2.1 TDA2030 amp from ebay

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#41
interesting
i assumed bass, treble and volume
not an issue as the only source is from my pc via a usb dac...
Actually makes things simpler as i had intended to make the pots available externally to the case, its better being locked away as i have a toddler who likes to get involved in everything....
yer if it didn't have the potentiometers on it i would have just assumed it to be a pure power amp
thanks
 
#42
Whew I am slow. Took three trips to two different Radio Shacks before I finally got the transformer I wanted to use. Got suckered in to "We expect a shipment on Friday." Specs are 25.2 VAC 2 amps center tapped at 12.6. Almost everyone here is serious when it comes to powering a device. I wanted something that would eliminate the normal nags. I figure ~1.4x12.6 or 17V to 18V This is well within the specs of the TDA2030 and should be able to get the amp to full power if I get the other problems solved.

I would rate this as a complete disaster so far. My previous observations with a transformer I had laying around that just produced enough DC voltage to meet the bottom of the specs still show it works at the bare minimum of voltage but the 2 amp power supply just about melted everything. Even at the lowest volume, the amp goes into thermal shutdown with squeals, pops, oscillation, and whistles.

I ordered a number of parts for a weak test matrix. Direct replacement TDA2030s from a different supplier, TDA2040s, and LM1875. I figure this will answer a couple of questions I and others have posed. First if there are counterfeit TDA2030s on eBay, second and third is are the latter two devices truly plug compatible. I know they should be but in reading a lot of material people that say they want to substitute seldom get back with "I did and it worked."

All devices arrived and are in hand. Kind of disappointed there isn't a socket for a pentawatt chip but I can see how this makes sense on several levels. I'll start desoldering tonight and should have some more results shortly.
 
#43
I use the same power supply in mine, you won't get it to full power as it needs a 18-0-18 which are not easy to find and when you do they cost 40 bucks for some reason.

That said on my system the transformer you have works fine, you'll want 4 ohm speakers for the L & R and an 8 ohm for the sub.
I tried 8 ohm for L & R and it works but the little amp seems to prefer 4 ohms better.

I'm hoping I can figure out the crossover and lower it down to 100hz, it is too high where ever it is set at and the sub woofer volume is really touchy on mine.
 
#44
An externally hosted image should be here but it was not working when we last tested it.

Seeing if I can link picture file from FB. Didn't work. The picture is a TDA2030, TDA2040, and the TDA2030 I got with the kit. It could be the printer was running out of ink that day but for now I am saying counterfeit part.

All tests were done with a 2"x3" Al heatsink, 5x7 cm for metrically inclined. This was absolutely necessary as anything above a whisper would get hot.

First off, everything runs hot. If someone wants to say defective design it is OK by me. The main thing is the 2030 that came with the kit would not take over +-12V w/o overheating. At 12V it had a really odd response to the volume knob, nothing from low level then suddenly it was like it was putting out .3 Watts per channel. At 17V it would go into thermal shutdown with the volume off.

The TDA2030 from a different supplier worked at +_17V from no volume up to what I would guess approximately 5 Watts.

The 'good' TDA2030 and TDA2040 performance was almost identical. The 2040 seemed to offer a bit more head room for taxing musical pieces. Still, both could be made to go into thermal shutdown and ran hot. We are talking comfortable listening levels were the most they could put out. I know, they should have been identical at a given voltage, just not what I saw.

The LM1875 gave the best performance. Sound output was just enough to make your ears ring, something not recommended of course. Probably a solid 10-12 Watts at no detectable distortion. These ran very HOT at that sound level. The heat sink was almost too hot to touch. Could be they just set the thermal shutdown a bit higher. Given the suspect parts and these had the National Semiconductor stamp and performed better, I would say substitute them for any TDA2030, TDA2040, TDA2050, design.

I'm somewhat put off by the performance of this amp. Just generates too much heat at idle and volume. I'm going back to class D amps. I like the efficiency and low current draw much better. I think I spent $22 on parts to corner this beast.

I did manage to blow one TDA2030 by shorting the output. Coordination strikes once every 19 seconds! Anyway, I have 4 good TDA2030 + the 2 counterfeits, and 2 TDA2040 left over from this jerking around. If someone wants to fool around with them and sends me a self addressed envelope, they can have them. I am keeping the LM1875s as the amp works OK with them albeit hotter then a pistol. First forum reply gets the parts.
 
