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Old 10th April 2009, 01:46 PM   #11
pointy is offline pointy  United Kingdom
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i think you would need a resistor in there somewhere just to be safe
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Old 10th April 2009, 03:18 PM   #12
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start with a resistor at the same value as the anode resistor.
then with a multi meter you should be able to trim down so you don't overload the valve.
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Old 10th April 2009, 03:27 PM   #13
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sorry my last post was a load of bull you would need to set it so that you do not over load the anode which ever way it is switched. by having the cap and resistor by pass switching to a resistor by pass. and then adjust the anode resistor to suit.
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Old 10th April 2009, 04:13 PM   #14
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sorry as I said at the start (it may be worth your while waiting for someone else to post on this subject)

but what you will need to do is give the same resistance which ever way the anode by pass is switched

and I am going to have to admit that the way to do it I have not got at hand at the moment

what you will need to do is balance the resistance the same as with just the anode resistor

and then when switched may by using a double pole switch
so you can change from the single resistor to a balanced resistors with the by pass (same resistance)on the throw.

but as I have said it will be best to see what the others say about this
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Old 13th April 2009, 12:35 AM   #15
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this is all i remember of bass boost on a se reel to reel
(without changing the original sound of the amp)

you would replace the anode resistor with the circuit in the picture
(which i hope has come out OK)

then when you place the anode resistor in the red area

you must have the same resistance across everything in the blue area

i believe the lower of the two resistors in the blue area should have the greatest resistance of the two resistors in the blue area

remember to use components that are of the right working volts, watts, etc.....

the switch should be a fast snap over type

this will give a tone boost

BUT BEFORE YOU TRY THIS WAIT FOR SOMEONE WHO IS IN THE KNOW TO HAVE THEIR SAY...........!
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Old 14th April 2009, 12:21 PM   #16
pointy is offline pointy  United Kingdom
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i would try to keep it so the non bypassed resistor in the blue area is at 90% of the total resistance within the blue area.

this is the only boost that i know of that works on a se small amp so that when you throw the switch back you will have the true sound of the original amp.
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Old 14th April 2009, 06:07 PM   #17
m6tt is offline m6tt  United States
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Here's the radiotron designer's handbook on tone controls, more ways to cut/boost in there than you can shake a guitar at:

http://headfonz.rutgers.edu/RDH4/CHAPTR15.PDF
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Old 15th April 2009, 04:51 PM   #18
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if you mean... as in the drawing with the resistor in the red area being the original plate resistor and every thing in the blue area being the same resistance as the plate resistor.

and you will want the resistor at the bottom of the blue area the non by-passed one to be about 90% of the total resistance in the blue area, no less

then you can try out a few non polarized capacitors as long as all the parts are of the working volts needed.

but I would still want to see someone else give this design the thumbs up before trying it out,

as i have not done any work on valve amps in the last 30 years
( i am a bit rusty) ..
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