On Thu, 10 Jul 2008 09:37:17 -0700 (PDT), mrdarrett@gmail.com wrote:
>On Jul 10, 9:00 am, mrdarr...@gmail.com wrote:
>> On Jul 10, 6:46 am, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
>> wrote:
>>
>>
>>
>> > mrdarr...@gmail.com wrote:
>> > > Fascinating reading:
>> > >http://www.irf.com/technical-info/appnotes/an-948.pdf
>>
>> > It's relatively primitive rubbish. OK as an AN but no more.
>>
>> > > (found from here: http://sound.westhost.com/articles/hexfet.htm)
>>
>> > > I've heard that the 2SK1058 is superior for audio, and is the only
>> > > MOSFET spec'ed in Slone's book, but that this MOSFET is currently now
>> > > unobtanium.
>>
>> > Lateral Mosfet instead of vertical. NOT a drop-in replacement.
>>
>> > Lateral Mosfets are indeed considered better for audio but I only know of
>> > 2 sources now (Hitachi having introduced them originally but now withdrawn
>> > them). They are Exicon and Semelab.
>>
(going through some old notes) The Semelab equivalent of 2sk108
is(was) BUZ900P, or USP16N10, depending upon which side of the
Atlantic it is marketed by Magnatec.
http://www.magnatec-uk.co.uk/
RL
Reply by legg●July 10, 20082008-07-10
On Thu, 10 Jul 2008 09:37:17 -0700 (PDT), mrdarrett@gmail.com wrote:
>On Jul 10, 9:00 am, mrdarr...@gmail.com wrote:
>> On Jul 10, 6:46 am, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
>> wrote:
>>
>>
>>
>> > mrdarr...@gmail.com wrote:
>> > > Fascinating reading:
>> > >http://www.irf.com/technical-info/appnotes/an-948.pdf
>>
>> > It's relatively primitive rubbish. OK as an AN but no more.
>>
>> > > (found from here: http://sound.westhost.com/articles/hexfet.htm)
>>
>> > > I've heard that the 2SK1058 is superior for audio, and is the only
>> > > MOSFET spec'ed in Slone's book, but that this MOSFET is currently now
>> > > unobtanium.
>>
>> > Lateral Mosfet instead of vertical. NOT a drop-in replacement.
>>
>> > Lateral Mosfets are indeed considered better for audio but I only know of
>> > 2 sources now (Hitachi having introduced them originally but now withdrawn
>> > them). They are Exicon and Semelab.
>>
>> > Farnell have some of them IIRC. Pricey too but very durable.
>>
>> > Graham
>>
>> Thanks.
>>
>> Why did Hitachi withdraw them?
>>
>> Michael
>
>
>Ah... looks like Renesas bought the line from Hitachi
>
>http://documentation.renesas.com/eng/products/transistor/rej03g0906_2sk1056ds.pdf
>
Renesas is Hitachi Semi Division. Not a technology split between
discrete and integrated, either, though they ARE retiring discrete
part numbers like mad.
RL
Not a big enough quantity seller probably. The TO-3 package versions disappeared
first, sigh. TO-3 provides such a superb thermal interface.
They make SUPERB amplifiers when designed in right but people just want cheap these
days.
Graham
Reply by ●July 10, 20082008-07-10
On Jul 10, 9:00 am, mrdarr...@gmail.com wrote:
> On Jul 10, 6:46 am, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
> wrote:
>
>
>
> > mrdarr...@gmail.com wrote:
> > > Fascinating reading:
> > >http://www.irf.com/technical-info/appnotes/an-948.pdf
>
> > It's relatively primitive rubbish. OK as an AN but no more.
>
> > > (found from here: http://sound.westhost.com/articles/hexfet.htm)
>
> > > I've heard that the 2SK1058 is superior for audio, and is the only
> > > MOSFET spec'ed in Slone's book, but that this MOSFET is currently now
> > > unobtanium.
>
> > Lateral Mosfet instead of vertical. NOT a drop-in replacement.
>
> > Lateral Mosfets are indeed considered better for audio but I only know of
> > 2 sources now (Hitachi having introduced them originally but now withdrawn
> > them). They are Exicon and Semelab.
>
> > Farnell have some of them IIRC. Pricey too but very durable.
>
> > Graham
>
> Thanks.
>
> Why did Hitachi withdraw them?
