Hi, I've had trouble free performance for two years till a few weeks back - noise and some hum. It increases and decreases depending on its mood 😛
Replaced the FETs but hasn't helped the noise. I've read the transistor A1266 /A1015 could be a likely problem. The music plays just fine, but with lots of noise. Tried replacing the tubes, didn't help.
What else should I be looking at ? Please help.
Replaced the FETs but hasn't helped the noise. I've read the transistor A1266 /A1015 could be a likely problem. The music plays just fine, but with lots of noise. Tried replacing the tubes, didn't help.
What else should I be looking at ? Please help.
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check the reference voltages
if you have no uncontrollable hum, it is not the FET issue.
Is the problem from both channels ?
if you have no uncontrollable hum, it is not the FET issue.
Is the problem from both channels ?
Are the transistors the problem ? Can I replace with KSP2907ATA PNP Transistor, 600 mA, 60 V.
I can't get the A1015 or A1266 here 😕
I can't get the A1015 or A1266 here 😕
I can send you 1266 . please email me for your address.
please make sure you have a new set of 6L6GH
please make sure you have a new set of 6L6GH
Since these transistors are needed to keep the amp going a few years, I'd like to stock a few of whats compatible.
Could someone please help answer if the KSP2907ATA can replace the A1015 /A1266.
Could someone please help answer if the KSP2907ATA can replace the A1015 /A1266.
Did you check your transistor with your multimeter?
There are a lot of A1266 available . There is a reason to damage your 1266. To replace the 1266 cannot completely to resolve the issue.
please check your TUBe set first
There are a lot of A1266 available . There is a reason to damage your 1266. To replace the 1266 cannot completely to resolve the issue.
please check your TUBe set first
JJ and EH 6L6GC are reliable , inexpensive and good
Those NOS will give you a lot of headache unless you have a tube tester
Those NOS will give you a lot of headache unless you have a tube tester
Thanks Victor. I have a reliable source for tested tubes. The faulty Sylvanias were bought online.
Hi paczeltf, could you please help answer if the A1015/A1266 can be replaced with the 'KSP2907ATA'
I want to get a few commonly available for the future. Any help you provide would be great. Thanks.
Hi paczeltf, could you please help answer if the A1015/A1266 can be replaced with the 'KSP2907ATA'
I want to get a few commonly available for the future. Any help you provide would be great. Thanks.
The KSP2907ATA has a different pinout - EBC, so thats out.
2SA1705 (ECB) looks compatible. Can someone help confirm 🙄
2SA1705 (ECB) looks compatible. Can someone help confirm 🙄
I had an issue with hum and in my case it was a bolt at the volume knob that needed to be tightened.
Hi,
Sorry but I can't recommend active component substitutes without tests. Please contact Elekit for advice. I suspect though that any generic PNP model with the same pin layout, beta and max. working conditions should be ok.
On the other hand, I do not really understand why you would need spare transistors. These components work at low voltage and current, and are connected to high value resistors. If any of there transistors fail then you must have smoked a few resistors already. The FETs in the power supply are a different story.
Thanks for the advise paczeltf. I'm not able to identify any bad resistors with my limited knowledge.
Any in particular I should check. All voltages as per the build guide seem to match as I posted here.
I saw an old post with transistor measurements and when I checked mine, found the difference. Have managed a pair of the A1015, should I go ahead and replace ? Here's the voltages I measured on Q1 & Q2.
Q1 - Base (496mv) | Collector (-8.3v) | Emitter (1.1v)
Q2 - Base (490mv) | Collector (-8.8v) | Emitter (1.1v)
Any in particular I should check. All voltages as per the build guide seem to match as I posted here.
I saw an old post with transistor measurements and when I checked mine, found the difference. Have managed a pair of the A1015, should I go ahead and replace ? Here's the voltages I measured on Q1 & Q2.
Q1 - Base (496mv) | Collector (-8.3v) | Emitter (1.1v)
Q2 - Base (490mv) | Collector (-8.8v) | Emitter (1.1v)
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These values look perfectly fine.
You wrote that you do not have the issue with the NEC pair. Did you try putting back the stock EH tubes?
Old tubes can develop noise.
Yes, I've tried with the NEC pair. The noise is still present.
Should I check voltages on FETs Q3 - Q6 ?
Should I check voltages on FETs Q3 - Q6 ?
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If you hear hum then yes. Even if you have replaced them, it is possible that bad tubes killed the new ones immediately.