Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: duke of earl on May 08, 2010, 08:19:19 pm
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Wondering what values you guys like on the totem pole stack for a deluxe reverb build.
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Whaddya mean?
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Wondering what values you guys like on the totem pole stack for a deluxe reverb build.
Tone stack?
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I googled "totem pole" and "fender", it seems to mean either the tone stack pots or all the components in the tone stack.
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I like the same as used on the AB763 DR circuit.
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If by "totem pole" you are referring to the series shunted capacitors in the first stage of the power supply, Fender didn't use a totem pole in the DR. Rather, his first filter consisted to two, 16uF caps in parrellel, for a total filter of 32uF. The stock totem pole in the other BF and SF Fenders was two, 70 uF, 350V caps in series to ground, for a total filter of 35uF. The totem pole was necessary in the larger Fenders because the power supply voltage was too high for the use of 450V caps, not an issue in the BFDR.
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Stock values are fine. You may consider using a mid pot instead of a fixed R and/or add a raw control.
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My bad I meant totem pole Filter caps for B+. So the totem pole concept is 2 caps in parallel but if they are in series they are not considered as such.
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Two caps in parallel in the B+? Interesting. The only place I have seen that is in audiophile amps to try and reduce impedance or ESR. Like a 40uF ecap in paralell with a 0.47uF cap.
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So the totem pole concept is 2 caps in parallel but if they are in series they are not considered as such.
I would think just the opposite. Looking at a schematic, you will usually see parallel caps drawn side by side but series filter caps are usually stacked vertically, one on top of the other, totem pole style. I don't recall hearing this term applied to filter caps (although I can see why it may be used) but it was a popular term in some TTL devices' output stage.
Two caps in parallel in the B+? Interesting. The only place I have seen that is in audiophile amps to try and reduce impedance or ESR.
Look at this...
http://www.schematicheaven.com/fenderamps/deluxe_reverb_ab763_schem.pdf
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I like the same as used on the AB763 DR circuit.
likewise... :smiley:
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.
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Only time I've ever heard of totem pole output is for logic gates. The PRR gif all the way to the right.
http://www.asic-world.com/digital/gates5.html
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The TTL stack almost always gets called "totem pole". Oddly the CMOS stack almost never is.
The "Dynaco" stack used to be called "totem-pole".
Later schemes often mixed PNP with NPN and were called "complementary totem-pole", instantly shortened to "complementary". Also that would be a totem pole with one face upside-down. There are upsidedown-faced totem poles but they are not the usual style (it is meant to be rude, but there are easier ways to get rude).
I don't usually see the LA2a plan called "totem pole", though perhaps because this stack has another name (White Cathode Follower).
Maybe I live in the wrong place, but I've never heard it used for the cap-stack or the Fender tone stack. Sorry.
I included the cap-stack because the totem-pole concept DOES fit. Whereas the parallel-cap plan is "not" a totem-pole, as shown on the left.
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Interesting responses! I was referring to the far left diagram of the 2 caps in series with the voltage divider that PRR shows in the GIF. Cool Totem Pole BTW.
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Duke, where did you hear the series caps referred to as 'totem pole'? Got a link?
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Don't remember but I will let you know if I find it. Maybe A Gerald Weber Book?