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#45
its the lm1875 variety that i shot for
still haven't fired mine up yet, but a little disheartened so far be the comments, but hey we live and we learn
if it turns out to be total garbage, i only shot £15 at it
ive got a 10x20cm heatsink to put the lm1875's on, planning to run at 17v ac
 
#47
I also had problems with the ICs supplied in the kit, They ran very hot with no signal, the amplifier taking more than 2A on each rail when fed with a bench power supply at +/- 12V. I complained to the ebay vendor that they were not up to spec. and I was sent a replacement set but they were just the same. The odd thing was that they said I should not have run it off a bench power supply with current limiting but from a transformer. Had I done this it probably would have gone up in smoke as I have a 150W transformer to supply the board.
I bought 4 LM1875s from RS and all is fine now, less than 350mA with no signal.
Another issue with this board is the HF decoupling capacitors close to the chips are missing so I soldered the necessary 0.1µF ceramic capacitors on both rails for each amplifier.
The Zobel network capacitor fitted to the PCB is only 0.1µF rather than the recommended 0.22µF so I changed that as well.
I guess this amplifier is not without its problems but once fitted with genuine ICs seems to perform quite well.
 
#49
Hi guys, recently I bought and assamble this same kit from ebay (it's a clone but overall it looks the same), the thing is that I'm having a hard time finding a speaker for the subwoofer and I have another couple questions that maybe someone here could help me with as I'm not that good with electronics.

1. As I said before, what specs should I be looking for the subwoofer speaker? Currently I'm using a 7 inch, 6 ohm, around 50 watt woofer (not sub) but I can't crank the bass too much because it starts to sound awful

2. I'm using a 24v 3A transformer (center tapped so it gives 12V-0-12V). Is this enough? I hope so cause I had a really hard time finding anything bigger than 1.2A

3.When I crank up too much the subwoofer volume the leds on the board starts to dimm with the kicks of the speaker. I think it's speaker related but could it be that it ain't getting enough amps?

I'm attaching some pics of my assembled board:

DSC_0012.JPG

The board before Assembly


IMG_20131107_122307.jpg

Here you can see it has 2 leds, both turn on an keep that way

DSC_0041.JPG

Assembled, fitting for some connections and ON/OFF switch still pending


DSC_0048.JPG

The heatsink was from a 1.8ghz pentium 4 computer the base is made of copper (with some kind of silver coating) The fan runs on a separate DC 6V adapter
 
#50
You are at the bare minimum with respect to your transformer. That is, the kit is sold at 18+18+36 Watts and your transformer is 24VAC @ 3 amps or 72 Watts. What's heat is Watts j/k! Chip amps are not 100% efficient, a lot of what they use is just wasted.

John8's post about his amp taking 2 amps at 12V on each rail at IDLE is a good example. That would mean he is using up 24 Watts of transformer<actually for test he used bench supply> just sitting there with the volume off. If yours is doing something similar, you only have ~48 Watts of supply left to run your 72 Watts of amplifier. Just tossing out a ballpark guess, amps other then class D are only about 70% efficient. That means by the time your getting sound out of your speakers, you only have ~30 Watts available from your 72 Watt amp.
 
#51
ricortes said:
You are at the bare minimum with respect to your transformer. That is, the kit is sold at 18+18+36 Watts and your transformer is 24VAC @ 3 amps or 72 Watts. What's heat is Watts j/k! Chip amps are not 100% efficient, a lot of what they use is just wasted.

John8's post about his amp taking 2 amps at 12V on each rail at IDLE is a good example. That would mean he is using up 24 Watts of transformer<actually for test he used bench supply> just sitting there with the volume off. If yours is doing something similar, you only have ~48 Watts of supply left to run your 72 Watts of amplifier. Just tossing out a ballpark guess, amps other then class D are only about 70% efficient. That means by the time your getting sound out of your speakers, you only have ~30 Watts available from your 72 Watt amp.
Click to expand...

I see john8's complaints where about the ICs being counterfeit, when I first tested my kit, I was trying some speakers I had laying around and one was busted. I ended up hooking that speaker to the subwoofer output and blew an IC, a friend of mine gave me a couple TDA's he had laying around. It can't be appreciated on the photo but I replaced both sub woofer IC's for two Telefunken TDA2030.