>
> Michael
On Jul 10, 6:46 am, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
> mrdarr...@gmail.com wrote:
> > Fascinating reading:
> >http://www.irf.com/technical-info/appnotes/an-948.pdf
>
> It's relatively primitive rubbish. OK as an AN but no more.
>
> > (found from here: http://sound.westhost.com/articles/hexfet.htm)
>
> > I've heard that the 2SK1058 is superior for audio, and is the only
> > MOSFET spec'ed in Slone's book, but that this MOSFET is currently now
> > unobtanium.
>
> Lateral Mosfet instead of vertical. NOT a drop-in replacement.
>
> Lateral Mosfets are indeed considered better for audio but I only know of
> 2 sources now (Hitachi having introduced them originally but now withdrawn
> them). They are Exicon and Semelab.
>
> Farnell have some of them IIRC. Pricey too but very durable.
>
> Graham
It's relatively primitive rubbish. OK as an AN but no more.
> (found from here: http://sound.westhost.com/articles/hexfet.htm)
>
> I've heard that the 2SK1058 is superior for audio, and is the only
> MOSFET spec'ed in Slone's book, but that this MOSFET is currently now
> unobtanium.
Lateral Mosfet instead of vertical. NOT a drop-in replacement.
Lateral Mosfets are indeed considered better for audio but I only know of
2 sources now (Hitachi having introduced them originally but now withdrawn
them). They are Exicon and Semelab.
Farnell have some of them IIRC. Pricey too but very durable.
Graham
Reply by Dirk Bruere at NeoPax●July 10, 20082008-07-10
Martin Griffith wrote:
> On Wed, 9 Jul 2008 14:20:31 -0700 (PDT), in sci.electronics.design
> mrdarrett@gmail.com wrote:
>
>> On Jul 9, 2:12 pm, Martin Griffith <mart_in_med...@yah00.es> wrote:
>>> On Wed, 9 Jul 2008 14:01:21 -0700 (PDT), in sci.electronics.design
>>>
>>> mrdarr...@gmail.com wrote:
>>>> On Jul 9, 1:54 pm, Martin Griffith <mart_in_med...@yah00.es> wrote:
>>>>> On Wed, 9 Jul 2008 13:44:16 -0700 (PDT), in sci.electronics.design
>>>> Wow, how did you know the value of 4.7 ohms was wrong?
>>> I'm old.
>>>
>>> Nah, I always look at the ratio of the feedback resistors on
>>> everything...even on my wok
>>>
>>>
>>>
>>>> Michael
>>> martin
>>
>> Wait a minute now I'm thoroughly lost. Did you mean C2 should be 100
>> nF instead of 100 uF? Or R2 should be something else (but surely not
>> in Farads ??? !!! !!! ???) Or that both R2 and C2 are wrong... ???
>>
>> M
> No, it was a sideway reference to thread
>
> Subject: 100nF vs. 0.1uF
>
> but the 4.70R gives the ratio to R6 of 1000:1 ie 60dB, and this is not
Shouldn't that be written "4R7"?
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
Remote Viewing classes in London
Reply by Paul E. Schoen●July 10, 20082008-07-10
<mrdarrett@gmail.com> wrote in message
news:641ae523-9b72-4514-82fe-c2aa74bb355a@z72g2000hsb.googlegroups.com...
> On Jul 9, 1:54 pm, Martin Griffith <mart_in_med...@yah00.es> wrote:
>> On Wed, 9 Jul 2008 13:44:16 -0700 (PDT), in sci.electronics.design
>>
>>
>>
>> mrdarr...@gmail.com wrote:
>> >Fascinating reading:
>> >http://www.irf.com/technical-info/appnotes/an-948.pdf
>>
>> >(found from here: http://sound.westhost.com/articles/hexfet.htm)
>>
>> >I've heard that the 2SK1058 is superior for audio, and is the only
>> >MOSFET spec'ed in Slone's book, but that this MOSFET is currently now
>> >unobtanium.
>>
>> >What is the purpose of the inductor L1 (3 uH, air core) in series with
>> >the speaker?
>>
>> >Any comments in general on the schematic, performance, ???
>>
>> >Michael
>>
>> R7, should that be 100nF or .1uF
>>
>> martin
>
>
> Wow, how did you know the value of 4.7 ohms was wrong?
>
> Also I noticed that the amplifier is powered between -Vdd and -Vdd.
