Hi,
I am thinking about building an AEM6000 (or 6) which uses Hitachi 2sk176/2SJ56
The Hitachi’s are obsolete and it has been suggested I replace them with Exicon EC10N20/EC10P20.
This raises a few questions,
So I'm hoping someone out there can impart a little wisdom with regard to Mosfet substitution.
Is the replacement of the Hitachi’s with the Exicon's a straight forward substitution?
Ignoring the basics – IE power ratings (feel free to point out they are an issue)
I see that many of the specs listed in the data sheets have not been measured under the same test conditions,
Making it difficult for a direct comparison (for yours truly with minimal understanding).
There are also many small variations - input/output capacitance turn on/turn off time (and possibly more bit's I've missed?)
What should the substitution newbie be looking for, when evaluating options?
Which parameters will have the greatest effect on the performance and stability of the amplifier?
If I use Exicon's in the AEM6000
Do I need to change the value of the source gate capacitor for the n channel devices?
Or any of the source gate RC network on the p's?
or any of the other bits I don't understand?
(Yeh, if you were wondering I did try to come to grips with the original cct description - try is the important word here)
The AEM6000 output schematic is lurking in another post
http://www.diyaudio.com/forums/attachment.php?s=&postid=195177&stamp=1056171351
There have been a number of posts which relate to specific device substitution.
Can those of us with a limited (read none) understanding of electronics apply any rules of thumb when contemplating this type of power FET replacement?
Given any power amplifier
Assume it has a reasonable well designed/stable output stage and was designed for obsolete Hitachi pairs, 2sk176/2sj56 2sk134/2sj49 etc
Can the similarly rated Exicons be used as direct replacements?
Should changes be made anywhere to maintain stability?
How will the Exicon equivalents affect the measured performance, distortion levels, Slew rate etc?
Can these changes be predicted?
Or are changes in these parameters likely to be CCT or bias specific?
Going back to the AEM6000, can I predict/expect a change in the published specs?
Appreciate your thoughts
Thanks
Tony
I am thinking about building an AEM6000 (or 6) which uses Hitachi 2sk176/2SJ56
The Hitachi’s are obsolete and it has been suggested I replace them with Exicon EC10N20/EC10P20.
This raises a few questions,
So I'm hoping someone out there can impart a little wisdom with regard to Mosfet substitution.
Is the replacement of the Hitachi’s with the Exicon's a straight forward substitution?
Ignoring the basics – IE power ratings (feel free to point out they are an issue)
I see that many of the specs listed in the data sheets have not been measured under the same test conditions,
Making it difficult for a direct comparison (for yours truly with minimal understanding).
There are also many small variations - input/output capacitance turn on/turn off time (and possibly more bit's I've missed?)
What should the substitution newbie be looking for, when evaluating options?
Which parameters will have the greatest effect on the performance and stability of the amplifier?
If I use Exicon's in the AEM6000
Do I need to change the value of the source gate capacitor for the n channel devices?
Or any of the source gate RC network on the p's?
or any of the other bits I don't understand?
(Yeh, if you were wondering I did try to come to grips with the original cct description - try is the important word here)
The AEM6000 output schematic is lurking in another post
http://www.diyaudio.com/forums/attachment.php?s=&postid=195177&stamp=1056171351
There have been a number of posts which relate to specific device substitution.
Can those of us with a limited (read none) understanding of electronics apply any rules of thumb when contemplating this type of power FET replacement?
Given any power amplifier
Assume it has a reasonable well designed/stable output stage and was designed for obsolete Hitachi pairs, 2sk176/2sj56 2sk134/2sj49 etc
Can the similarly rated Exicons be used as direct replacements?
Should changes be made anywhere to maintain stability?
How will the Exicon equivalents affect the measured performance, distortion levels, Slew rate etc?
Can these changes be predicted?
Or are changes in these parameters likely to be CCT or bias specific?
Going back to the AEM6000, can I predict/expect a change in the published specs?
Appreciate your thoughts
Thanks
Tony
There are at least two companies or manufacturers distributing or making what was Hitachi Power Mosfets today. They may be broken down by geographic region (seems to be the case). My understanding is that at least *one* of them merely inherited the original Hitachi production line intact. The other I believe is licensed. I think that is what is going on...
At least in the USA, it doesn't seem that easy to find and acquire these parts - at least not at a good price, assuming the big distributors have them or can get them...
But, the answer to your question is that if the specs are the same, the part is the same. I've noticed some "newer" parts which are either higher power, higher voltage or both which have been added to their product range...
It's not my aim to disuade you from building something, but the circuit you showed isn't one that I would personally want to build. For one thing those caps on the Mosfets are too large, imho. Which indicates to me that the amp is marginally stable, and is likely to have fairly poor bandwidth as it stands...
Perhaps you might want to look at some other driver boards and designs... I like the offerings from Erno Borbely for one. http://www.borbelyaudio.com
_-_-bear
At least in the USA, it doesn't seem that easy to find and acquire these parts - at least not at a good price, assuming the big distributors have them or can get them...
