Hi everyone !
I am a new member on this forum and proud owner of an a3i amplifier.
Unfortunately, when I came back to home late in an evening, I plugged a jack cable in my phone while the amplifier was on and volume control high. This resulted in a loud sound and after no sound at all. A friend help me to diagnostic the problem and found one of the 2SA1216 transistor (Q14) reach very high temperature in a couple of second, which is to remplace to his thought.
I manage to found 2SA1216 transistor from I think is a trusted reseller to avoid fakes: 2SA1216
My questions are the following:
Do I need remplace also the 2SC2922 transistor to matched it with the new 2SA1216 ? And moreover, do I need to remplace also the other pair of 2SA1216+2SC2922 to match it with the new ones ?
Thanks for your help,
Moise
I am a new member on this forum and proud owner of an a3i amplifier.
Unfortunately, when I came back to home late in an evening, I plugged a jack cable in my phone while the amplifier was on and volume control high. This resulted in a loud sound and after no sound at all. A friend help me to diagnostic the problem and found one of the 2SA1216 transistor (Q14) reach very high temperature in a couple of second, which is to remplace to his thought.
I manage to found 2SA1216 transistor from I think is a trusted reseller to avoid fakes: 2SA1216
My questions are the following:
Do I need remplace also the 2SC2922 transistor to matched it with the new 2SA1216 ? And moreover, do I need to remplace also the other pair of 2SA1216+2SC2922 to match it with the new ones ?
Thanks for your help,
Moise
Welcome to the forum.
As they operate in series, it's likely that there is at least some damage (2nd breakdown) to the NPN complement transistor, though these tolerate very high currents. I would check that the driver transistors weren't also damaged at the time. Otherwise you may fit the new part and the same thing happens again and you need to order more components and wait even longer. A basic oscilloscope would be helpful to verify the correct waveforms at various points when you apply a signal and a multimeter is needed to verify the DC voltages around the output stage too, by comparison with the good channel.
Take care with probing power stages - one slip and a short with a probe or other metal object, can do a lot of damage.
As they operate in series, it's likely that there is at least some damage (2nd breakdown) to the NPN complement transistor, though these tolerate very high currents. I would check that the driver transistors weren't also damaged at the time. Otherwise you may fit the new part and the same thing happens again and you need to order more components and wait even longer. A basic oscilloscope would be helpful to verify the correct waveforms at various points when you apply a signal and a multimeter is needed to verify the DC voltages around the output stage too, by comparison with the good channel.
Take care with probing power stages - one slip and a short with a probe or other metal object, can do a lot of damage.
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Hi All
I found this thread a few days ago and spent 2 eves reading every thread to much interest. Today is the 11th anniversary of the original post by xpro(Alex)
I have been on a massive journey hifi wise in the time this thread has been running, getting the addictive upgrade bug which apart from the experience has left me at times with a wonderful hifi but no food in the fridge I don't want to drop any Naims.
I think what I want to say is thanks entirely to a random pickup of a Cambridge audio cd6 from a charity shop in perfect working order took me away from ripping to flac and using streamers and modern stuff to listen through on a brilliantly satisfying and rewarding journey and Ive loved every minute of it.
Cd6 cleaned checked and working then sent me to Bristol to pick up a working secondhand A3i and then the following day to surrey to collect a pair of Rogers LS55 speakers and then at the weekend to Exeter to collect a second hand Cambridge audio DAC, then putting it all together and being knocked sideways with the quality of sound, that journey coupled to this thread and the expertise here which has given me confidence in knowing all of this wonderful engineering can be kept working into the future.
I only bought the cd6 because the rear connections intrigued me, until that point Cambridge audio was just a name I knew but had no experience of.
It has been far more satisfying to put this very budget friendly system together than anything I bought since my first Nad cd and amp which I saved a long time to buy back in the 90's
Thanks to all involved in designing this equipment and all the input in this thread and enjoy your music
I found this thread a few days ago and spent 2 eves reading every thread to much interest. Today is the 11th anniversary of the original post by xpro(Alex)
I have been on a massive journey hifi wise in the time this thread has been running, getting the addictive upgrade bug which apart from the experience has left me at times with a wonderful hifi but no food in the fridge I don't want to drop any Naims.
I think what I want to say is thanks entirely to a random pickup of a Cambridge audio cd6 from a charity shop in perfect working order took me away from ripping to flac and using streamers and modern stuff to listen through on a brilliantly satisfying and rewarding journey and Ive loved every minute of it.
Cd6 cleaned checked and working then sent me to Bristol to pick up a working secondhand A3i and then the following day to surrey to collect a pair of Rogers LS55 speakers and then at the weekend to Exeter to collect a second hand Cambridge audio DAC, then putting it all together and being knocked sideways with the quality of sound, that journey coupled to this thread and the expertise here which has given me confidence in knowing all of this wonderful engineering can be kept working into the future.
