Audiolab 8000A blown phono input

Increddiboy · 23rd October 2005, 02:08 AM

I recently purchased a second hand 8000A via ebay. On the whole, it's great - love it. came to use my turntable tonight, and when I powered up, set input to phono, there was a buzzing / clicking on the left channel. Since then, I get no or little output on the left channel. If Turn the volume way up, I can hear crackling on the left channel.

Setting the record to phono and listening through my MD player achieves the same result.

Rather than pay someone to fix this, I'd like to do it myself. So, when I take the lid off, what should I be looking for?

wintermute · 23rd October 2005, 02:14 PM

Hi Increddiboy,

I'm not 100% clear on something.... after trying the phono, is the amp not working on the left channel on any source?? or is it just on phono that you have a problem??

buzzing/clicking and then nothing sounds like something arcing to me... might not be though... could be a dry or loose joint/connection. 1st thing to look for is anything that looks burnt

also look for caps with bulges or oil leaking out of them. Also check the phono jacks for loose wires (assuming they arnen't pcb mount).

I fixed a pioneer rondo 4000 my parents own about 5 years ago, was a blown transistor in the phono stage (I can't remember how I tracked it down, but possibly as suggested below).

If you can't see any obvious faults, check the volatages at each transistor in the working channel (base emittor and collector) write it down, and then start comparing with the faulty channel. Note a difference in voltage doesn't mean the transistor itself is faulty, could be a passive, but it will give you an area to look in

Tony.

Increddiboy · 23rd October 2005, 09:41 PM

The problem only exists on the phono channel - all the other pre-amp stages in the 8000a are working fine.

Did a little more investigating this morning. The problem is replicated irrespective of the cartridge type selected (MM or MC). Opened the box up and had a good look at the components. I didn't any obviously burnt out components.

Looks like it'll have to be a methodical investigation of the phone pre-amp stage then...

23rd October 2005, 02:08 AM	#1
Increddiboy diyAudio Member Join Date: Oct 2005	Audiolab 8000A blown phono input I recently purchased a second hand 8000A via ebay. On the whole, it's great - love it. came to use my turntable tonight, and when I powered up, set input to phono, there was a buzzing / clicking on the left channel. Since then, I get no or little output on the left channel. If Turn the volume way up, I can hear crackling on the left channel. Setting the record to phono and listening through my MD player achieves the same result. Rather than pay someone to fix this, I'd like to do it myself. So, when I take the lid off, what should I be looking for?

23rd October 2005, 02:14 PM	#2
wintermute just another diyAudio Moderator Join Date: Aug 2003 Location: Sydney Blog Entries: 22	Hi Increddiboy, I'm not 100% clear on something.... after trying the phono, is the amp not working on the left channel on any source?? or is it just on phono that you have a problem?? buzzing/clicking and then nothing sounds like something arcing to me... might not be though... could be a dry or loose joint/connection. 1st thing to look for is anything that looks burnt also look for caps with bulges or oil leaking out of them. Also check the phono jacks for loose wires (assuming they arnen't pcb mount). I fixed a pioneer rondo 4000 my parents own about 5 years ago, was a blown transistor in the phono stage (I can't remember how I tracked it down, but possibly as suggested below). If you can't see any obvious faults, check the volatages at each transistor in the working channel (base emittor and collector) write it down, and then start comparing with the faulty channel. Note a difference in voltage doesn't mean the transistor itself is faulty, could be a passive, but it will give you an area to look in Tony. __________________ Any intelligence I may appear to have is purely artificial! Some of my photos

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23rd October 2005, 09:41 PM	#3
Increddiboy diyAudio Member Join Date: Oct 2005	The problem only exists on the phono channel - all the other pre-amp stages in the 8000a are working fine. Did a little more investigating this morning. The problem is replicated irrespective of the cartridge type selected (MM or MC). Opened the box up and had a good look at the components. I didn't any obviously burnt out components. Looks like it'll have to be a methodical investigation of the phone pre-amp stage then...

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