Anyone heard of SOUND? (SAQ-505)

brett-ballarat · 17th September 2007, 01:10 AM

Hi all,
Just inherited an amplifier - marked as a SOUND SOLIDSTATE STEREO AMPLIFIER.
Model SAQ-505.

I'm still tracing out the circuit - it has 4 * PNP Ge OUTPUT transistors (2SB407)

I believe it to be the same as the SAQ 501 (markings on the main transformer and attached pics)

There are a few trace cuts on the board that make me think it is based on the 501 boards also.

Anyone have any ideas for replacements for the 2SB407? They are all blown short and a nasty whack of DC is curently squatting on the outputs.

Any help appreciated.

<IMAGES OF AMPLIFIER>

dave39 · 25th December 2010, 10:37 AM

I know it is 3 years ago but did you ever find any information, I have just acquired a SOUND SAQ 505 amplifier which was connected to a QUAD 33 pre-amplifier. The previous owner pensioned them off because there was a big thump when the amp was switched on which could suggest a similar fault to what you mentioned with a whack of DC on the output.

Dave

Ian Finch · 25th December 2010, 10:39 PM

Hi Dave
Not many germanium PNP power transistors around now but I notice on a Google search that B&D Enterprises - Electronic Components Distributor have 6 in stock!!! Better get cracking!
BTW, this "Sound" brand may be just a badge job to cover a generic design by a Japanese manufacturer way back in the '60s when brand names were a sensitive issue. The same amp could have had any number of brands applied worldwide. Perhaps the OEM is marked in fine detail somewhere.

Svetolik · 19th July 2011, 02:05 PM

Just picked up the same Sound saq 501 amp.
Lot of hum and distorzion with 2V and 8V DC on the speakers terminal.
There is 40V and 27V voltage on the tween electrolytic and -8V and 24V on the other ones.
Does anybody has schematic?

Bone · 03:46 PM

2SB407

Vceo - 30v
Vcbo - 30v
Vebo - 10
Ic - 7A Max
hFE @ 1.5v Vce & 1A Ic = 80 approx
Power @ 25 C = 30 watts
Ft - 350KHz

Svetolik · 19th July 2011, 04:49 PM

[QUOTE=Bone;2643769]2SB407

Vceo - 30v
Vcbo - 30v
Vebo - 10
Ic - 7A Max
hFE @ 1.5v Vce & 1A Ic = 80 approx
Power @ 25 C = 30 watts

Ft - 350KHz
I think it is not bad at all because it is in the ultrasonic band so the shematics is probably without strong feedback.
There is interstages trafos inside and sounds very good at moments.

Svetolik · 19th July 2011, 06:14 PM

[QUOTE=Bone;2643769]2SB407

Vceo - 30v
Vcbo - 30v
Vebo - 10
Ic - 7A Max
hFE @ 1.5v Vce & 1A Ic = 80 approx
Power @ 25 C = 30 watts

Ft - 350KHz
I think it is not bad at all because it is in the ultrasonic band so the shematics is probably without strong feedback.
There is interstages trafos inside and sounds very good at moments.

Svetolik · 20th July 2011, 02:02 PM

Works!
Replaced electolytic with -8V DC reading and it works and works damn good.
It is a quick death for fancy branded toys...

17th September 2007, 01:10 AM	#1
brett-ballarat diyAudio Member Join Date: Jun 2007	Anyone heard of SOUND? (SAQ-505) Hi all, Just inherited an amplifier - marked as a SOUND SOLIDSTATE STEREO AMPLIFIER. Model SAQ-505. I'm still tracing out the circuit - it has 4 * PNP Ge OUTPUT transistors (2SB407) I believe it to be the same as the SAQ 501 (markings on the main transformer and attached pics) There are a few trace cuts on the board that make me think it is based on the 501 boards also. Anyone have any ideas for replacements for the 2SB407? They are all blown short and a nasty whack of DC is curently squatting on the outputs. Any help appreciated. <IMAGES OF AMPLIFIER> __________________ My amplifier worked until all the smoke leaked out !

25th December 2010, 10:37 AM	#2
dave39 diyAudio Member Join Date: Dec 2010 Location: Canberra	SOUND SAQ 505 I know it is 3 years ago but did you ever find any information, I have just acquired a SOUND SAQ 505 amplifier which was connected to a QUAD 33 pre-amplifier. The previous owner pensioned them off because there was a big thump when the amp was switched on which could suggest a similar fault to what you mentioned with a whack of DC on the output. Dave

25th December 2010, 10:39 PM	#3
Ian Finch diyAudio Member Join Date: Apr 2010 Location: Coffs Harbour, on the east coast	Hi Dave Not many germanium PNP power transistors around now but I notice on a Google search that B&D Enterprises - Electronic Components Distributor have 6 in stock!!! Better get cracking! BTW, this "Sound" brand may be just a badge job to cover a generic design by a Japanese manufacturer way back in the '60s when brand names were a sensitive issue. The same amp could have had any number of brands applied worldwide. Perhaps the OEM is marked in fine detail somewhere. __________________ regards

19th July 2011, 03:39 PM	#5
Bone diyAudio Member Join Date: Jun 2004 Location: Dorset, UK	2SB407 Vceo - 30v Vcbo - 30v Vebo - 10 Ic - 7A Max hFE @ 1.5v Vce & 1A Ic = 80 approx Power @ 25 C = 30 watts Ft - 350KHz Last edited by Bone; 19th July 2011 at 03:46 PM. Reason: left some data off

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19th July 2011, 02:05 PM	#4
Svetolik diyAudio Member Join Date: Dec 2009	Just picked up the same Sound saq 501 amp. Lot of hum and distorzion with 2V and 8V DC on the speakers terminal. There is 40V and 27V voltage on the tween electrolytic and -8V and 24V on the other ones. Does anybody has schematic?

19th July 2011, 04:49 PM	#6
Svetolik diyAudio Member Join Date: Dec 2009	[QUOTE=Bone;2643769]2SB407 Vceo - 30v Vcbo - 30v Vebo - 10 Ic - 7A Max hFE @ 1.5v Vce & 1A Ic = 80 approx Power @ 25 C = 30 watts Ft - 350KHz I think it is not bad at all because it is in the ultrasonic band so the shematics is probably without strong feedback. There is interstages trafos inside and sounds very good at moments.

19th July 2011, 06:14 PM	#7
Svetolik diyAudio Member Join Date: Dec 2009	[QUOTE=Bone;2643769]2SB407 Vceo - 30v Vcbo - 30v Vebo - 10 Ic - 7A Max hFE @ 1.5v Vce & 1A Ic = 80 approx Power @ 25 C = 30 watts Ft - 350KHz I think it is not bad at all because it is in the ultrasonic band so the shematics is probably without strong feedback. There is interstages trafos inside and sounds very good at moments.

20th July 2011, 02:02 PM	#8
Svetolik diyAudio Member Join Date: Dec 2009	Works! Replaced electolytic with -8V DC reading and it works and works damn good. It is a quick death for fancy branded toys...

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