I only bought the cd6 because the rear connections intrigued me, until that point Cambridge audio was just a name I knew but had no experience of.
It has been far more satisfying to put this very budget friendly system together than anything I bought since my first Nad cd and amp which I saved a long time to buy back in the 90's
Thanks to all involved in designing this equipment and all the input in this thread and enjoy your music
Welcome to diyAudio. Its good to read a reply from a happy shopper of used gear and we hope you get the bug to do a little DIY building and experimenting too. That's even more fun once you have the basic tools and tackle a small project or two in your search for more enjoyment, and your personal needs. The knowledge you gain can lead you further to an absorbing and very rewarding activity in audio. Who knows how far your new skills could then take you?
Good luck with your A3i. X-pro (Alex Nitikin) produced a number of similar and even more interesting designs for Creek Audio too, back in the day. You might want to look at them for your future interests.
Good luck with your A3i. X-pro (Alex Nitikin) produced a number of similar and even more interesting designs for Creek Audio too, back in the day. You might want to look at them for your future interests.
Thankyou Ian
I totally agree and I’ve always been a keen fan of the smell of solder since my neighbour at the time who worked for Plessey Towcester brought me home a circuit board and some components (duff) to practice with. I was 11 haha. Anyway never took that further, pier guidance wanted the smell out of the house and for me to get a real job.
Anyhow. The thrill is in the chase and I am a confirmed old hifi addict. Please if you get a moment would you pass some details on the other creek/Alex designs you met he referring to.
Kind regards
Shaun
I totally agree and I’ve always been a keen fan of the smell of solder since my neighbour at the time who worked for Plessey Towcester brought me home a circuit board and some components (duff) to practice with. I was 11 haha. Anyway never took that further, pier guidance wanted the smell out of the house and for me to get a real job.
Anyhow. The thrill is in the chase and I am a confirmed old hifi addict. Please if you get a moment would you pass some details on the other creek/Alex designs you met he referring to.
Kind regards
Shaun
It's quite a while since I repaired an A3i for someone, and, as far as i know, it's still working well, despite my not being able to reduce the DC offset in one channel to <10mV. Whilst i didn't chanf=ge all the components mentioned by Alex, no part of the amp. reached anywhere near 95C, nor would I expect such a temperature. Is the quiescent current within the specification in both channels? From what you say it isn't, so I'd be looking for a problem with the o/p transistors or their associated circuitry.
"Learn about the LED problem in earlier posts. But even with
new LEDs in my opinion the LED current is too high and so I
usually replace R16 and R18 with 10k in both channels. The
standard resistors of 3k3 are deteriorated most times and are
in no way 1 watt parts as seen on the board. Check R8 also"
I'll give it a try then, thanks.
10K 1 Watt and the R8 as well?
Sorry, you mean 1/4W for the R8,R16 and R18?
I have some so i can try now, otherwise i'll order 1W ones
Hi, hoping someone might be able to help. I've been the proud owner of an a3i since somewhere around 97. The store I used to use for repair and service had closed down and the amp is not putting out any sound. I have no clue what the issue might be, I've taken the cover off and when I power it up all the led's light up except for led 101. Was wondering if anyone could recommend a repair service near Surrey or offer any help? Thanks in advance. Edit: actually led 101 does light up it's just very faint. I don't have a spare set of speakers to test if it's the speakers.
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Hi!
By the way somebody has a diagram/service manual of Cambridge Audio ATAC3 type power amp ?
Thanks.
Pls send me: zsedelybalazs@gmail.com
By the way somebody has a diagram/service manual of Cambridge Audio ATAC3 type power amp ?
Thanks.
Pls send me: zsedelybalazs@gmail.com
The A3i schematics are available at hifiengine
Cambridge Audio A3i - Manual - Stereo Integrated Amplifier - HiFi Engine
Cambridge Audio A3i - Manual - Stereo Integrated Amplifier - HiFi Engine
How time flies by, 12 years on this thread
Anyway another question about the A3i (working)
Got it working from usual led failure and added/replaced some components acording to X-pro advice and all good and sounding fine but...
One of the Leds is brighter then the other 3, all Leds were matched to each other and all have a 1.95V drop.
Resistors R8- R16 and R18 replaced with 1W ones and 10K for R16/18
Just can't find a logical reason why it should light up brighter then the others (led102)
Any ideas ?
Anyway another question about the A3i (working)
Got it working from usual led failure and added/replaced some components acording to X-pro advice and all good and sounding fine but...
One of the Leds is brighter then the other 3, all Leds were matched to each other and all have a 1.95V drop.
Resistors R8- R16 and R18 replaced with 1W ones and 10K for R16/18
Just can't find a logical reason why it should light up brighter then the others (led102)
Any ideas ?