old device specs

$orabji! · 1st January 2006, 10:26 AM

Hi,

I'm restoring an old early 70's one-of-a-kind amp made by a talented friend (now deceased) and am looking for the specs for these devices.

Motorola

SJ3679
SJ3678
SJ3681
SJ3680

Knowing the guy who built it, the devices are probably hand selected for CEv. Likely also selected as full SOA devices in that I*V=P where P is a constant up to the current limit. (that's how this fellow built his personal stuff) But I know not P or I. It uses 6 of the SJ3679/8 devices per channel w/ a 40V regulated supply. Runs in class A for 8 ohm load ~ 1.5A bias per side. The other devices are the drivers.

Just trying to get a better idea of what I'm working with. The amp works just fine, (better than many 'modern' amps - i.e. clean power bandwidth to over 100K, even with these old devices) and not I'm planning on replacing these devices unless it's necessary. I've been unable to find these as they are so old and my library doesn't go back that far.

This is a very advanced amp for its time.

Thanks for any info,

~ Sorabji

Netlist · 1st January 2006, 10:37 AM

I have no indication of the existence of these devices.
Not by number and not by Motorola Xref.
2SC36XX is possible but these would be Sanken or for the 2SC3681, Sanyo.
Could you provide a picture?

/Hugo

Onra · 1st January 2006, 11:21 AM

Hi,
i looked up an older ECG-list and found ECG-replacements for three of them:
SJ3678 is NPN replaced by ECG130 (maybe a 2N3055), TO3,
SJ3679 is PNP replaced by ECG219 (complementary type of ECG130), TO3;

SJ3680 is NPN replaced by ECG175 high voltage audio in case TO66
SJ3681 not found in this list, but ECG´s complementary type to ECG175 is ECG 38 in same case and voltage range.
Onra

peranders · 1st January 2006, 11:53 AM

$orabji!, if you by any chance have a schematic I'm pretty sure that the gathered expertize here can find suitable replacements.

Netlist · 1st January 2006, 12:44 PM

Onra made me dig a little deeper.
So, for the SJ3678 we have:
VCB:100
VCE:60
VEB:7
IC: 15
PD: 115
ft: 800Khz
Hfe: 40

SJ3679:
VCB:100
VCE:70
VEB:7
IC: 15
PD: 150
ft: 4Mhz min.
Hfe: 20 min.

SJ3680:
VCB:500
VCE:300
VEB: 6
IC: 3
PD: 40
ft: 10Mhz
Hfe: 50 typ

ECG38 (no SJ3681 here as well)
VCB:400
VCE:350
VEB:6
IC: 2 cont. 5 peak
PD: 35
ft: 20Mhz
Hfe: 50typ

/Hugo

$orabji! · 2nd January 2006, 01:19 AM

Many thanks!

anatech · 2nd January 2006, 03:24 AM

Hi $orabji!,
Those do sound like old Motorola part numbers for "factory numbered" devices. Motorola will have no specs on these numbers. They are like a state secret.

Be very cautious of subs listed by ECG or NTE. Do not cross in and out of these manuals.

Hugo,
Where did you find listings for those? Just curious. These numbers remind me of older Marantz part numbers.

-Chris

Netlist · 2nd January 2006, 08:35 AM

Data comes from an old '89 ECG catalogue.
Indeed, one can only hope the info is reliable.
http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm already lists different specs for some devices parameters when looking at the datasheets.

/Hugo

djk · 2nd January 2006, 10:53 AM

Chris is right, they look like house numbers used by Marantz.

The outputs are the 2N5631(NPN), and the 2N6031(PNP).

