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Hey.
I've almost finished a home-brew version of the TC-15, and I need some technical knowledge regarding the option of switching between the 1k5 resistor and the choke. I have both in my amp, and I like the difference they give, even though it's subtle.
The problem is this: I installed a nice big expensive on-off-on switch to use as both a standby, and a switch between choke and resistor. But then I got to reading on Merlin Blencoves site about standby switches.... specifically it seems it's a bit bad to have a standby switch directly before the choke. I presume I could get around this, by wiring up the switch before the first filter cap, and then have a 150k/2W resistor across the switch to the choke. I think this would help avoiding spikes in the choke, when it's switched out. However, this would also mean that I would have the 150k + choke in parallel with the 1k5 resistor, when I switch that in.... and I'm not sure what effect this would have.....????
Any good advice???

Yes, put the standby before the first filter cap, the 1K5 &/or the choke. I.e right after the rectifier.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

well, the problem was to have the same switch do both.
But I think a dpdt could do it in a way that just shorts out either the choke or the 1k5 resistor.
I've attached a schematic - let me know if it seems alright.

Regards.
Anders

The switching of the choke/resistor would work. The standby is in the right place. We don't use a resistor on standby like you plan to though.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

The connection between the poles on sw1a makes the switch irrelevant. Either position gets you the same circuit.

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Must be an error (the drawing equivalent of a typo).

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Go Buckeyes!

arjepsen wants to use one switch to select whether the choke or the 1k5 resistor is in series with the rectifier and also switch the amp in and out of standby. It's a dpdt switch with a center off position. The amp would be in standby in the center position. In the other two positions the amp would run with either the choke or the 1k5 resistor in series with the rectifier.

The poles on the b section either short out the 1k5 resistor or the choke, effectively placing one or the other in series with the rectifier.

Meanwhile the poles on the a section both have to do the same thing which is to connect the rectifier to the rest of the power supply. But in the center position there will be no connection and the amp will be in standby.

arjepsen, your circuit is will work and it's a good efficient way to do the switching. Stephen says you don't need the 150k resistor in standby, Merlin says you do. You'll have to decide which way works best.

Ah....I wasn't visualizing the null position on the switch. Thanks for the correction & sorry to confuse the issue.

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It's not necessary to function, and seldom used but a mod to protect components if you want to and it wont hurt to be in there. Be aware that you wont have the tubes off (muted) with that stand by design tho. Use a 2 watt resistor 47K to 100K

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Yes, the idea with the 150k is to protect the choke.
I built it, and though i havent tested it extensively, it seems to work quite Well. I get no Sound when in the middle position.
I still need to get the head cabinet done for this amp, but i Will probably post pics when its done. I did a ptp layout instead of the board-design.