> Now that is unusual... ;-)
>
> And I also noticed that the featured MOSFETs, IRF532 and IRF9532 are
> not available through mouser. Grr...
I can't imagine actually building this amplifier, when you can get a much
better one in a single chip package that costs less than 25 cents a watt
and has built-in protection circuitry and other goodies. If you really must
build a MOSFET amplifier, presumably as a learning experience, I would
suggest simulating it first, as I did. I was also able to use all NMOS for
the power output stage, by using a PMOS to drive it. The simulation shows
flat response 20 Hz to 20 kHz. I have not built it yet, but I think it
should work, and the MOSFETs do not seem to be critical. Here it is again:
Paul
========================================================================
Version 4
SHEET 1 1304 744
WIRE 656 -272 -256 -272
WIRE -416 -208 -672 -208
WIRE -64 -208 -416 -208
WIRE 128 -208 -64 -208
WIRE 480 -208 128 -208
WIRE 128 -160 128 -208
WIRE -64 -144 -64 -208
WIRE 480 -112 480 -208
WIRE -416 -64 -416 -208
WIRE 128 -32 128 -80
WIRE 256 -32 128 -32
WIRE 352 -32 256 -32
WIRE 432 -32 352 -32
WIRE -256 -16 -256 -272
WIRE -256 -16 -320 -16
WIRE -256 16 -256 -16
WIRE -320 32 -320 -16
WIRE 480 64 480 -16
WIRE 656 64 656 -272
WIRE 656 64 480 64
WIRE -672 128 -672 -208
WIRE -64 128 -64 -64
WIRE -64 128 -176 128
WIRE 256 128 256 -32
WIRE 480 144 480 64
WIRE 528 144 480 144
WIRE 624 144 592 144
WIRE 656 144 624 144
WIRE -320 160 -320 96
WIRE -288 160 -320 160
WIRE -256 160 -256 96
WIRE -256 160 -288 160
WIRE -64 176 -64 128
WIRE -16 176 -64 176
WIRE 656 224 656 144
WIRE -112 240 -224 240
WIRE -16 256 -16 176
WIRE 128 288 128 -32
WIRE 256 288 256 192
WIRE 352 288 256 288
WIRE 480 320 480 144
WIRE 480 320 352 320
WIRE -176 336 -176 128
WIRE 256 336 256 288
WIRE 304 336 256 336
WIRE -528 352 -576 352
WIRE -416 352 -416 16
WIRE -416 352 -448 352
WIRE -384 352 -416 352
WIRE -224 352 -224 304
WIRE -224 352 -384 352
WIRE -208 352 -224 352
WIRE 480 352 480 320
WIRE -112 368 -112 240
WIRE -112 368 -144 368
WIRE 32 368 -112 368
WIRE 80 368 32 368
WIRE -288 384 -288 160
WIRE -208 384 -288 384
WIRE 256 400 256 336
WIRE -576 416 -576 352
WIRE -384 416 -384 352
WIRE 32 416 32 368
WIRE 128 416 128 384
WIRE -288 432 -288 384
WIRE 352 432 352 416
WIRE 432 432 352 432
WIRE -64 448 -64 176
WIRE 352 464 352 432
WIRE -672 560 -672 208
WIRE -576 560 -576 496
WIRE -576 560 -672 560
WIRE -384 560 -384 496
WIRE -384 560 -576 560
WIRE -288 560 -288 512
WIRE -288 560 -384 560
WIRE -176 560 -176 400
WIRE -176 560 -288 560
WIRE -64 560 -64 512
WIRE -64 560 -176 560
WIRE -16 560 -16 320
WIRE -16 560 -64 560
WIRE 32 560 32 496
WIRE 32 560 -16 560
WIRE 128 560 128 496
WIRE 128 560 32 560
WIRE 176 560 128 560
WIRE 256 560 256 480
WIRE 256 560 176 560
WIRE 352 560 352 544
WIRE 352 560 256 560
WIRE 480 560 480 448
WIRE 480 560 352 560
WIRE 656 560 656 304
WIRE 656 560 480 560
WIRE 176 608 176 560
FLAG 176 608 0
FLAG -576 352 Vin
FLAG 624 144 Vout
SYMBOL voltage -672 112 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value 40
SYMBOL voltage -576 400 R0
WINDOW 3 -75 232 Left 0
WINDOW 123 24 44 Left 0
WINDOW 39 0 0 Left 0
SYMATTR Value SINE(0 350m 2000 1u 0 0 5000)
SYMATTR Value2 AC 1
SYMATTR InstName V1
SYMBOL nmos 432 -112 R0
SYMATTR InstName M1
SYMATTR Value STD30NF06L
SYMBOL nmos 432 352 R0
SYMATTR InstName M2
SYMATTR Value STD30NF06L
SYMBOL pmos 304 416 M180
SYMATTR InstName M3
SYMATTR Value IRF7205
SYMBOL res 336 448 R0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL res 640 208 R0
SYMATTR InstName R8
SYMATTR Value 4
SYMBOL polcap 528 160 R270
WINDOW 0 32 32 VTop 0
WINDOW 3 0 32 VBottom 0
SYMATTR InstName C3
SYMATTR Value 4700�
SYMATTR Description Capacitor
SYMATTR Type cap
SYMATTR SpiceLine V=35 Irms=2.03 Rser=0.033 MTBF=2000 Lser=0 mfg="Nichicon"
pn="UPR1V472MRH" type="Al electrolytic" ppPkg=1
SYMBOL res 112 -176 R0
SYMATTR InstName R4
SYMATTR Value 2.2k
SYMBOL res 240 384 R0
SYMATTR InstName R1
SYMATTR Value 220k
SYMBOL diode 336 -32 R0
WINDOW 0 -34 32 Left 0
WINDOW 3 42 35 Left 0
SYMATTR InstName D1
SYMATTR Value 1N4148
SYMBOL diode 336 96 R0
WINDOW 0 -38 -28 Left 0
WINDOW 3 40 35 Left 0
SYMATTR InstName D2
SYMATTR Value 1N4148
SYMBOL diode 336 224 R0
WINDOW 0 -33 28 Left 0
WINDOW 3 39 -30 Left 0
SYMATTR InstName D5
SYMATTR Value 1N4148
SYMBOL res 112 400 R0
SYMATTR InstName R3
SYMATTR Value 100
SYMBOL res 16 400 R0
SYMATTR InstName R6
SYMATTR Value 100k
SYMBOL Opamps\\LT1037A -176 304 R0
WINDOW 3 9 107 Left 0
SYMATTR InstName U1
SYMBOL res -432 336 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R12
SYMATTR Value 10k
SYMBOL zener -48 512 R180
WINDOW 0 24 72 Left 0
WINDOW 3 24 0 Left 0
SYMATTR InstName D6
SYMATTR Value BZX84C15L
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res -80 -160 R0
SYMATTR InstName R5
SYMATTR Value 4.7k
SYMBOL polcap -32 256 R0
SYMATTR InstName C4
SYMATTR Value 100�
SYMATTR Description Capacitor
SYMATTR Type cap
SYMATTR SpiceLine V=63 Irms=900m Rser=0.1 MTBF=20000 Lser=0 mfg="Nichicon"
pn="UPH1J101MRH" type="Al electrolytic" ppPkg=1
SYMBOL res -272 0 R0
SYMATTR InstName R7
SYMATTR Value 100k
SYMBOL res -304 416 R0
SYMATTR InstName R9
SYMATTR Value 1k
SYMBOL res -400 400 R0
SYMATTR InstName R11
SYMATTR Value 10k
SYMBOL res -432 -80 R0
SYMATTR InstName R10
SYMATTR Value 1meg
SYMBOL nmos 80 288 R0
WINDOW 3 49 86 Left 0
SYMATTR InstName M4
SYMATTR Value Si4850EY
SYMBOL cap -336 32 R0
SYMATTR InstName C1
SYMATTR Value 10p
SYMBOL cap -208 304 R180
WINDOW 0 24 64 Left 0
WINDOW 3 24 8 Left 0
SYMATTR InstName C2
SYMATTR Value 5p
SYMBOL diode 336 32 R0
WINDOW 0 -33 98 Left 0
WINDOW 3 37 33 Left 0
SYMATTR InstName D3
SYMATTR Value 1N4148
SYMBOL diode 336 160 R0
WINDOW 0 -33 34 Left 0
WINDOW 3 40 94 Left 0
SYMATTR InstName D4
SYMATTR Value 1N4148
SYMBOL cap 240 128 R0
SYMATTR InstName C5
SYMATTR Value 5n
TEXT -176 688 Left 0 !.tran .5
TEXT 40 696 Left 0 !;ac oct 5 20 20000
Reply by Martin Griffith●July 9, 20082008-07-09
On Wed, 9 Jul 2008 14:46:35 -0700 (PDT), in sci.electronics.design
mrdarrett@gmail.com wrote:
>On Jul 9, 2:34 pm, Martin Griffith <mart_in_med...@yah00.es> wrote:
>> On Wed, 9 Jul 2008 14:20:31 -0700 (PDT), in sci.electronics.design
>>
>>
>>
>> mrdarr...@gmail.com wrote:
>> >On Jul 9, 2:12 pm, Martin Griffith <mart_in_med...@yah00.es> wrote:
>> >> On Wed, 9 Jul 2008 14:01:21 -0700 (PDT), in sci.electronics.design
>>
>> >> mrdarr...@gmail.com wrote:
>> >> >On Jul 9, 1:54 pm, Martin Griffith <mart_in_med...@yah00.es> wrote:
>> >> >> On Wed, 9 Jul 2008 13:44:16 -0700 (PDT), in sci.electronics.design
>>
>> >> >Wow, how did you know the value of 4.7 ohms was wrong?
