My guess... would be the brown one.
Its in a very easy to get to position, something a good designer would do.
Location: Coventry
Posts: 131
I'm Mick.
My guess... would be the brown one.
Its in a very easy to get to position, something a good designer would do.
My System
John Wood KT88 Amp.
Paradise Phono Stage
Sony TTS-8000 Turntable.
PMAT-1010 MK6 Tonearm.
Ortofon Cadenza Bronze
Sony X555ES Cd Player
Yamaha NS1000m Speakers
Location: London
Posts: 313
I'm David.
30ma sounds very low for an amp with claimed 100watts per channel. It won't do any harm at that level but I'd expect 60ma to get the claimed output
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I’m only going by what the maker told me, he also confirmed what has already been stated that it is indeed the brown resistor that the bias is measured from.
Could you tell me what doubling the bias would do in terms of what I’d hear, from the little I understand it would shorten the valve life, but if it brings a great improvement I could live with that.
My System
John Wood KT88 Amp.
Paradise Phono Stage
Sony TTS-8000 Turntable.
PMAT-1010 MK6 Tonearm.
Ortofon Cadenza Bronze
Sony X555ES Cd Player
Yamaha NS1000m Speakers
Location: London
Posts: 313
I'm David.
The difference you'd hear depends on the amp design, your speakers and other factors. In my own amps I can hear the sound decrease in quality as bias is lowered from the optimum 'hot' spot for example. As for valve life, the Radford STA100 and TT100 run their valves at 60ma and valve life is decent.
But I'd check with John and go with his recommendation and /or ask him what he thinks about backing off the bias a bit. If the setting is in fact 60ma, backing off to 30ma is a huge reduction to around 17 watts dissipation per tube.
It’s the other way round,30 is what he told me to set the bias at. So I guess it would be upping it if anything.at 30 there is absolutely nothing I’m unhappy about, the sound is lovely,as always though there is that “what if” thinking lol
My System
John Wood KT88 Amp.
Paradise Phono Stage
Sony TTS-8000 Turntable.
PMAT-1010 MK6 Tonearm.
Ortofon Cadenza Bronze
Sony X555ES Cd Player
Yamaha NS1000m Speakers
Do what JW said. You'll just end up spending large sums on replacement valves more often.
Location: London
Posts: 313
I'm David.
Ah I see.
My System
John Wood KT88 Amp.
Paradise Phono Stage
Sony TTS-8000 Turntable.
PMAT-1010 MK6 Tonearm.
Ortofon Cadenza Bronze
Sony X555ES Cd Player
Yamaha NS1000m Speakers
I'm struggling to understand why a valve amp that is not self biasing has been set up so it is (seemingly) not easy for an owner to bias it.
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