O2 amp Australian parts GB

[vince3141]

Thanks DDW, my refund came through today

Vince

 

[dontdiewondering]

@hochopeper - No joy, started at 9pm after a few beers and cocked up the first thing I touched so Ive put it away for a day or two. Still waiting for the money from BF...

 

[qusp]

well if you have dramas and cant sort it out yourself, send it here i'll stuff it for you gratis because you deserve a fully functioning amp without too much pain after this

 

[dontdiewondering]

@qusp - thanks for the offer. It I've de-soldered what I stuffed up and will try again next weekend. Hopefully BF transfers the remaining money and I can post the last kit and finalise the refunds.

 

[hochopeper]

hey ddw, any luck with the money from bf or your build yet mate?

 

[dontdiewondering]

No reply to the last 2 messages and the build is finished but... I plugged in an old pair of headphones and they started heating up pretty quick so hopefully tonight will be going over the fault finding section of the blog to see what's gone wrong. Checked for bridges and dr joints but frustration got the better of me do I put it up.

I'll keep trying BF...

 

[dontdiewondering]

@Coolguy - refund sent,
@ Stoiky - Thanks, and
@ Polak - refund sent by paypal, sorry for the delay slipped through the cracks.

 

[qusp]

DDW, mate, sounds like you had some serious DC on the output, mate, DO NOT connect headphones before making sure the amp is working correctly. no problems on the offer, still stands

 

[hochopeper]

Were any of the ICs getting hot? I'd probably pull them all out of their sockets and run through the list of measurements that is in the blog, that'll help you narrow down the location of the problem.

Post a pic up and list the measurements you're getting if you're having any dramas.

 

[dontdiewondering]

Thanks guys, I also got a PM from an observer state-side as well and he said to check R12 & R13. I did the full resistance test with only U2 in and R12 is the culprit (its reading jumps all over the shop). I've desoldered one leg, checked the resistor value and re-soldered it and the DMM is still jumping all over the place. R12 is still sad so I'm about to hunt back the components connected on that run and check those joints.

 

[dontdiewondering]

@MoonShad0w - Have you had any luck getting in contact with BF? I can post the remaining items of his that I have so you can at least have something to hold over him until he gives you his kit.

Thoughts?

 

[MoonShad0w]

DDW - Supposedly he posted my kit last week, I'm just waiting to see if it'll show up this week. Thanks for the offer, though

 

[dontdiewondering]

really? don't know how when I have PCB's and enclosures here, unless he posted the one he had put aside for himself.

 

[hochopeper]

Business as usual in the land of tall tales, fantasy and BF.

 

[dontdiewondering]

Any ideas for the R12 issue?

 

[wintermute]

Hi ddw, I just had a look at the schematic and R12 is in series with a 2.2uF cap so the resistance value will change if measured in circuit as the current from the multimeter flows through to charge that 2.2uF cap. If you leave it long enough that cap will probably fully charge and your reading will stabalise. Changing the level on the volume control will probably also change the rate of change of the resistor reading.

I would expect that you would see something similar happening on R13. If you are not then check the joints on R13, C14, and your volume pot (as the problem may be with those rather than your R12.

Tony.

 

[dontdiewondering]

@wintermute - Thanks for the advice. It was funny that R13 was bang on the expected reading and never moved while R12 never stabilised. I'll have a look tomorrow and see what happens.

 

[hochopeper]

Just tracked down my copy of the schematic ... wintermute's suggestion of looking at C13 and VR1 seem most likely. Does the behaviour change if you remove U3 from its socket?Check the supply rails on U3 as well perhaps?

 

[qusp]

the above sounds like that cap in series with R13 might be the problem as in shorted to ground, or something in parallel with it is shorted to ground. i havent built the amp or studied the schematic, but if one is giving the expected behavior of changing with the pot and as the cap charges, but R13 is not, it seems you have a shorted cap perhaps, which would explain the headphones heating up, if the cap filters the DC.

it really is incredible the idiotic pathelogical ******** BF comes up with, when he knows we are on speaking terms with MoonShad0w. its really incredible hes lasted as long as he has as a scammer

 

[hochopeper]

it really is incredible the idiotic pathelogical ******** BF comes up with, when he knows we are on speaking terms with MoonShad0w. its really incredible hes lasted as long as he has as a scammer

To be fair his scamming style is not always particularly lucrative. Lucky for him kfc still send him a pay cheque, wonder if there is any way to get that pay cheque directed to moonshadow and ddw until their debts are repayed?