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Old 23rd July 2011, 01:14 PM   #11
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They do.

But the ear is an interesting instrument, after a while it can 'tune out' certain sounds, ignore them if you will. Whenever I play in a new venue it always takes a while to get used to the room. After a while you start thinking to yourself 'it really doesn't sound as bad as what I though originally'.
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Old 26th July 2011, 04:20 AM   #12
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I have two more spare PCBs for my mods. I will assemble one and attempt the mods on it. But one thing is sure - I am going to remove the protection circuit on these assembled boards as I will use speaker protection circuit.

Gajanan Phadte
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Old 26th July 2011, 05:52 AM   #13
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The foldback current limiting on a Leach is to protect it from shorts and being driven hard into clipping on low impedance loads. A friend can make his produce 'farting' sounds when driving more than 6dB into clipping on a 2Ω load. Other than that, I have never heard the foldback limiter.

If you mean a DC protection relay, that's a different function. I prefer both.
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Old 26th July 2011, 06:49 AM   #14
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Yes, I mean the dethump and dc protection circuit with a relay.

I intend to protect the speaker only and the amp should sound good.
As far as the frontend bias goes, I find that the consensus is that it sounds good.

Can the zener noise be reduced if I make zener from transistors.

Gajanan Phadte
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Old 26th July 2011, 08:38 AM   #15
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No, the reverse BE junction is just as noisy.

Transistors can be used when you need a ~7V zener, you can but a cheap transistor for less than a zener.

Audio Amateur had a noise generator project the amplifier a BE junction noise.

On the other hand, Nelson Pass used the BE junctions with 0.1F in many of his designs.
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Old 26th July 2011, 09:12 AM   #16
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Rapid sell the small Zeners at between 0.70 to 1.59 per hundred.
I can't get transistors that cheaply.
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Old 26th July 2011, 09:28 AM   #17
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Surface mount 2N3904 go for $1.04 per hundred to about $2.16, depends on the vendor and total quantity.

I buy through-hole transistors at $3.00 a hundred.
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Old 26th July 2011, 09:37 AM   #18
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I get my transistors free from discarded boards and I prefer them as they r not fakes. Any damn transistor is mostly a fake here.

Gajanan Phadte
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Old 27th July 2011, 04:39 AM   #19
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Zeners are noisy. What if I replace R13 with 317L and R14 with 337L.

Taking all the care for selection of components around these regulators, shall I have improved the performance.

They will regulate the supply to 40 V.

Gajanan Phadte
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Old 27th July 2011, 04:43 AM   #20
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The zeners will be gone.
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