Hi Everyone,
I have picked up a faulty NAD310, ive traced the fault to the output stage, a failed BUK555-60B. This device seems to be obsolete and other than used or possibly new counterfeit devices, im looking for a modern alternative device.
Has anyone had to repair/replace one of these before? if so, what did you use?
I am considering trying an IRL540N, but other than a similar power rating and similar Vgs theyre not a perfect match and i dont want to turn this amp into a big Oscillator, or damage anything else in the process of trying to repair it.
Thanks in advance, any thoughts welcomed 🙂
Taylor
I have picked up a faulty NAD310, ive traced the fault to the output stage, a failed BUK555-60B. This device seems to be obsolete and other than used or possibly new counterfeit devices, im looking for a modern alternative device.
Has anyone had to repair/replace one of these before? if so, what did you use?
I am considering trying an IRL540N, but other than a similar power rating and similar Vgs theyre not a perfect match and i dont want to turn this amp into a big Oscillator, or damage anything else in the process of trying to repair it.
Thanks in advance, any thoughts welcomed 🙂
Taylor
Ive never used or heard of these people.
But they came up in a ddg search that says they have stock.
worth a shot ?
https://www.win-source.net/products/detail/nxp/buk555-60b.html
https://www.digipart.com/part/BUK555-60B IC
But they came up in a ddg search that says they have stock.
worth a shot ?
https://www.win-source.net/products/detail/nxp/buk555-60b.html
https://www.digipart.com/part/BUK555-60B IC
I think those guys are likely commercial sellers - like they sell to other suppliers down the supply chain in minimum quantities of say 100, 500 or perhaps a leftover quantity. You may get a polite refusal or no reply at all unless you are waving a fist-full of cash.
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Back on topic, we should note that there's only a single mosfet there in the output stage, paired as the complement to a bipolar power transistor in order to give the audio output a distinct warmness. Yes, its an "effects amp" and sounds quite good too. Otherwise, it would have had a typical complementary BJT pair - in this case, probably 2SB817/2SD1047.
I don't think it would be very critical which exact type of mosfet you used, so long as it was an older style, logic level type (i.e. VGS 1-2V) with equal or somewhat higher current and voltage ratings and is a regular mosfet - not a low Rds trenchfet, for example. IRL520 looks like a candidate to me but it might be wise to match the change in the other channel, once you have the broken one working satisfactorily. Others here might like to comment.
I don't think it would be very critical which exact type of mosfet you used, so long as it was an older style, logic level type (i.e. VGS 1-2V) with equal or somewhat higher current and voltage ratings and is a regular mosfet - not a low Rds trenchfet, for example. IRL520 looks like a candidate to me but it might be wise to match the change in the other channel, once you have the broken one working satisfactorily. Others here might like to comment.
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Hi Taylor ,
If my memory serves me correctly, I have one of those amplifiers who a friend failed to repair, I managed to find the issue which was a shorted ceramic capacitor On a power rail , both channels now work but the friend had stripped some components which makes it not worth continuing with , however if you have a complete 310 & still have not resolved your fault, U possibly could make one good one out of the parts remaining.
I will attach some pictures if U R interested.
William
PS I’m currently away from home so won’t be able to facilitate until after May 4
Hiya,
I bought some IRL540N as it's the closest alternative I could find.
An eBay part did work but i struggled to bias the amp correctly as the Vgs was seemingly higher and I couldn't get enough adjustment.
So I've bought some from Farnell and waiting for them to arrive.
Thanks,
Taylor
I bought some IRL540N as it's the closest alternative I could find.
An eBay part did work but i struggled to bias the amp correctly as the Vgs was seemingly higher and I couldn't get enough adjustment.
So I've bought some from Farnell and waiting for them to arrive.
Thanks,
Taylor
Ok ,
Let me know if it works , I’m sure someone else will need to follow in your footsteps.
I check what else my friend replaced in it before he gave up. He may have also replaced the FeT but I’m sure I saw the BUK55 as I had to look it up as I hadn’t seen it before , very odd design.
There’s is a back up option if you have issues with your main board.
Let me know if it works , I’m sure someone else will need to follow in your footsteps.
I check what else my friend replaced in it before he gave up. He may have also replaced the FeT but I’m sure I saw the BUK55 as I had to look it up as I hadn’t seen it before , very odd design.
There’s is a back up option if you have issues with your main board.
Hi All,
Just a follow up, as per my above posts, initially i bought some IRL540N's from ebay. With these fitted i struggled to bias the amp correctly, the 100R trimmer was at the end of its adjustment but quiscent current was still out of spec (low).
I desoldered them and on a cheap component tester the Vgs was outside the specs on the datasheet. In hindsight i suspect the 100R trimmer couldnt raise the gate voltage enough to actually bias it correctly.
I then ordered some from Farnell. When these arrived i tested them on the same component tested which reported good results, with a Vgs within spec. edit - i want to add that i specifically used the IRL540N and not the IRL540.
Soldered them in, easily biased the quiscent current... spot on. Sounds great and so far after a fair few hours use theyve been reliable and i think a good alt. part!
Just a follow up, as per my above posts, initially i bought some IRL540N's from ebay. With these fitted i struggled to bias the amp correctly, the 100R trimmer was at the end of its adjustment but quiscent current was still out of spec (low).
I desoldered them and on a cheap component tester the Vgs was outside the specs on the datasheet. In hindsight i suspect the 100R trimmer couldnt raise the gate voltage enough to actually bias it correctly.
I then ordered some from Farnell. When these arrived i tested them on the same component tested which reported good results, with a Vgs within spec. edit - i want to add that i specifically used the IRL540N and not the IRL540.
Soldered them in, easily biased the quiscent current... spot on. Sounds great and so far after a fair few hours use theyve been reliable and i think a good alt. part!
'Good to know that you can use the revamped "N" suffix version mosfets without adverse effects in the little NAD310. It seems to be a blanket change in technology for all the old IRF series, allegedly to improve switching speed. AFAIK, only Vishay/Siliconix still manufacture original versions which you can easily obtain if you are open to buying from other suppliers.
The champion of mosfets here, Nelson Pass, doesn't seem to like the idea of "N" suffix parts for linear audio though. They'll also be comparatively fragile as discussed earlier in the thread.
The champion of mosfets here, Nelson Pass, doesn't seem to like the idea of "N" suffix parts for linear audio though. They'll also be comparatively fragile as discussed earlier in the thread.