Pioneer A400 Eco Friendly?...I don't think so! - UK Vintage Radio Repair and Restoration Discussion Forum

reactolite · 20th Dec 2013, 11:19 am

Being a bit of a recycling enthusiast and energy saver I was a bit horrified when on downloading the service manual for my A400 I discover it's power consumption is rated at 520W!! Is this correct? I listen mainly to my tuner through my headphones which are connected to my amp. I can't believe I'm burning so much power. And sometimes, due to such a weak and dismal indicator light, the unit is unintentionally left on for hours at a time.

cmjones01 · 20th Dec 2013, 11:41 am

No, don't worry about it. The rating of 520W is the maximum it could possibly draw from the mains when playing at full power, and even then it would only be for a fraction of a second. It's purely a theoretical figure, only really useful for choosing what rating of fuse to fit. When running just headphones your A400 will only be drawing 10-20W from the mains. You can check this with a simple plug-in power meter.

Chris

Studio263 · 20th Dec 2013, 11:56 am

Pioneer A-400 - the NAD 3020 of the 90s!

These were a budget-priced 2 x 50W (8 ohm) model of the early 90s, quite well thought of but still pretty basic. At normal listening levels the power consumption is neglegible, you could probably listen all day for less than a penny's worth of electricity.

Using headphones means that the output loading is probably around 200 ohms (largely as a result of the resistors inside the amp that drop the output level down) so apart from the bias current in the output stages there is no-where for all that power to go, so it won't be going in in the first place.

Hi-fi ampliifer design has hardly changed since the A-400 came out (and it hadn't changed much in the 10 years before either) so there really is nothing to worry about. If you know your way around these things it may be a good idea to check the soldering around the output transistors and to check / adjust the bias current, these things are both good for durability / sound quality.

reactolite · 20th Dec 2013, 1:46 pm

Thanks guys, now I can listen with more ease knowing I'm not draining the national grid so much as I thought I was. There is another issue concerning this amp, unless I attach a wire to the ground post on the back and bury the other end into the ground attached to an iron rod (luckily through a ground floor window close by) I pick up spurious stations. Is this a fault with the amp or is what I'm doing correct?

20th Dec 2013, 11:19 am	#1
reactolite Retired Dormant Member Join Date: Dec 2013 Location: North Somerset, UK. Posts: 59	Pioneer A400 Eco Friendly?...I don't think so! Being a bit of a recycling enthusiast and energy saver I was a bit horrified when on downloading the service manual for my A400 I discover it's power consumption is rated at 520W!! Is this correct? I listen mainly to my tuner through my headphones which are connected to my amp. I can't believe I'm burning so much power. And sometimes, due to such a weak and dismal indicator light, the unit is unintentionally left on for hours at a time.

20th Dec 2013, 11:41 am	#2
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,677	Re: Pioneer A400 Eco Friendly?...I don't think so! No, don't worry about it. The rating of 520W is the maximum it could possibly draw from the mains when playing at full power, and even then it would only be for a fraction of a second. It's purely a theoretical figure, only really useful for choosing what rating of fuse to fit. When running just headphones your A400 will only be drawing 10-20W from the mains. You can check this with a simple plug-in power meter. Chris __________________ What's going on in the workshop? http://martin-jones.com/

20th Dec 2013, 11:56 am	#3
Studio263 Octode Join Date: Apr 2007 Location: Hampshire, UK. Posts: 1,577	Re: Pioneer A400 Eco Friendly?...I don't think so! Pioneer A-400 - the NAD 3020 of the 90s! These were a budget-priced 2 x 50W (8 ohm) model of the early 90s, quite well thought of but still pretty basic. At normal listening levels the power consumption is neglegible, you could probably listen all day for less than a penny's worth of electricity. Using headphones means that the output loading is probably around 200 ohms (largely as a result of the resistors inside the amp that drop the output level down) so apart from the bias current in the output stages there is no-where for all that power to go, so it won't be going in in the first place. Hi-fi ampliifer design has hardly changed since the A-400 came out (and it hadn't changed much in the 10 years before either) so there really is nothing to worry about. If you know your way around these things it may be a good idea to check the soldering around the output transistors and to check / adjust the bias current, these things are both good for durability / sound quality.

20th Dec 2013, 1:46 pm	#4
reactolite Retired Dormant Member Join Date: Dec 2013 Location: North Somerset, UK. Posts: 59	Re: Pioneer A400 Eco Friendly?...I don't think so! Thanks guys, now I can listen with more ease knowing I'm not draining the national grid so much as I thought I was. There is another issue concerning this amp, unless I attach a wire to the ground post on the back and bury the other end into the ground attached to an iron rod (luckily through a ground floor window close by) I pick up spurious stations. Is this a fault with the amp or is what I'm doing correct?