Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: stingray_65 on February 06, 2012, 12:34:36 pm

Title: "dual rectifier"
Post by: stingray_65 on February 06, 2012, 12:34:36 pm: I've been putzin around the WWW again.

I'm seeing a few references to "dual rectifier mods" and I see Mesa Boogie has a dual rectifier amp.

What's that about?

How does 2 recto's influence the tone or voicing of an amp?

Is it just to compensate for high losses when using a 5U4?

Ray
Title: Re: "dual rectifier"
Post by: John on February 06, 2012, 12:48:14 pm: "Dual Rectifier" sounds cool, and you know us geetar players ain't too smart. :laugh:
Title: Re: "dual rectifier"
Post by: kagliostro on February 06, 2012, 01:23:12 pm: There are two different implementation of the rectifier circuit in the Dual Rectifier

As far as I can know, don't use the first schematic, it is prone to tube failure

About tone change

changing from Tube rectifier to SS rectifier is something like the opposite side on using a VVR

VVR gives early distortion when you turn to low voltage the opposite the SS rectifier respect Tube, also if you don't use a SAG resistor you can imagine the effect

Kagliostro
Title: Re: "dual rectifier"
Post by: stingray_65 on February 06, 2012, 01:30:01 pm: OH!

LOL I see now, either solid state or hollow state!

nothing to with 2 recto tubes!

got it!
Title: Re: "dual rectifier"
Post by: kagliostro on February 06, 2012, 01:42:28 pm: There is one Mesa schematic that is prone to give confusion

The Blue Angel, SS and Tube at the same time, but different circuits are connected to it

Kagliostro
Title: Re: "dual rectifier"
Post by: sluckey on February 06, 2012, 01:52:54 pm: "The term Dual Rectifier originally referred to the two options available to rectify the high voltage current being supplied to the amplifier. However, lesser-informed players assumed it referred to the dual 5U4 tubes in the amplifier"

Yes, it refers to tube and ss rectifiers. However, many of Mesa's dual rectifier amps used 4 big output tubes and one 5U4 can't deliver enough juice for 4 big output tubes. So, you have to run parallel rectifier tubes, or flip a switch and run ss diodes.

I had an old Wurlitzer jukebox amp that ran four 6L6s and it had parallel 5U4s too. I converted it to a Twin Reverb/Bassman amp. You might say it was the original "dual rectifier" guitar amp! :icon_biggrin:

http://home.comcast.net/~seluckey/amps/misc/76_Amp_Project.pdf (http://home.comcast.net/~seluckey/amps/misc/76_Amp_Project.pdf)
Title: Re: "dual rectifier"
Post by: jjackson7 on February 06, 2012, 04:05:08 pm: Quote from: sluckey on February 06, 2012, 01:52:54 pm
"The term Dual Rectifier originally referred to the two options available to rectify the high voltage current being supplied to the amplifier. However, lesser-informed players assumed it referred to the dual 5U4 tubes in the amplifier"

Triple Rec?
Title: Re: "dual rectifier"
Post by: Dave on February 06, 2012, 07:53:27 pm: Quote from: jjackson7 on February 06, 2012, 04:05:08 pm

Triple Rec?

Who's up for a little hair splitting?

Dave
Title: Re: "dual rectifier"
Post by: PRR on February 06, 2012, 11:52:33 pm: Dual rectifier is obviously twice as good.

I had a projector arc-lamp power supply with SIX rectifiers. Imagine how good that would sound !! !! !! If it only had audio input/output.....
Title: Re: "dual rectifier"
Post by: chuggy on February 07, 2012, 05:38:57 pm: Fender narrow panel tweed Twin (5E8A?) had dual 5U4 rectos.
Title: Re: "dual rectifier"
Post by: Willabe on February 07, 2012, 06:29:07 pm: Quote from: kagliostro on February 06, 2012, 01:42:28 pm
The Blue Angel, SS and Tube at the same time, but different circuits are connected to it.

SS to pre amp tubes, Tube rec. to power amp. I think it would be worth checking out. Might sound good to some players?

Brad :think1:
Title: Re: "dual rectifier"
Post by: sluckey on February 07, 2012, 06:38:26 pm: Marketing gimmick???
Title: Re: "dual rectifier"
Post by: Willabe on February 07, 2012, 06:49:35 pm: Quote from: sluckey on February 07, 2012, 06:38:26 pm
Marketing gimmick???

Sure but you might be able to keep the plate voltage higher on the pre amp tubes and let the power tubes still sag and/or at a lower plate voltage on the power tubes than it would take to have the same (higher) plate voltage on the pre tubes down the PSU line?

Brad :dontknow:
Title: Re: "dual rectifier"
Post by: John on February 07, 2012, 08:53:03 pm: Quote from: sluckey on February 07, 2012, 06:38:26 pm
Marketing gimmick???

Never!!!
Title: Re: "dual rectifier"
Post by: RicharD on February 07, 2012, 09:54:10 pm: I have a friend with a Fender something that is switchable between tube and ss rectification. He says it eats tubes when using the ss recto. I haven't been inside of it but I'm assuming there's roughly 50 more volts when rectifying using SS. My guess is the amp is biased bleeding edge when running SS and prolly a little cold with the 5U4GB. I'm sorry but I'm really believing more and more in fewer knobs and switches = better amp.
Title: Re: "dual rectifier"
Post by: kagliostro on February 08, 2012, 03:48:15 am: Quote
He says it eats tubes when using the ss recto.

I would like to see the adopted schematic

this schematic is prone to eat tubes

(http://www.el34world.com/Forum/index.php?action=dlattach;topic=13173.0;attach=28290;image)

this should not do it

(http://www.el34world.com/Forum/index.php?action=dlattach;topic=13173.0;attach=28302;image)

Kagliostro
Title: Re: "dual rectifier"
Post by: Jack1962 on February 08, 2012, 09:30:56 am: I have worked on a few Mesa Dual Recto's , myself I prefer them over a Marshall any day , and sorry guys but they just blow a Fender out of the water lol . The Solid State/ Tube recto switch just check it out you"ll see what it does , tone is tighter with the solid state recto , more sag with the tube.

NO GIMMICK , THE REAL DEAL :laugh: