Marantz 250
Paul Sanchez
located/identified all of them except 2!!!
I can't find any sj2582 or it's substitute. Nor it's "unknown" complement.
Can anyone help.
BTW, I've been all over the web in search of these transistors to no avail.
Any help is appreciated.
Phil Allison
"Paul Sanchez" <clns...@austin.rr.com> wrote in message
news:ijE68.82158$XZ1.3...@typhoon.austin.rr.com...
Paul,
The SJ.... codes from Mororola are secret numbers known only to the
customer and Motorola themselves.
I am not familair with the Marantz 250 so you will have to test any good
SJs to determin the voltage ratings, polarity and even if it is maybe a
darlington type.
Regards, Phil
Trevor Wilson
"Paul Sanchez" <clns...@austin.rr.com> wrote in message
news:ijE68.82158$XZ1.3...@typhoon.austin.rr.com...
**They were Marantz in-house numbers. As such, no documentation, outside
Marantz is available. The devices you are seeking, though, are the
pre-driver transistors. TO-3 package and with a VCER of greater than 130
Volts. The SJ2582 (PNP) can be replaced by a 2SC2238. It's complement, the
2SA968. Both of the replacements are more linear and will allow (slightly)
better performance from your 250. The same devices can be safely used as
driver transistors (coded SJ2586 and SJ2585), as well. Output devices can be
substituted with MJ15003/4 devices. Indeed, the MJ15003/4 devices were used
in later model Marantz 250M amplifiers.
NOTE WELL: All pre-driver, driver and output devices, for the 250 MUST be
hFE matched, to within 30%. Otherwise, reliability and performance WILL be
compromised.
Also important: In a major failure of this model (output devices, etc), look
very carefully at the low(ish) value carbon resistors, R528 & R527. These
can fail, without any visible signs. As can R529 & R530. Though that is less
common. You might also check the relay for damage. Contacts usually weld
together, due to the thoughtless proctection system provided by Marantz (and
most other manufacturers of the time).
--
Trevor Wilson
www.rageaudio.com.au
Trevor Wilson
"Paul Sanchez" <clns...@austin.rr.com> wrote in message
news:ijE68.82158$XZ1.3...@typhoon.austin.rr.com...
**I've just located a Marantz service bulletin, which lists a 2N5682 as a
suitable replacement for the SJ2582 and a 2N5680 for the SJ2583. The usual
hFE matching criteria still apply, though. Personally, I would stick with
the 2SA968/2SC2238, though. They're higher specc'd devices and probably a
good deal more linear. Probably easier to obtain, as well.
--
Trevor Wilson
www.rageaudio.com.au
Phil Allison
"Trevor Wilson" <tre...@rageaudio.com.au> wrote in message
news:vAI68.29798$Ni2.1...@news-server.bigpond.net.au...
>
> NOTE WELL: All pre-driver, driver and output devices, for the 250 MUST be
> hFE matched, to within 30%. Otherwise, reliability and performance WILL be
> compromised.
Trevor,
how do you advise doing device Hfe matching? The process is
different for small signal, driver and output transistors. The usual simple
beta checkers are no good used outside of small signal devices.
BTW Does the Marantz 250 use paralled output devices?
Regards, Phil
Trevor Wilson
"Phil Allison" <bi...@bigpond.com> wrote in message
news:__L68.85563$HW3.1...@newsfeeds.bigpond.com...
>
> "Trevor Wilson" <tre...@rageaudio.com.au> wrote in message
> news:vAI68.29798$Ni2.1...@news-server.bigpond.net.au...
> >
> > NOTE WELL: All pre-driver, driver and output devices, for the 250 MUST
be
> > hFE matched, to within 30%. Otherwise, reliability and performance WILL
be
> > compromised.
>
>
> Trevor,
>
> how do you advise doing device Hfe matching?
**I don't. Nor do I do it. Too hard. I pay to have it done.
The process is
> different for small signal, driver and output transistors. The usual
simple
> beta checkers are no good used outside of small signal devices.
**Correct. Given the fairly average matching, required by Marantz (30% is
hardly onerous) and the quality of my suggested pre-driver and driver
devices, matching at a few mA should be adequate. The outputs will be a
problem, though.
>
> BTW Does the Marantz 250 use paralled output devices?
**Of course. 2 * NPN and 2 * PNP.
--
Trevor Wilson
www.rageaudio.com.au
Phil Allison
Given the fairly average matching, required by Marantz (30% is
> hardly onerous) and the quality of my suggested pre-driver and driver
> devices, matching at a few mA should be adequate. The outputs will be a
> problem, though.
>
> >
> > BTW Does the Marantz 250 use paralled output devices?
>
> **Of course. 2 * NPN and 2 * PNP.
>
*** Paralled bipolar output devices need Vbe/Ic matching not Hfe
matching in order to share current evenly. Seems the Marantz 250 needs both
parameters matched so it will operate within spec - hence the special SJxxxx
numbers selected by the nice people at Motorola.
Regards, Phil
Paul Sanchez
Trevor Wilson
**Actually the SJ number does not indicate the matching spec. The matching
spec is indicated either by the colour with which the SJ number is printed,
or a painted mark on the transistor.
--
Trevor Wilson
www.rageaudio.com.au
Richard Wagner -Dagwood-
special >SJxxxx numbers selected by the nice people at Motorola.*******
I read this with interest as this is the same amp as a 240 which I am
working on.It's also the same as a 1200 Integrated (not sure on number but I do
have the service manual copied.) We have been kicking this amp around a bit on
the NAK users group Stephen Sank of Chamberlin Speakers has worked on them and
we are currently talking about amps that go POOF in the night. Phase Linear,
NAD, Dyan 120, and my all time fav0rite the Flamasauraus oops thats the
Tigersauraus.
On output devices I had the Marantz 240 (which I have and like but baby needs
some new output stages. I have settled on the MOT MJ802/4502 combo is that a
good substitute? On the 240, I'd recommend MJ15024/MJ15025, or MJ15003/MJ15004.
Also there are no nice people at Motorola they've all been laid
off.
Richard
"Tigers Older brother DAG"
Phil Allison
"Richard Wagner -Dagwood-" <ruin...@aol.commenospam> wrote in message
news:20020203201825...@mb-fl.aol.com...
The MJ802/4502 is the same as the MJ15003/15004. Motorola made the
substitution years ago. Remember the fine print that says they reserve the
right to alter and improve without notice etc? Well, they mean it.
There are lots of people still working for Motorola so I expect your
remark is about the brand name change to "On Semiconductor" who act as the
distributor for such items.
Regards, Phil
Trevor Wilson
"Richard Wagner -Dagwood-" <ruin...@aol.commenospam> wrote in message
news:20020203201825...@mb-fl.aol.com...
hence the
> special >SJxxxx numbers selected by the nice people at
Motorola.*******
>
> I read this with interest as this is the same amp as a 240 which I
am
> working on.It's also the same as a 1200 Integrated (not sure on number but
I do
> have the service manual copied.) We have been kicking this amp around a
bit on
> the NAK users group Stephen Sank of Chamberlin Speakers has worked on them
and
> we are currently talking about amps that go POOF in the night. Phase
Linear,
> NAD, Dyan 120, and my all time fav0rite the Flamasauraus oops thats the
> Tigersauraus.
> On output devices I had the Marantz 240 (which I have and like but baby
needs
> some new output stages. I have settled on the MOT MJ802/4502 combo is that
a
> good substitute? On the 240, I'd recommend MJ15024/MJ15025, or
MJ15003/MJ15004.
>
**Don't use the MJ802/4502. Use the MJ15003/4. Particularly if the
MJ802/4502 are NOS items. Those old aluminium case Motorola devices were
absolute crap. The best were the old RCA second sourced MJ15003/4, if you
can find them.
Don't forget to match them.
--
Trevor Wilson
www.rageaudio.com.au
Phil Allison
>
> **Don't use the MJ802/4502. Use the MJ15003/4. Particularly if the
> MJ802/4502 are NOS items. Those old aluminium case Motorola devices were
> absolute crap.
Aluminium (or aluminum) packages were discontinued in about 1985
by Motorola. Recent steel package MJ802/4502 I have checked are the same
chips as used for MJ15003/4 types.
"Absolute crap" is code for Trevor doesn't like them.
They were in fact widely used in hi-fi amplifiers including the Aussie
designed Murray 120 watt modules from Auditec. Most had very high Hfe
figures and the pair gave lower THD residuals in the Murray compared to the
MJ15003/4 replacements.
Regards, Phil
Trevor Wilson
>
> "Trevor Wilson" <tre...@rageaudio.com.au> wrote in message
> news:3um78.34202$Ni2.1...@news-server.bigpond.net.au...
>
> >
> > **Don't use the MJ802/4502. Use the MJ15003/4. Particularly if the
> > MJ802/4502 are NOS items. Those old aluminium case Motorola devices were
> > absolute crap.
>
>
> Aluminium (or aluminum) packages were discontinued in about 1985
> by Motorola. Recent steel package MJ802/4502 I have checked are the same
> chips as used for MJ15003/4 types.
>
> "Absolute crap" is code for Trevor doesn't like them.
**Nope. "Absolute crap" is for the low speed, low Voltage rating, low
linearity and poor thermal cycling ability of the old aluminium cased
MJ802/MJ4502 transistors. I have a report somewhere, written by RCA
engineers, tabling the thermal reliabiliyt of aluminium vs. steel cased TO3
transistors. Steel cased TO3 devices demonstrate far more than ten times the
thermal cycling capability. Likely that is why Motorola changed to steel.
Moreover, RCA variants of the MJ15003/4 devices provided superior bonding of
wires to the chip.
But you knew all that, Phil.
--
Trevor Wilson
www.rageaudio.com.au
Phil Allison
> >
> > "Absolute crap" is code for Trevor doesn't like them.
>
> **Nope. "Absolute crap" is for the low speed, low Voltage rating, low
> linearity and poor thermal cycling ability of the old aluminium cased
> MJ802/MJ4502 transistors. I have a report somewhere, written by RCA
> engineers, tabling the thermal reliabiliyt of aluminium vs. steel cased
TO3
> transistors. Steel cased TO3 devices demonstrate far more than ten times
the
> thermal cycling capability. Likely that is why Motorola changed to steel.
> Moreover, RCA variants of the MJ15003/4 devices provided superior bonding
of
> wires to the chip.
>
> But you knew all that, Phil.
** Like I said, Trevor doesn't like them.
I built a number of power amps using them in the late 70s and they are
all still working fine. My own power amp uses MJ15003/4 types as a
substitute and has slightly higher THD as a result.
I think even NOS would be very hard to find nowadays so the whole issue
is moot anyway. But realise when you buy new MJ802/4502s you are going to be
supplied the substitutes.
Regards, Phil
>
> --
> Trevor Wilson
> www.rageaudio.com.au
>
>
war...@gmail.com
Can anybody help me to know where I can find them ?...or which exactly substitute I can be use and where I can buy?...
Thanks, best regards
