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PostPosted: 11 Apr 2015, 16:36 
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Joined: 11 Apr 2015, 15:55
Posts: 2
Hi All,
I need some help and I have built a few chip amps and tube amps...
Anyway I am on my third kit (all #3663) from IC station. I am using TDA 2030a amp kit #3663 but using most of my own components (but same value listed on their schem). I built a nice chassis for this so I hate to give up on it. Same problem with all three kits.
Amp sounds fine with one speaker (4 ohm) attached to ONE channel- doesn't matter which channel. However when I attach the second speaker (this is a stereo kit) to the other channel I get a loud hum/tone from one of the speakers. Like I said I am on my third attempt... I have an email into IC station but no help so far. Note-I have jumpers on all three of the areas marked for jumpers (L1-L3). Any ideas on what to trouble shoot or has someone experienced this on this layout. 2030 x 2 with tone control layout I have seen others use- I liked the fact that this PCB had space for 4 power caps when many only have two.
Any advice would be appreciated.
Best Regards,
Lendon


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PostPosted: 12 Apr 2015, 16:04 
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Joined: 09 Oct 2012, 19:43
Posts: 293
Location: Vancouver Canada
One thought. You mention your spkr is (4) ohm. The add for the amp says 8 ohms. A 4 ohm spkr would be drawing twice the power and probably making life for one chnl of the amp (and pwr spply), difficult, at best. Doubling the situation by adding the second spkr, (even to the seperate chnl) and not blowing something is a positive testament to the ability of the spkr protection cir's. Put a 4 ohm resister in series with each spkr. This way each chnl will see 8 ohm's which is what the amp is intended to be working with.


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PostPosted: 17 Jul 2015, 14:28 
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Joined: 17 Jul 2015, 14:07
Posts: 3
Hi!
I made a 2 channel stereo amplifier with TDA2030. One channel was working fine but the other one faced a problem. I am attaching the schematics here...
The problem is the resistor R12 (in the 2nd channel according to my schematic) got fried but the R10 was fine. I couldnt make it out whats d problem. I had a dc power supply of 24 volts which was attached to the circuit board which i made at home.
I didnt add any of the transistors in my circuit board although its there in the schematic.
Plz help me out...
Thanks in advance


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PostPosted: 18 Jul 2015, 01:01 
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Joined: 08 Aug 2009, 03:11
Posts: 2225
Location: Chilliwack, BC
If the snubber resistor got fried and C4 isn't shorted, I'd say IC2 is oscillating.

_________________
-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
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PostPosted: 18 Jul 2015, 01:48 
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Joined: 17 Jul 2015, 14:07
Posts: 3
Thanks Gregg!!
I made a mistake in writing the resistor number. It was actually R4(2.2 ohm/ 0.5W) which got fried. But R1 was good, it survived ;).
Is that possible that IC2 is not good(i mean manufacturing defect)? or it might be that i didnot attach a Filter capacitor across the Vcc and Gnd of the IC2 ?
Can it be the reason the R4 resistor got fried although the Second channel was Powered from the same source.
Plz help me...


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PostPosted: 18 Jul 2015, 05:03 
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Joined: 17 Jul 2015, 14:07
Posts: 3
I faced a similar problem. Is there a filter capacitor(approx. 5600uf) across vcc and gnd of the opamps???
If its a no den add 4700uf or 5600uf/35v across vcc and gnd(i.e. pin 5 and pin 3 respectively)of tda2030. Tell me if it doesnt works again.
If possible plz attach a picture of the circuit.


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PostPosted: 11 Aug 2015, 22:55 
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Joined: 09 Oct 2012, 19:43
Posts: 293
Location: Vancouver Canada
- It does sound like it's oscillating.
- I see one 0.22uf (C2) for RF suppression close to R1 but nothing by R4 for other chnl. Add one as close to R4 as possible. (RF oscillation suppression)
- The R6/R16 produce a virtual ground at non-inverting input. So pin-1 of amp should be at 50% supply. If this is off you will be making the amp swing it's output accordingly. {a lot of these amp modules are capable of DC amplification so little in (or off center) means lots out.} It is an amplifier.
- R8, R15, C16 are feedback loop. Check soldering connections to make sure non are open cct (if the loop is open you have a chicken with its tail on fire.)
- check output trans and protection diodes for proper polarity. (Dead short at output stage not good)
- check R12, C4 for polarity and continuity. This leg open could cause the amp to be very unstable,,, and oscillate.
- It could be the module but very doutful as they can take a lot of abuse. Keep checking you will find it.


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