The only reason to use IXFN140N20P is if you wanted to run them at 100W each, and I am no longer sure how reliable they would be long term, many of the IXYS N channel Polar mosfets suffer from hotspots.
64N10L2 does not have this problem.
Either way 64N10L2 is better.
In this design we don't need huge amounts of current as it can do Class AB, unlike mu-follower.
64N10L2 does not have this problem.
Either way 64N10L2 is better.
In this design we don't need huge amounts of current as it can do Class AB, unlike mu-follower.
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Actually, I asked a guy in Germany about them - "ha" (here on Diya) who lives close to the factory and he bought them locally and sent them on - you do get stung with the internal taxes so not cheap but nowhere near the price of the Powertron ones on Hifi Collective in England (10GBP ea).
The ones I got are known as the PBH but I thought about trying to get the SMD version that are a lot cheaper and just soldering 'legs' on them to go through the holes in the pcb.
I wrote to Elfa and they said I could just order them online and pay for them electronically but I couldn't get the site to confirm the sale - I unfortunately don't know anyone up there to ask a favour.
I also tried to get them thru Conrads in Germany but they're a basket case for 'non-Eu' online purchases.
Then I found some Isabellenhutte Manganin wire in Russia (insulated) from many years ago and make up my own in lower resistance range with multiple parallel wires for power resistors like the familiar 0.47R, etc - I found 2 main resistance values of approx 9R/meter and the very thin 365R/Metre and used that to make up things like 220R, 1kR particularly for gate stopper resistors where the sound difference is very noticeable.
The lower power resistors are available from Farnells (Element 14 in Oz) but can be obtained directly from a company called Rhopoint - very good people to deal with and more reasonable prices too. I think a company called 'General Resistors' make them.
The Manganin wire is available in England and the US (Shore) but mostly bare wire, no insulation, and not cheap at all - there is quite a bit from China called 6J12 and sometimes goes by the strangely misleading term of Shunt Manganin 47 - it has the same Nickel 3%, Manganese 12% and Copper 85% and heavy insulation - There was one company (Ohmalloy Material Co., Ltd) that made this with insulation.
They also make a slightly different version called 6J13 that has a higher Nickel content and has a brighter sound - called Shunt Manganin 43 - confusing, eh!
Ohmite also makes Manganin SMD resistors (for current sense use) but haven't found any of values like 0.47, 0.68, etc
Hope this helps.
The ones I got are known as the PBH but I thought about trying to get the SMD version that are a lot cheaper and just soldering 'legs' on them to go through the holes in the pcb.
I wrote to Elfa and they said I could just order them online and pay for them electronically but I couldn't get the site to confirm the sale - I unfortunately don't know anyone up there to ask a favour.
I also tried to get them thru Conrads in Germany but they're a basket case for 'non-Eu' online purchases.
Then I found some Isabellenhutte Manganin wire in Russia (insulated) from many years ago and make up my own in lower resistance range with multiple parallel wires for power resistors like the familiar 0.47R, etc - I found 2 main resistance values of approx 9R/meter and the very thin 365R/Metre and used that to make up things like 220R, 1kR particularly for gate stopper resistors where the sound difference is very noticeable.
The lower power resistors are available from Farnells (Element 14 in Oz) but can be obtained directly from a company called Rhopoint - very good people to deal with and more reasonable prices too. I think a company called 'General Resistors' make them.
The Manganin wire is available in England and the US (Shore) but mostly bare wire, no insulation, and not cheap at all - there is quite a bit from China called 6J12 and sometimes goes by the strangely misleading term of Shunt Manganin 47 - it has the same Nickel 3%, Manganese 12% and Copper 85% and heavy insulation - There was one company (Ohmalloy Material Co., Ltd) that made this with insulation.
They also make a slightly different version called 6J13 that has a higher Nickel content and has a brighter sound - called Shunt Manganin 43 - confusing, eh!
