having trouble with buying the avondaleaudio BR as their paypal link did not work and still awaiting email from them.
May just fit a replacement standard bridge in for a start.
Tc
May just fit a replacement standard bridge in for a start.
Tc
Got the avondale bridge now, however, i must ask further questions before i install this. putting in the big capp blew the fuse, should i have put some snubber caps in before the big caps to reduce the load draw, or will a soft start module fitted at the mains end be a better install. i have put the old caps back in and checked everyting. so any advice welcome before i install new bridge and blow it up!
Tc
Tc
It comes with a CD?! Wow. They're schottky, or so was said earlier. I hope it's obvious what to do with any centre tap or mid-point of secondary windings. Should be easy enough to put in, especially with instructions and those nice PCB risers.
yes the there are MBR20200, you can buy just a PCB and fit any diode too.
hexfred were a bit more complicated and from my review were not audio based.
Tc
hexfred were a bit more complicated and from my review were not audio based.
Tc
You might find schottkies are not so hot for auduo either when you hear it. I put them in an amp once and it made it really bright, not something the already-thin PM66KI needs. On the plus side it sounded more "detailed" and "fast".
I hope it works out for the best.
I hope it works out for the best.
bridge is fitted and values are now equal across the bridge. but the fuse still blows. i did when it first blew plugged it in switched on, was this the main issue with the blown fuse as in i have blown something in the mains line pre fuse?
Tc
Tc
Tc, I don't know if this is easy to do but have you tried just connecting the caps and bridge diodes to the secondary (disconnect the rest of the amp) and see if the fuse still blows. The inrush current charging up larger caps will be greater. I assume you're using a time delay fuse ?
update: blows 2 and 2.5 td fuses. the latter fuse does blow less faster. checked all values and while res values are good voltage is tiwce higher in one side than the other.
JonH what to do mean by seconday and disconnecting rest of amp?
sorry for late reply as i have been awaiting fuses.
thanks
Tc
JonH what to do mean by seconday and disconnecting rest of amp?
sorry for late reply as i have been awaiting fuses.
thanks
Tc
>checked all values and while res values are good voltage is tiwce higher in one side than the other.
Voltage is twice as higher on one side than the other of WHAT exactly ?
A transformer has two sides, the primary (input) side and the secondary (output) side.
The fuse is blowing because the current flowing through it exceeds its rating for a sufficient time for the fuse wire to melt.
The supply for the output stage of the amplifier consists of a transformer, a bridge rectifier and a some capacitors. As I understand it you have increased the capacitance from the original design. The capacitors will draw a lot of current when they first charge up (the inrush current). Also if one of the output transistors has failed short circuit this too will allow a large current to flow. Either of these will blow the fuse. I was suggesting you isolate the supply from the output stage to discount this part of the amplifier. Perhaps though it would be much simpler if you just measure the resistance between the positive supply and ground and the negative supply and ground (with the amp off of course) this should be a high reading, if it is less than a few ohms then you have a short somewhere and this is why the fuse keeps blowing. Make some measurements and report back.
Voltage is twice as higher on one side than the other of WHAT exactly ?
A transformer has two sides, the primary (input) side and the secondary (output) side.
The fuse is blowing because the current flowing through it exceeds its rating for a sufficient time for the fuse wire to melt.
The supply for the output stage of the amplifier consists of a transformer, a bridge rectifier and a some capacitors. As I understand it you have increased the capacitance from the original design. The capacitors will draw a lot of current when they first charge up (the inrush current). Also if one of the output transistors has failed short circuit this too will allow a large current to flow. Either of these will blow the fuse. I was suggesting you isolate the supply from the output stage to discount this part of the amplifier. Perhaps though it would be much simpler if you just measure the resistance between the positive supply and ground and the negative supply and ground (with the amp off of course) this should be a high reading, if it is less than a few ohms then you have a short somewhere and this is why the fuse keeps blowing. Make some measurements and report back.
Any luck yet, TC?
If it continues to look grim, let me know if you fancy splitting the cost of getting a second amp off eBay for spares.
I've been on the lookout for a second transformer for quite some time but can't justify shipping an entire working amp to Canada just to cannibalize it. If it comes to it then it would be cool if I could chip in some cash for a sacrificial amp to get shipped to you and then you could forward just the transformer to me.
Let me know,
Ben
If it continues to look grim, let me know if you fancy splitting the cost of getting a second amp off eBay for spares.
I've been on the lookout for a second transformer for quite some time but can't justify shipping an entire working amp to Canada just to cannibalize it. If it comes to it then it would be cool if I could chip in some cash for a sacrificial amp to get shipped to you and then you could forward just the transformer to me.
Let me know,
Ben
Besides toroid and remote, is anyone currently in need of anything if I have to resort to parting out a working amp? I'm looking for someone to receive shipping and forward me just the parts I need. I'd ideally like to avoid a perfectly good chassis ending up in a landfill, but it'd be more than it's worth to ship it whole.
Yeah, there's never any shortage of good working ones for sale. I just want a transformer and remote though. It would cost me far more than the price of an amp to get one shipped from the UK to Canada, and I wouldn't be surprised to get dinged by customs too.
...although if I DID get a whole second amp for spares, I suppose I could play with copper plating the rest of the chassis like Marantz did with the 63DP 🙂
good news - working again, did nothing to it except change the bridge around, so i think the original bridge was broken, then this new one was wrong way and now all works, now to install the coke cans and see if theres any more issues.
thank you for help all
super
Tc
thank you for help all
super
Tc