Hi,
The A6-A model it is the name of Japanese model, for Europa the name for the same model, except power supply, is A760II and A760 it is the name for A6 model. Between A6-A and A6 (or european names A760II and A760) there are a lot of diferences and the schematics are quite diferent.
I ask you again if somebody have the schematic for Yamaha A6-A or european version A760II.
Thank you
The A6-A model it is the name of Japanese model, for Europa the name for the same model, except power supply, is A760II and A760 it is the name for A6 model. Between A6-A and A6 (or european names A760II and A760) there are a lot of diferences and the schematics are quite diferent.
I ask you again if somebody have the schematic for Yamaha A6-A or european version A760II.
Thank you
Here you can find a lot of free service manuals
Yamaha manuals, schematics and brochures - Hifi Manuals
Yamaha manuals, schematics and brochures - Hifi Manuals
I can get a service manual for the A760 - but no luck for an A6 - still looking for a manual on the 760 II
But here is some important safety information from Yamaha about that series of amps. Safety Information Yamaha amplifiers (1980-1982) - Yamaha - Other European Countries
But here is some important safety information from Yamaha about that series of amps. Safety Information Yamaha amplifiers (1980-1982) - Yamaha - Other European Countries
Hi,
Thanks for replay.
I have the schematic for A760, A960, A960II and A1060, some M series and B6.
I think that the only schematic that I do not have is for A6-A (european A760II). This model I have at home.
I already made the transformer at a local supplier but I do not know the values of voltage and I think that I made to high voltage (original transformer was shorted). Now it is working beautiful but some stages from final amplifier work to hot (some current source and voltage suppliers for input stages I think).
I want to update the schematic to increase the efficiency and to reduce the working temperature.
Thanks for replay.
I have the schematic for A760, A960, A960II and A1060, some M series and B6.
I think that the only schematic that I do not have is for A6-A (european A760II). This model I have at home.
I already made the transformer at a local supplier but I do not know the values of voltage and I think that I made to high voltage (original transformer was shorted). Now it is working beautiful but some stages from final amplifier work to hot (some current source and voltage suppliers for input stages I think).
I want to update the schematic to increase the efficiency and to reduce the working temperature.
OK, I know this but what is the values of voltage after bridge for this version?
The output power it is not the same.
On output board I have many components that are working to hot, atleast for my taste.
I want to use a liniar regulators powered from transformer low voltage to decrease the power disipation inside of amplifier.
The output level that I use at home do not warm the heatspreader, the only heating of amplifier is from other sources.
BDW I disconected the Xpower regulator and now the transformer are dirrectly connected to power line and on capacitors the voltage it is ±~56V.
I think that this voltage it is to high. To decrease the voltage I can modify the Xpower module (the original module it is for 100Vac) to work at 230Vac and I can set the voltage from it. The problem is that I do not know the correct values.
The output power it is not the same.
On output board I have many components that are working to hot, atleast for my taste.
I want to use a liniar regulators powered from transformer low voltage to decrease the power disipation inside of amplifier.
The output level that I use at home do not warm the heatspreader, the only heating of amplifier is from other sources.
BDW I disconected the Xpower regulator and now the transformer are dirrectly connected to power line and on capacitors the voltage it is ±~56V.
I think that this voltage it is to high. To decrease the voltage I can modify the Xpower module (the original module it is for 100Vac) to work at 230Vac and I can set the voltage from it. The problem is that I do not know the correct values.
Hii djk,
Sorry but I'm sure that 40V it is to less.
The amplifier specification are 100W/8Ω or 150W/4Ω with 0.003 distorsion. For this power you need more than 40V.
Link to specification: Yamaha A-6a | Hifi-Wiki.de
or: Google Translate
I use it for aroud 1 year now in this condition. The power supply is not with the original transformer and Xpower bypassed. I made at a local supllier a new transformer because I have the Japanese version (100Vac) and more then that the original transformer was shorted. I do not used Xpower because it is for 100Vac and need to be changed.
The model A760 has supply line stabilized to ±47V and the specification are 80W/8Ω, soo I need more than 47V, maybe around 50V
Sorry but I'm sure that 40V it is to less.
The amplifier specification are 100W/8Ω or 150W/4Ω with 0.003 distorsion. For this power you need more than 40V.
Link to specification: Yamaha A-6a | Hifi-Wiki.de
or: Google Translate
I use it for aroud 1 year now in this condition. The power supply is not with the original transformer and Xpower bypassed. I made at a local supllier a new transformer because I have the Japanese version (100Vac) and more then that the original transformer was shorted. I do not used Xpower because it is for 100Vac and need to be changed.
The model A760 has supply line stabilized to ±47V and the specification are 80W/8Ω, soo I need more than 47V, maybe around 50V
"For this power you need more than 40V. "
100W/8Ω is 40V peak.
The X design is a regulated power supply, the amplifier has 0dB of headroom because of this.
A 40V unregulated supply is connected in parallel with the current regulated 40V regulated supply, that is the principle of the X design.
I was an authorized Yamaha service facility back then. I built a subwoofer amplifier using one of the X power supply ICs, and a take-out transformer (had a bit of a mechanical buzz) replaced for a customer. A non-Yamaha amplifier kit was constructed and worked quite well for a number of years.
100W/8Ω is 40V peak.
The X design is a regulated power supply, the amplifier has 0dB of headroom because of this.
A 40V unregulated supply is connected in parallel with the current regulated 40V regulated supply, that is the principle of the X design.
I was an authorized Yamaha service facility back then. I built a subwoofer amplifier using one of the X power supply ICs, and a take-out transformer (had a bit of a mechanical buzz) replaced for a customer. A non-Yamaha amplifier kit was constructed and worked quite well for a number of years.
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