Sick pioneer SA6200

Mike H · Post by **Mike H** » Sat Nov 27, 2010 9:52 pm

So there you are. Where are you?

Ali Tait · Post by **Ali Tait** » Sun Nov 28, 2010 6:44 am

If you have a dac it's worth using the digi out from the Sky box. Quite a bit better than the analogue outs imho.

colin.hepburn · Post by **colin.hepburn** » Tue Dec 07, 2010 8:51 pm

colin.hepburn wrote:Well I Have Just Acquired a second Pioneer SA-6200 well in January I will so thinking I will bi-amp the system using the NAD pre-Amp as I am at the moment with the SA-2600 or maybe a Nelson Pass BI Buffer

So which way to bi- Amp the normal way one amp driving Left/Right bass with the other amp driving the Left/Right top end Or Use The Mono Button And mono Block The Amps placing by the Speaker With sort speaker leads and longer interconnections which way would you think best

Well Got the Second Pioneer SA-6200 today after seven day on the road dont ask

OK Here's the verdict on it
1} Preamp volume control and selector and Switches Nakard
2} Noisy intermittent Transistor in Left Preamp Channel
3} Bad Capacitors and or Transistor Dry Joints in phono Stage
resulting in a Cracking Sound? That follows the bass notes
However this is not a problem As the Pre-Amp is the weakest link in the amp anyway and will be pulled out
As I only want to use the power Amp which Works Fine But will be Re Capping And silver wired and then Re Cased
This will be done to both the amps and they will be bi-amped in to the system
However as we are unsure what the idle Current should be set at for both these amp I checked this amp to find it was much higher than I expect
61mV/0.5R=122mA

Heatsink is warm but i still can leave my hand on it

Mike H · Post by **Mike H** » Wed Dec 08, 2010 2:21 am

Are you sure you're not reading millivolts as milliamps again?

If it's actually 61mV then it's only 30.5mA.

Post by **Nick** » Wed Dec 08, 2010 8:36 am

Mike H wrote:Are you sure you're not reading millivolts as milliamps again?

If it's actually 61mV then it's only 30.5mA.

Are you sure about that

61/0.5 = 61*2 = 122

colin.hepburn · Post by **colin.hepburn** » Wed Dec 08, 2010 8:56 am

Nick wrote:
Mike H wrote:Are you sure you're not reading millivolts as milliamps again?

If it's actually 61mV then it's only 30.5mA.

Are you sure about that

61/0.5 = 61*2 = 122

Yep thats what I am thinking as well nick
Mikes : 61mV*0.5R=30.5mA

Mine: 61mV/0.5R=122mA

Mike H · Post by **Mike H** » Wed Dec 08, 2010 3:57 pm

OK so I pressed the wrong key.

It's too much then.

Possibly.

colin.hepburn · Post by **colin.hepburn** » Fri Dec 10, 2010 1:50 pm

Mike H wrote:OK so I pressed the wrong key.

It's too much then.

Possibly.

No Worries mike pressed the wrong button AH

122 mA to much then I was hoping I would be able to get the correct current reading of this amp hopping that no one had be inside it But as someone has changed the mains lead inside so can't say if they have tampered with the current or not
This amp has been running continually @ this 122mA for the last three day mostly the AV system its warm but you can keep your hand on the headshink ok and it seems stably and sound is good to

Mike H · Post by **Mike H** » Fri Dec 10, 2010 1:55 pm

So at least that proves it's possible. Which is useful to know.

Could be just because the presets have gone "dirty"

Were you going to replace them on the other one? Or did you?

colin.hepburn · Post by **colin.hepburn** » Fri Dec 10, 2010 2:07 pm

Mike H wrote:So at least that proves it's possible. Which is useful to know.

Could be just because the presets have gone "dirty"

Were you going to replace them on the other one? Or did you?

No not yet But it is the plan to replace the Pre-sets when I recap at the same time But I Did Clean and turned the back and frothy a few time on the other amp and reset to run about 80mA and had no problems with it and it runs only just warm to the touch

Mike H · Post by **Mike H** » Fri Dec 10, 2010 2:46 pm

OK then!

colin.hepburn · Post by **colin.hepburn** » Fri Dec 10, 2010 10:02 pm

Mike H wrote:OK then!

OK so running each amp @ 80mA should be OK then
40mV/0.5R=80mA
I always thought you added up the total Current of all the amp parts i.e. preamp phono power amp to set the idle up
I find this idle current thing a tad confusing Example My NAD 352 taking from the manual
300 ohms for 5-6.5mV reading on meter
.6.5mV/300R=21mA seems very low for an 80 WATT Amp when you consider the pioneer is only a 22 watter

Post by **Nick** » Sat Dec 11, 2010 12:30 am

It depends on how much class A its designed for, higher idle current = more class A.

colin.hepburn · Post by **colin.hepburn** » Sat Dec 11, 2010 11:23 am

Nick wrote:It depends on how much class A its designed for, higher idle current = more class A.

Yep that's what I figured the higher idle Current is the longer the amp stays in Class A But in the Case of the pioneers here the idle current is not stated in the schematic so what sets the limit you can increase the current too also see this link http://www.tnt-audio.com/clinica/bias_e.html

Mike H · Post by **Mike H** » Sat Dec 11, 2010 12:35 pm

Yep that's why I always try to use sealed enclosed presets, including multi-turn where most appropriate.

I guess the DC bias could be as much as it will stand heat wise.

About 25 years ago I'd got meself a new Pioneer 100W per channel amp, had a big heatsink in it that was always hot even at low power / idle. From which I deduced the bias was on the high side on purpose for more class A.

audio-talk

Sick pioneer SA6200

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