Also at first I tried hooking up only the subwoofer without the other speakers and it behaved just the same around the same volume level (before and after the replacements)

Also the speakers work great with or without the subwoofer.

Sorry if my comments could be a bit confussing I'm trying to be as clear as possible. 😱
 
#52
When I first powered mine up I blew the sub section but I was running a 4 ohm speaker DUH? and small heat sinks with no fans, it worked fine till I decided to crank it.

I noticed on mine the sub volume is super touchy, Say off is at 7 o clock between 8 & 9 it will start distorting a 10" 8 ohm speaker in my bass cabinet and drowning out the mains set at 12 which seems to be where they start distorting with 4 ohm speakers. My tone control prefers noon-1 with the speakers I am using.
I just figured I was running out of power supply using the 12.6-0-12.6 at 2 amps.

I have a 18-0-18 at 2 amps I may wire up one day but right now I'm busy with other projects. The board and with the transformer, case, connections I figure I have close to 80- bucks in this and it was a fine experiment. I bought 2 boards and I plan on tweaking the second one once it gets too cold to play outside.
 
#53
Jsixis said:
When I first powered mine up I blew the sub section but I was running a 4 ohm speaker DUH? and small heat sinks with no fans, it worked fine till I decided to crank it.

I noticed on mine the sub volume is super touchy, Say off is at 7 o clock between 8 & 9 it will start distorting a 10" 8 ohm speaker in my bass cabinet and drowning out the mains set at 12 which seems to be where they start distorting with 4 ohm speakers. My tone control prefers noon-1 with the speakers I am using.
I just figured I was running out of power supply using the 12.6-0-12.6 at 2 amps.

I have a 18-0-18 at 2 amps I may wire up one day but right now I'm busy with other projects. The board and with the transformer, case, connections I figure I have close to 80- bucks in this and it was a fine experiment. I bought 2 boards and I plan on tweaking the second one once it gets too cold to play outside.
Click to expand...

Just as you said, my sub volume is usually around 7 to 8 o clock, my tone is at noon and the main volume at 10-11 o clock

I have 2 4ohm (20 watt) speakers and the 6ohm woofer as sub. The heatsink without the fan working gets warm gradually and I didn't want to risk blowing something, with the fan it gets barely warm (we've been having kind of a fresh weather in my country, so I'll figure out on summer if it really works)

I tried a diferrent 6ohm woofer from a Sony speaker (Maximum input power
80 Watt) and it seems to work a bit better and when the subwoofer volume is louder (past 9 o clock) even as the speaker distorts the leds don dimm as much as before. I have a 2ohm ceramic resistor, would it be better if I make the sub 8 ohm?

I salvaged a lot of stuff so I think I just invested US around $29.75... the transformer was the mos expensive item ($14.25)
 
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#54
Lights dimming is the power supply running out of juice. One could add more capacitors for storage of bigger power supply. For me what I bought this amp for I can live with the inadequate power supply because I can always turn on a bigger amp if I want one.
It still sounds better then the $40 2.1 system that came with my computer so I'm happy
 
#55
I agree. I'm very impressed with the sound quality as it is right now as I had an USB powered 2.1 system I got last year as a christmas gift...

I tried hooking that subwoofer but as Usual I couldn't get past 9 o clock

Which capacitors could improve this? the two biggest ones right next to the AC input?
 
#57
srmoska said:
I see john8's complaints where about the ICs being counterfeit, when I first tested my kit, I was trying some speakers I had laying around and one was busted. I ended up hooking that speaker to the subwoofer output and blew an IC, a friend of mine gave me a couple TDA's he had laying around. It can't be appreciated on the photo but I replaced both sub woofer IC's for two Telefunken TDA2030.

Also at first I tried hooking up only the subwoofer without the other speakers and it behaved just the same around the same volume level (before and after the replacements)

Also the speakers work great with or without the subwoofer.

Sorry if my comments could be a bit confussing I'm trying to be as clear as possible. 😱
Click to expand...

My comments will lack specifics so their value is limited.

