my main power transformer, for about 5, 10, and 12 volts, rectified the AC, and connected to the regulators. I also replaced the 22uH inductors by 11uH inductors recommended by Tripath (44turns on T68-2 core iron powder core).

Now the amp is running cool! I can provide more details if anyone is interested.

 

[marcelmuntean]

It looks like no one is interested anymore in 2022 board!

Since ljm refused to give a schematics, I figured it out myself, at least to the extend I needed it. It annoyed me that all three voltage regulators (+5, +10, and +12v) and both 22uH inductors ran very hot. I added 3 windings to my main power transformer, for about 5, 10, and 12 volts, rectified the AC, and connected to the regulators. I also replaced the 22uH inductors by 11uH inductors recommended by Tripath (44turns on T68-2 core iron powder core).

Now the amp is running cool! I can provide more details if anyone is interested.

I am interested. I have one kit I purchased a while ago and just got around to building it.

 

[disc]

marcelmuntean,

Please let me know if you have any questions. I don't visit this forum very often so you can email me at tumanov at illinois dot edu to get a quick response.

Best,
Alex

 

[litguy]

yes, you are right, I also use this board of ver 1.2
but I think LJM's method is ok
because most people only have +-22V power supply

 

[activexp]

My TA2022 just died

After a few months of relatively infrequent use, the TA2022 amp has died in a puff of smoke, not entirely unexpected due to the heat issues with the voltage regs, inductors and smoothing caps.

I was surprised to see that the only visible damage is a burnt out 6.2 ohm 1 watt resistor, circled in red below:

An externally hosted image should be here but it was not working when we last tested it.

As ljm has not made available schematics it's difficult for a layman such as myself to diagnose the cause of the failure and attempt a repair. Probably uneconomic anyway.

So it's the scrapheap for this board, a shame really as the sound quality was excellent.

 

[mendhi]

PLEASE SUGGEST ME

Dear sir
My self amit from India i am seeing TA 2022 Amplifier on https://sites.google.com/site/stevesstuffproject/Home
this site i am one problem?

I am already buy TA2022 Un-assemble Kit on AliExpress.com - Online Shopping for Electronics, Fashion, Home & Garden, Toys & Sports, Automobiles from China.
like same on your kit but VER 1.2 i am assemble kit but not start my amplifier (no sound) i remover IC TA2022 on the kit and make new PCB different type problem only one speaker are work properly

Than i decide to buy new TA2022 Fully tested ok assemble Kit on AliExpress.com - Online Shopping for Electronics, Fashion, Home & Garden, Toys & Sports, Automobiles from China.

MY QUESTION IS?
TA2022 AUDIO AMPLIFIER AS GOOD SOUND THAN TDA7294 ?. BECAUSE I HAVE ALREADY MAKE TDA7294 AMPLIFIER I HEAR THIS SOUND BUT I HAVE NOT HEAR TA2022 SOUND PROPERLY BECAUSE MY IC IS NOT WORK PROPERLY AND IT IS BURN OUT

PLEASE SUGGEST ME WHICH AMPLIFIER IS GOOD SOUND QUALITY ?.
TA2022 OR TDA7294/93

Regards.

 

[ivanlukic]

I was surprised to see that the only visible damage is a burnt out 6.2 ohm 1 watt resistor

An externally hosted image should be here but it was not working when we last tested it.

If you change that resistor it will probably work again. Find 2W metal oxide resistor that will fit the footprint and solder it so that it is distanced few mm from the pcb.

 

[activexp]

If you change that resistor it will probably work again. Find 2W metal oxide resistor that will fit the footprint and solder it so that it is distanced few mm from the pcb.

Unfortunately I no longer have the board. I passed it on to a knowledgeable friend who volunteered to take a look at it. I've now lost contact with him; he appears to have gone AWOL

 

[Patrick17]

Hi All,

I recently bought this board and I see 50k trim pots. Does anyone know what these are for?

Thanks.