The drivers are the 2N3584(NPN) and 2N6421(PNP)

1st January 2006, 10:26 AM	#1
$orabji! diyAudio Member Join Date: Sep 2003 Location: Fort Bragg CA	old device specs Hi, I'm restoring an old early 70's one-of-a-kind amp made by a talented friend (now deceased) and am looking for the specs for these devices. Motorola SJ3679 SJ3678 SJ3681 SJ3680 Knowing the guy who built it, the devices are probably hand selected for CEv. Likely also selected as full SOA devices in that I*V=P where P is a constant up to the current limit. (that's how this fellow built his personal stuff) But I know not P or I. It uses 6 of the SJ3679/8 devices per channel w/ a 40V regulated supply. Runs in class A for 8 ohm load ~ 1.5A bias per side. The other devices are the drivers. Just trying to get a better idea of what I'm working with. The amp works just fine, (better than many 'modern' amps - i.e. clean power bandwidth to over 100K, even with these old devices) and not I'm planning on replacing these devices unless it's necessary. I've been unable to find these as they are so old and my library doesn't go back that far. This is a very advanced amp for its time. Thanks for any info, ~ Sorabji

1st January 2006, 11:53 AM	#4
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	$orabji!, if you by any chance have a schematic I'm pretty sure that the gathered expertize here can find suitable replacements. __________________ /Per-Anders (my first name) or P-A as my friends call me Tube Buffered Gainclone in work \|Thread

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1st January 2006, 10:37 AM	#2
Netlist diyAudio Moderator Emeritus Join Date: Jan 2003	I have no indication of the existence of these devices. Not by number and not by Motorola Xref. 2SC36XX is possible but these would be Sanken or for the 2SC3681, Sanyo. Could you provide a picture? /Hugo

1st January 2006, 11:21 AM	#3
Onra diyAudio Member Join Date: Jul 2005 Location: near Frankfurt/M	Hi, i looked up an older ECG-list and found ECG-replacements for three of them: SJ3678 is NPN replaced by ECG130 (maybe a 2N3055), TO3, SJ3679 is PNP replaced by ECG219 (complementary type of ECG130), TO3; SJ3680 is NPN replaced by ECG175 high voltage audio in case TO66 SJ3681 not found in this list, but ECG´s complementary type to ECG175 is ECG 38 in same case and voltage range. Onra

1st January 2006, 12:44 PM	#5
Netlist diyAudio Moderator Emeritus Join Date: Jan 2003	Onra made me dig a little deeper. So, for the SJ3678 we have: VCB:100 VCE:60 VEB:7 IC: 15 PD: 115 ft: 800Khz Hfe: 40 SJ3679: VCB:100 VCE:70 VEB:7 IC: 15 PD: 150 ft: 4Mhz min. Hfe: 20 min. SJ3680: VCB:500 VCE:300 VEB: 6 IC: 3 PD: 40 ft: 10Mhz Hfe: 50 typ ECG38 (no SJ3681 here as well) VCB:400 VCE:350 VEB:6 IC: 2 cont. 5 peak PD: 35 ft: 20Mhz Hfe: 50typ /Hugo

2nd January 2006, 01:19 AM	#6
$orabji! diyAudio Member Join Date: Sep 2003 Location: Fort Bragg CA	Many thanks!

2nd January 2006, 03:24 AM	#7
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi $orabji!, Those do sound like old Motorola part numbers for "factory numbered" devices. Motorola will have no specs on these numbers. They are like a state secret. Be very cautious of subs listed by ECG or NTE. Do not cross in and out of these manuals. Hugo, Where did you find listings for those? Just curious. These numbers remind me of older Marantz part numbers. -Chris

2nd January 2006, 08:35 AM	#8
Netlist diyAudio Moderator Emeritus Join Date: Jan 2003	Data comes from an old '89 ECG catalogue. Indeed, one can only hope the info is reliable. http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm already lists different specs for some devices parameters when looking at the datasheets. /Hugo

2nd January 2006, 10:53 AM	#9
djk diyAudio Member Join Date: Feb 2001 Location: USA	Chris is right, they look like house numbers used by Marantz. The outputs are the 2N5631(NPN), and the 2N6031(PNP). The drivers are the 2N3584(NPN) and 2N6421(PNP)