Ohmite also makes Manganin SMD resistors (for current sense use) but haven't found any of values like 0.47, 0.68, etc
Hope this helps.
I just had a look on eBay and there seems to be quite a bit on offer but I did notice that a few that I looked would need to be checked as some people can't seem to tell the difference between Isotan/Constantan and Manganin wires - don't think they're 'dodgies' but just don't know - the wire I found was clearly labelled "Isabellenhutte"
Yes, they have collected a pretty good list of components over the years and their delivery service is pretty good - prices are 'not-so-good' but it might work out cheaper overall (with the mail, delivery time) to just get them from England - you only need a couple for the F6 and can use them again if you want.
The Powertrons are recently promoted as a combination with Vishay, etc so might be available elsewhere too - I haven't followed up on this
The Mundorf Ultra's (the MREU) are the same thing as the Powertrons, Isabelleh PBH, etc and yes, are 30% more expensive - they'll even send you a pretty heatsink and isolation material but no bolts/nuts/shoulder washers for an extra 5 GBP! The advertising is a bit misleading.
The Supreme's are the 'same-o' copper/nickel - plenty of those around at a more reasonable price - the use of the Copper/Nickel on some systems can quite useful for the extra 'lift' in the mids/tops.
The Powertrons are recently promoted as a combination with Vishay, etc so might be available elsewhere too - I haven't followed up on this
The Mundorf Ultra's (the MREU) are the same thing as the Powertrons, Isabelleh PBH, etc and yes, are 30% more expensive - they'll even send you a pretty heatsink and isolation material but no bolts/nuts/shoulder washers for an extra 5 GBP! The advertising is a bit misleading.
The Supreme's are the 'same-o' copper/nickel - plenty of those around at a more reasonable price - the use of the Copper/Nickel on some systems can quite useful for the extra 'lift' in the mids/tops.
It works, but not as well as IRFP240 in the default circuit. I tested it a while back.
If we use the same voltage and current then it performs pretty much the same at 1W but worse at 10W and above. Probably at least partly due to to the capacitance getting worse at less than 15 VDS.
If you, however, are considering building an F6 Turbo with say +- 30V or more (but remember to cascode the input buffer or reduce the voltage in some other way) and then the result might be different.
So basically, if you are sizing the circuit up and need the extra dissipation then go for it. If not then I'd stay with the IRFP240. If you need just a little bit more dissipation then consider using the IRFP150 or the IRFP250 which is basically 2x IRFP140/IRFP250 in parallel. And since each side is still a single package you don't have to worry about matching.
Tranny Hum!
Hey There,
I recently finished an F6 but I can’t get rid of a very low level 60hz transformer hum heard through the speakers.
I have tried rerouting wires, twisting wires, plugging it into the mains without a ground, removing the preamp, and so far nothing has worked.
As you can see in the picture, I have the transformer mounted vertically and it is suspended over the chassis. The bracket is bolted to the faceplate and the chassis floor. My grounds are wired just like many others I have seen here.
Any ideas? Thanks! -Glen
Hey There,
I recently finished an F6 but I can’t get rid of a very low level 60hz transformer hum heard through the speakers.
I have tried rerouting wires, twisting wires, plugging it into the mains without a ground, removing the preamp, and so far nothing has worked.
As you can see in the picture, I have the transformer mounted vertically and it is suspended over the chassis. The bracket is bolted to the faceplate and the chassis floor. My grounds are wired just like many others I have seen here.
Any ideas? Thanks! -Glen
Attachments
Hi picoDumbs - The bracket is steel, but due to the way I rigged this up, rather than turning it around I would have to add a new piece of steel to the other side to see if that helps. I’ll try.
You mean physically shielding the Jensen transformers with like a shroud around them?
I built the Troels SBA-761, so they’re around 90 DB.
The amp sounds great with these speakers. With music playing you don’t hear the hum but I know it’s there and I need to get rid of it!