But, the answer to your question is that if the specs are the same, the part is the same. I've noticed some "newer" parts which are either higher power, higher voltage or both which have been added to their product range...
It's not my aim to disuade you from building something, but the circuit you showed isn't one that I would personally want to build. For one thing those caps on the Mosfets are too large, imho. Which indicates to me that the amp is marginally stable, and is likely to have fairly poor bandwidth as it stands...
Perhaps you might want to look at some other driver boards and designs... I like the offerings from Erno Borbely for one. http://www.borbelyaudio.com
_-_-bear
Renesas....................
Hitachi and Mitsubishi joined up their semicon divisions according to what I see on the web. They are now Renesas.
Their production line is functioning again and the 2SK1058/J162 and their higher voltage versions 2SK2220(21) /2SJ351(2) (?) and 2SK213.....216/2SJ76...79 are mentioned on their web page.
So it must be just a matter of time before we can get these parts easily ,again.
Cheers,
Ashok.
Hitachi and Mitsubishi joined up their semicon divisions according to what I see on the web. They are now Renesas.
Their production line is functioning again and the 2SK1058/J162 and their higher voltage versions 2SK2220(21) /2SJ351(2) (?) and 2SK213.....216/2SJ76...79 are mentioned on their web page.
So it must be just a matter of time before we can get these parts easily ,again.
Cheers,
Ashok.
Exactly ashok! Some objective comparisons would be of value here. My nested feedback amplifier designs render the sound effectively independent of output device character - lateral or vertical MOSFET or even BJT, they only deliver without colour.
Then it's down to reliability/power delivery/PS efficiency.
Then it's down to reliability/power delivery/PS efficiency.
ashok said:
Hi ashok,
Sorry, I didn't mean to mislead.
No, the two amps are not identical. The S860 has a total of 12 MOSFETS and the PCR800 only 8. The S860 also has 1/4" inputs and the PCR800 RCA. The S860 is a little beefier I think and you may very well be right that other things have contributed to the sound more so than the MOSFET's. I was only sharing that the amp sounds very good and uses the Exicons. I would think if they were poor replacements that this would not be the case. If they weren't soldered in place on the Soundcraftsmen amps I would swap them out in the amps to see how much difference they really make, but that is more work than I am willing to do at this point. I should let folks with more electronic knowledge answer these questions. All I have are my ears and eyes. I have driven a pair of JBL 4425's, a pair of JBL 4411's, a pair of Yamaha NS1000's and a pair of Event 20/20's with these amps, and to my ears, the S860 is better sounding. One note though, the S860 is louder than the PCR800.
Here are my speakers
Blessings, Terry
Guys,
Appreciate the insights
Koryusz, thanks for the offer but definately wanted the higher rated devices if I could find them.
Since starting this thread/looking for substitues, soundvalves has been offering matched hitachi 176/56's on ebay.
So I have taken the plunge.
The price was comparable with my expected landed cost for exicoms, and if the wife finds the bill I will hold fate accountable for my actions.
I don't expect that use of either product will contribute much in overall performance? (None that a simple lackey will notice).
As others have indicated there are many factors involved, layout PSU etc.
But having a low level understanding of fet output stages,
finding the spec'd devices as NOS is a good reason to jump in boots & all.
Now to start the fun stuff.
Finally
Can you ever have 2 many speakers? (assembled and working)
Thanks
Tony
Appreciate the insights
Koryusz, thanks for the offer but definately wanted the higher rated devices if I could find them.
Since starting this thread/looking for substitues, soundvalves has been offering matched hitachi 176/56's on ebay.
So I have taken the plunge.
The price was comparable with my expected landed cost for exicoms, and if the wife finds the bill I will hold fate accountable for my actions.
I don't expect that use of either product will contribute much in overall performance? (None that a simple lackey will notice).
As others have indicated there are many factors involved, layout PSU etc.
But having a low level understanding of fet output stages,
finding the spec'd devices as NOS is a good reason to jump in boots & all.
Now to start the fun stuff.
Finally
Can you ever have 2 many speakers? (assembled and working)
Thanks
Tony
Sources for HAFLER J160 and K1560 subs. PLEASE!
Hey Group,
My HAFLER is in need of a J160 and after reading threads on Exicon nad Magnatek subs and trying to find sources, I am not only confused but running out of options. I found a BUZ900 but no match.
Can anybody recommend any subs to get it running again? I will probably replace both, in both channels knowing it will probably cost me a whole pocket full of sheckles.
Thanks
Jim
Hey Group,
My HAFLER is in need of a J160 and after reading threads on Exicon nad Magnatek subs and trying to find sources, I am not only confused but running out of options. I found a BUZ900 but no match.
Can anybody recommend any subs to get it running again? I will probably replace both, in both channels knowing it will probably cost me a whole pocket full of sheckles.
Thanks
Jim
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