Generally speaking when you go to higher resistance speakers you would want to go up in your power supply VAC. That is if you are using a 25.2 VAC transformer with 4-6 Ohm speakers, you would want to go with ~40 VAC to power 8 Ohm speakers. That is one of the reasons the higher voltage parts are available i.e. the TDA2040 & TDA2050. It may just be me, I would be happy with what you have chosen so far. If you did go the route of replacing the transformer and chip amps while keeping the same speakers, some knucklehead could blow them out seeing how loud your amp will go. Keeping what you got gives you a safe system. Only thing that could blow would be the transformer and you get lots of warning with distortion and lights dimming before that happens.

You have found the efficiency of speakers, decibel advice given in another post, with your substitution. Another generalization, for every 6 decibels increase in efficiency, there is a doubling in the perceived volume. If the ratings of one speaker is 84 decibels and another is 90 decibels, the second speaker will sound twice as loud at the same power output of the amp.

Your transformer is on the weak side. Once again, it is only capable of putting out 72 Watts of power. Chip amps are only ~70% efficient<even when they are working right!> so the most power you will be getting into the speakers will be on the order of 50 Watts. There is nothing wrong with this as it gives you a good level of safety for what can get destroyed.

If you do want more sound volume from the system, the most secure way to do it is with efficient speakers at 4 Ohms as that would be best choice given your transformer and TDA2030 chips. Next best would be to find something like a 25.2 VAC 6-8 amp transformer. Thing is, when you do that you should add fuses to the power supply and speakers! If someone twists the volume knob to 11, something expensive could blow.
 
#59
ricortes said:
My comments will lack specifics so their value is limited.

Generally speaking when you go to higher resistance speakers you would want to go up in your power supply VAC. That is if you are using a 25.2 VAC transformer with 4-6 Ohm speakers, you would want to go with ~40 VAC to power 8 Ohm speakers. That is one of the reasons the higher voltage parts are available i.e. the TDA2040 & TDA2050. It may just be me, I would be happy with what you have chosen so far. If you did go the route of replacing the transformer and chip amps while keeping the same speakers, some knucklehead could blow them out seeing how loud your amp will go. Keeping what you got gives you a safe system. Only thing that could blow would be the transformer and you get lots of warning with distortion and lights dimming before that happens.

You have found the efficiency of speakers, decibel advice given in another post, with your substitution. Another generalization, for every 6 decibels increase in efficiency, there is a doubling in the perceived volume. If the ratings of one speaker is 84 decibels and another is 90 decibels, the second speaker will sound twice as loud at the same power output of the amp.

Your transformer is on the weak side. Once again, it is only capable of putting out 72 Watts of power. Chip amps are only ~70% efficient<even when they are working right!> so the most power you will be getting into the speakers will be on the order of 50 Watts. There is nothing wrong with this as it gives you a good level of safety for what can get destroyed.

If you do want more sound volume from the system, the most secure way to do it is with efficient speakers at 4 Ohms as that would be best choice given your transformer and TDA2030 chips. Next best would be to find something like a 25.2 VAC 6-8 amp transformer. Thing is, when you do that you should add fuses to the power supply and speakers! If someone twists the volume knob to 11, something expensive could blow.
Click to expand...

Thanks for the reply Ricortes, it's been very useful the feedback from you guys.

Maybe later I'll try to replace the transformer (or the capacitors). For now I'll have to settle with my current setup (I'm a married man with a limited income trying to survive the holidays)

My final Setup is the following:

- 2.1 Tda 2030A amp kit (replace default subwoofer ST ICs with telefunken 2030 ICs)
- 24V 3A Transformer with center tap (12-0-12)
- For the Mid/treble: RCA speakers (with tweeter) from a home thather (20 watt 4 Ohm each)
- For the subwoofer: Sony SS-M33 Speaker without the tweeters (just the 80 watt 6 ohm woofer, but with a 2 Ohm ceramic resistor to make it 8 Ohm)

At first I was using the Sony speaker with a generic speaker cabinet... the bass was sounding just awful... I found the original cabinet at my parent's and the bass improved A LOT (really A LOOOOOOT)

I like a lot the results so far, when I was in my early teens I was always trying to mix and repair parts from old audio systems and this proyect really brought back those memories 😀

I only paid for the kit, knobs and trasnformer, everything else was scrapped so I was very cheap

The sound is amazing. I Like my music to be loud and I had very crappy 2.1 USB speakers before this kit so it was a huge improvement.
 
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