Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: chocopower on April 12, 2010, 08:39:54 am
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hi,
I´m working in a EF86-12AX7-EL34 amp.
i tried try the DRz tonestack just after the EF86 without good result. Now i installed a 5E3 tonestack and seems to work a lot better.
Serching the forum i found two diferent ways to draw the 5E3 tonestack:
in fact this is a 5F2-A
(http://www.el34world.com/Forum/index.php?action=dlattach;topic=6379.0;attach=7968;image)
and this is the tipical 5E3.
(http://www.el34world.com/Forum/index.php?action=dlattach;topic=6379.0;attach=7959;image)
values are the same, but the way they are positioned is diferent.
What diferents in sound could i wait using one or other method.
thanks in advance.
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I don't think you will hear a difference in sound but they both will interact with the volume pot in a different way.
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I thougt the same... I,m gonna try both ways. Empirical is the best way to learn
thanks!
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I always saw those two as being a bit different!
This has been described in detail by hotblueplates here in the forum in an old post, but the second volume control on the 5E3 really changes the low mid response of the amp.
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"values are the same, but the way they are positioned is diferent.
What diferents in sound could i wait using one or other method."
They are electrically the same, you shouldn't hear any difference between them.
If you don't need a tone control, don't install one for your design or put it AFTER the 12ax7 (I have no idea what you're doing). The less load after the EF86 the better performance you'll get.
*Guys, forget about the 2nd set of inputs of the 5E3, it's a moot point as he's not using that design w/ his amp.
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I´m still working in the schematic, but simplifying is:
Imput---(EF86)---(rotary swicht with coupling caps)---(5E3 tonestack)---(12AX7 cathodyne PI)--(2xEL34 with U.L. output transformer).
No NFB loop.
The initial idea is in this topic, but the treble/bass tonestack eat too much signal.
http://www.el34world.com/Forum/index.php?topic=8349.0 (http://www.el34world.com/Forum/index.php?topic=8349.0)
jojokeo "If you don't need a tone control, don't install one"
Mmmmmmm....Maybe i avoid the tone control and install a cut control after the P.I. could be a good idea. Most of the times i need dial the tone pot on max to get a razonable highs level.
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I´m still working in the schematic, but simplifying is:
Imput---(EF86)---(rotary swicht with coupling caps)---(5E3 tonestack)---(12AX7 cathodyne PI)--(2xEL34 with U.L. output transformer).
No NFB loop.
The initial idea is in this topic, but the treble/bass tonestack eat too much signal.
http://www.el34world.com/Forum/index.php?topic=8349.0 (http://www.el34world.com/Forum/index.php?topic=8349.0)
jojokeo "If you don't need a tone control, don't install one"
Mmmmmmm....Maybe i avoid the tone control and install a cut control after the P.I. could be a good idea. Most of the times i need dial the tone pot on max to get a razonable highs level.
Sounds like it'll play & sound really good as simpler is better & it doesn't get much simpler than that! I like the idea of a tone cut much much better than the standard tone control. Couple that and the rotary tone caps (& EL34's) and you'll have a sweet sounding amp there! The pentode's hi Z output gets loaded down too easily and I'm w/ you on keeping/maintaining the highs as much as possible (w/in reason). The cut control will take care of that & don't forget that you have tone controls on your guitar too. These are more than enough to cut any treble. You actually have the option of of the concertina or LT pair if you wanted to use it?
You also might consider having a lot of fun w/ that pentode and all of the mode, gain, & bypassing options available.
Good luck!
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Continious in the original topic
http://www.el34world.com/Forum/index.php?topic=8349.0 (http://www.el34world.com/Forum/index.php?topic=8349.0)