Newborn Express/ dual biasing for the power tubes?

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Decko
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Newborn Express/ dual biasing for the power tubes?

Post by Decko »

Hi All,

I finished my first Express build! I decided to follow closely the "no named" wreck pictures as a basis for my build. I believe it is a more current revision of the Express. You will notice my lead dress and boards match this layout. The "Worley build guide" was useful. I will make one modification to this build by installing a second bias resistor to the power supply board. It will be enable me to bias the power tubes independently. Then I can use "unmatched" power tubes. The chassis and irons are from Allyn. I used Pacific transformers because Glen has those on "Annie" and his tone is what attracted me to these amps. The trannies are "spec".

Most of the caps are Mallory. Pots are Alpha with the exception of the presence pot which is a Claristat from Allyn.

The preamp tubes are RCA 12ax7. The power tubes are Siemens EL34. I am not sure what year or type of EL34's.

How do it sound? Awesome! Responsive complex harmonics! Zero oscillation. So I guess the lead dress on the "no name" express is good. It is a completely new experience in guitar playing. I will need to get the right speakers. I think I wil go with Scumbucks.

Thanks to the community for all your help, experience and knowledge. I have already started procuring parts for my next build. The "Rocket!"
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pureoldsound
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Re: Newborn Express/ dual biasing for the power tubes?

Post by pureoldsound »

Very nice...... :D
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drhulsey
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Re: Newborn Express/ dual biasing for the power tubes?

Post by drhulsey »

Decko wrote: ... It is a completely new experience in guitar playing...
Yeah :!: And ain't it swe-e-e-e-t 8)
Very nice job :!:
Tim

In case the NSA is listening, KMA!
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geetarpicker
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Re: Newborn Express/ dual biasing for the power tubes?

Post by geetarpicker »

Looks nice! The attention to detail on the pot area lead dress is impressive.

You will probably like the Scumback M75s with it. I have these for my "gigging" cabs though I do run some felt in front of the speakers to tame just a tad more of the top off them.
strato17
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Re: Newborn Express/ dual biasing for the power tubes?

Post by strato17 »

geetarpicker wrote:Looks nice! The attention to detail on the pot area lead dress is impressive.

You will probably like the Scumback M75s with it. I have these for my "gigging" cabs though I do run some felt in front of the speakers to tame just a tad more of the top off them.
I agree 100%. A very nice, clean, accurate build. I also agree that you would love the scumback M75's. I got two of the 65 watters in a 2x12, and they sound great! I also put some felt in front of the speakers, and It does aid in the top end.
Decko
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Location: California

Attenuator/ Scumbucks cabinet layout

Post by Decko »

Glen, Strato,

This express is loud! I am thinking of using an airbrake so that I can overdrive the tubes to get that distortion. Do any of you guys use them? Are they harmful to the amp?

How is your cab set up?
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Allynmey
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Re: Newborn Express/ dual biasing for the power tubes?

Post by Allynmey »

Congrats on the build! It looks great!
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Bob-I
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Re: Attenuator/ Scumbucks cabinet layout

Post by Bob-I »

Decko wrote:Glen, Strato,

This express is loud! I am thinking of using an airbrake so that I can overdrive the tubes to get that distortion. Do any of you guys use them? Are they harmful to the amp?

How is your cab set up?

I wrecked my Bassman, ok modded a Bassman to an Express. It has 2 volumes, loud and Cops at the front door.

I've compared a PPIMV to an airbrake and there's no question, the airbrake is the way to go. 2 airbrakes are better as you can run them each with less attenuation and get the same volume drop. It seems to be less buzzy if you only drop one or 2 notches on the airbrake.

Is it hard on the amp? I'm not sure. I'd bet the tube life will be lower, but I don't think it'll damage anything else.
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