>>
>> >> I'm old.
>>
>> >> Nah, I always look at the ratio of the feedback resistors on
>> >> everything...even on my wok
>>
>> >> >Michael
>>
>> >> martin
>>
>> >Wait a minute now I'm thoroughly lost. Did you mean C2 should be 100
>> >nF instead of 100 uF? Or R2 should be something else (but surely not
>> >in Farads ??? !!! !!! ???) Or that both R2 and C2 are wrong... ???
>>
>> >M
>>
>> No, it was a sideway reference to thread
>>
>> Subject: 100nF vs. 0.1uF
>
>
>oh... ha ha ha
>
>
>> but the 4.70R gives the ratio to R6 of 1000:1 ie 60dB, and this is not
>> a mic amp, so 470 is more reasonable.
>> I'm not that good on power amps, but think it could be improved, s/c
>> protection etc.
>>
>> martin
>
>
>The inductor in series with the speaker is for... ???
>
>-MD
3uH is SFA at audio frequencies, so it has to be to do with stopping
RF getting back in to the fets at RF from pick up with long speaker
cables, another thing, often stated here in sed, is that fets love to
oscillate, and everybody sez put 22Rish in series with the gate as
close as possible. One more thing, the psu, if one fuse blows, it's DC
coupled, hmmm, speaker smoke, yum.
I'll wait for phil from Oz to fill in some more stuff, I find power
amps boring, they are just reasonably fast, low distortion AC power
supplies that people masturbate over when listening to mp3's through
coathanger cables
martin
Reply by ●July 9, 20082008-07-09
On Jul 9, 2:34 pm, Martin Griffith <mart_in_med...@yah00.es> wrote:
> On Wed, 9 Jul 2008 14:20:31 -0700 (PDT), in sci.electronics.design
>
>
>
> mrdarr...@gmail.com wrote:
> >On Jul 9, 2:12 pm, Martin Griffith <mart_in_med...@yah00.es> wrote:
> >> On Wed, 9 Jul 2008 14:01:21 -0700 (PDT), in sci.electronics.design
>
> >> mrdarr...@gmail.com wrote:
> >> >On Jul 9, 1:54 pm, Martin Griffith <mart_in_med...@yah00.es> wrote:
> >> >> On Wed, 9 Jul 2008 13:44:16 -0700 (PDT), in sci.electronics.design
>
> >> >Wow, how did you know the value of 4.7 ohms was wrong?
>
> >> I'm old.
>
> >> Nah, I always look at the ratio of the feedback resistors on
> >> everything...even on my wok
>
> >> >Michael
>
> >> martin
>
> >Wait a minute now I'm thoroughly lost. Did you mean C2 should be 100
> >nF instead of 100 uF? Or R2 should be something else (but surely not
> >in Farads ??? !!! !!! ???) Or that both R2 and C2 are wrong... ???
>
> >M
>
> No, it was a sideway reference to thread
>
> Subject: 100nF vs. 0.1uF
oh... ha ha ha
> but the 4.70R gives the ratio to R6 of 1000:1 ie 60dB, and this is not
> a mic amp, so 470 is more reasonable.
> I'm not that good on power amps, but think it could be improved, s/c
> protection etc.
>
> martin
The inductor in series with the speaker is for... ???
-MD