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In the Tweed Deluxe where would carbon comps benefit the most?

Referencing the schem here
http://www.trinityamps.com/ForumGallery ... 5Mar08.jpg

I would say R7, R8, R13, R14. Anymore or any less?

Also the R16 and R17 are those just part of a RC high pass filter? At first I thought they might be grid leak resistor but then saw they were kind of a low value and they were in front of the grid stopper resistors.

Why on the schematic are R10 and R11 listed as 1W and the layout they are shown as normal 1/2W resistors. I cant see why they would need to be 1W.

Finally what power rating is adequate for the output tubes grid stoppers (the 1K5 ones). I would think 1W.

Thanks...
Chris

The best and most effective place for carbon comp resistors is the combination of:

- where the DC voltage differential across the resistor is the most
- where the AC signal voltage swing is the most
- and where gain is the least, for minimum hiss

IMO R14 best meets all of those criteria, so I would personally only make R14 a carbon comp. Also to maximise the non-linearity, I would use a 1/2W, which is still adequate power-wise.

Everywhere else in a Tweed Deluxe I would use carbon films.

For power tube grid stoppers 1/2W is adequate. However 1W usually fill the space better in a tube amp and produce less noise.

HTH

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Great tones come in small glass jars!

Thanks Phil!

My plan was to use 1W carbon film for all resistors besides the CC's and the 2W oxides in the power section.

Was going to use 1W CC's btw to reduce noise.

As R14 isn't a very sensitive spot for noise, coming right before cathodyne PI which has less than unity gain, I would recommend a 1/2W for more non-linearity.

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Great tones come in small glass jars!

What do you mean more non-linearity?

Carbon comp resistors behave in a non-linear asymmetric way under high voltage conditions, which adds some even harmonic sweetness to an amp's tone. This is explained in www.geofex.com/Article_Folders/carbon_c ... oncomp.htm

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I built my second Deluxe using all metal film (my first was done using what was provided in the kits) When I'm completely done with the second amp I'll let you know how different, and in which way they differ, the amps are.

I've taken way too much time building this second Deluxe

Hi guys, not to beat a dead horse...

I'm starting a Deluxe scratch build (don't ask!) and I've noticed that many of the layout drawings and BOM's here and elsewhere call out a 2W/22k resistor for what would be R21 in the schematic below, next to the 2W/4.7K around the filter cap area. I've noticed that most people seem to use a 1/2 watt carbon comp in this position instead. Is this another one of those "Mojo" places to use a CC resistor and is 1/2 watt adequate for this position?

http://www.trinityamps.com/ForumGallery ... 5Mar08.jpg

Thanks!
Joe G

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Some assembly required,
Brain sold separately...

Joe G

_________________
Some assembly required,
Brain sold separately...

Anything on on the power rails warrants a 2W IMO. That's what we supply too. That feeds the power tubes.

Go for 2W JV

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

Thanks Stephen. I've seen lots of pics like this one in my internet travels...
viewtopic.php?t=817

Five pictures down shows the 22k looking a lot like the 1/2watt carbon comps around it. I want to minimize some noise but don't want to miss some carbon magic in the process or sterilize my build too much

Joe G

_________________
Some assembly required,
Brain sold separately...

That's an old pic to be sure. First kit too but we use 2W now. I guess you could use 2W carbon comp.

It is a voltage dropping resistor before caps so I don't see you loose any Mojo going without a CC resistor there. It only feeds screens on Power tubes but it is in a hi voltage application.

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

The maximum mojo place for carbon comps is the load resistors of the phase invertor or of the final preamp stage.

_________________
Great tones come in small glass jars!