Tweed Twin 5E8-A Finished Build

Diablo · 09-10-2009, 02:52 AM

Here's a link to some photos of my finished build. It started as a Ted Weber kit and I added the following mods:

Vari-watt from Skipz-circuits
1K - 3 Watt screen resistors
1.5K - 1/2 watt grid stoppers on V1 and V2
Safety diodes (1N5408) on the rectifier
Single RCA 5U4GB rectifier
EH 12AY7 tubes in V1, V2, and V3
Shugaung 12AX7 in V4
RCA 7027A for the PA (biased at 45mA and 434 volts)
22 mfd/ 500 volt cap for first filter
Heyboer Multitap OT # 18343

Atlas Amps 5E8A Tweed Twin with Vari-watt - Album - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting

stingray_65 · 09-10-2009, 01:08 PM

GR8 job!

layout is nice and neat.

how does is sound??

tubeswell · 09-10-2009, 07:47 PM

Very tidy - I'm keen to hear how the variwatt affects things (when you are ready)

Diablo · 09-10-2009, 08:52 PM

Thanks gentlemen. There were no problems with the build, and I didn't have to chase any strange hums or noises, so the ground scheme must be OK. I've never played or heard a 5E8A before this one, so it's kind of hard for me to give a critical comparison. I tried to find the 57 Tweed Twin RI at the local guitar center, but they don't have one in stock for me to play - but they'd be willing to order one for me.....

It was funny, they'd never heard of a Tweed Twin before I mentioned it and told them it comes from the Fender Custom Shop.

Anyway, if I compare it to my 5F6A, the amp is more midrangey and at the same time very sensitive on the treble control. It also breaks up earlier with a more singing distortion. The Variwatt does work as described. I can adjust the plate voltage down from 434 volts to 12 volts, and the bias tracks along by itself. I can crank in huge overdrive when the VW plate voltage is reduced and sound like Led Zep, but I find the most use in it just reducing the plate voltage a little to get a little overdrive. The amp weighs 48.5 lbs on the bathroom scale, about 2 lbs lighter than the Bassman. I'm going to haul the amp over to a different music store to have some unbiased ears give me some feedback.

I still don't know how to upload or make videos, so I can't let you hear it. Maybe some day.....

Diablo · 09-13-2009, 06:49 PM

Well I thought I was finished, but decided to do a little tweaking. I added a 150K resistor across the treble pot connected to the ground switch, so I can change the voicing of the amp - scooped midrange. Goes from Tweed Twin to a not quite blackface.

Duncan Tone Stack Calculator

tubeswell · 09-14-2009, 12:34 PM

... yes I too find that the tweaking usually goes on for some months after the build is 'finished'

...

Diablo · 12-14-2009, 09:35 PM

Another tweak. I changed the power scaling from only the power tubes to the whole amp. This reduces the overall gain available, but there's still plenty for me. And it just sounds better.

Diablo · 12-17-2009, 03:10 AM

And yet another tweak. Swapped in a pair of EL34s in place of the 7027A tubes. The amp now has less of a Fender flavor. According to the local music store owner, he thinks it sounds like a Hiwatt. The EL34s add some bass and midrange punch and change the tone of the overdrive.

Big Mike · 12-29-2009, 01:39 PM

Good looking build!

Diablo · 12-29-2009, 09:47 PM

Thanks all for the kind comments.

09-10-2009, 02:52 AM	#1
Diablo Senior Member Join Date: Dec 2007 Posts: 501	Tweed Twin 5E8-A Finished Build Here's a link to some photos of my finished build. It started as a Ted Weber kit and I added the following mods: Vari-watt from Skipz-circuits 1K - 3 Watt screen resistors 1.5K - 1/2 watt grid stoppers on V1 and V2 Safety diodes (1N5408) on the rectifier Single RCA 5U4GB rectifier EH 12AY7 tubes in V1, V2, and V3 Shugaung 12AX7 in V4 RCA 7027A for the PA (biased at 45mA and 434 volts) 22 mfd/ 500 volt cap for first filter Heyboer Multitap OT # 18343 Atlas Amps 5E8A Tweed Twin with Vari-watt - Album - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting

09-10-2009, 07:47 PM	#3
tubeswell Supporting Member Join Date: Feb 2007 Location: Wellington NZ Posts: 2,658	Very tidy - I'm keen to hear how the variwatt affects things (when you are ready) __________________ Building a better world (one tube amp at a time)

09-14-2009, 12:34 PM	#6
tubeswell Supporting Member Join Date: Feb 2007 Location: Wellington NZ Posts: 2,658	... yes I too find that the tweaking usually goes on for some months after the build is 'finished' ... __________________ Building a better world (one tube amp at a time)

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09-10-2009, 01:08 PM	#2
stingray_65 Senior Member Join Date: Sep 2008 Posts: 214	GR8 job! layout is nice and neat. how does is sound??

09-10-2009, 08:52 PM	#4
Diablo Senior Member Join Date: Dec 2007 Posts: 501	Thanks gentlemen. There were no problems with the build, and I didn't have to chase any strange hums or noises, so the ground scheme must be OK. I've never played or heard a 5E8A before this one, so it's kind of hard for me to give a critical comparison. I tried to find the 57 Tweed Twin RI at the local guitar center, but they don't have one in stock for me to play - but they'd be willing to order one for me..... It was funny, they'd never heard of a Tweed Twin before I mentioned it and told them it comes from the Fender Custom Shop. Anyway, if I compare it to my 5F6A, the amp is more midrangey and at the same time very sensitive on the treble control. It also breaks up earlier with a more singing distortion. The Variwatt does work as described. I can adjust the plate voltage down from 434 volts to 12 volts, and the bias tracks along by itself. I can crank in huge overdrive when the VW plate voltage is reduced and sound like Led Zep, but I find the most use in it just reducing the plate voltage a little to get a little overdrive. The amp weighs 48.5 lbs on the bathroom scale, about 2 lbs lighter than the Bassman. I'm going to haul the amp over to a different music store to have some unbiased ears give me some feedback. I still don't know how to upload or make videos, so I can't let you hear it. Maybe some day.....

09-13-2009, 06:49 PM	#5
Diablo Senior Member Join Date: Dec 2007 Posts: 501	Well I thought I was finished, but decided to do a little tweaking. I added a 150K resistor across the treble pot connected to the ground switch, so I can change the voicing of the amp - scooped midrange. Goes from Tweed Twin to a not quite blackface. Duncan Tone Stack Calculator

12-14-2009, 09:35 PM	#7
Diablo Senior Member Join Date: Dec 2007 Posts: 501	Another tweak. I changed the power scaling from only the power tubes to the whole amp. This reduces the overall gain available, but there's still plenty for me. And it just sounds better.

12-17-2009, 03:10 AM	#8
Diablo Senior Member Join Date: Dec 2007 Posts: 501	And yet another tweak. Swapped in a pair of EL34s in place of the 7027A tubes. The amp now has less of a Fender flavor. According to the local music store owner, he thinks it sounds like a Hiwatt. The EL34s add some bass and midrange punch and change the tone of the overdrive.

12-29-2009, 01:39 PM	#9
Big Mike Junior Member Join Date: Dec 2009 Posts: 1	Good looking build!

12-29-2009, 09:47 PM	#10
Diablo Senior Member Join Date: Dec 2007 Posts: 501	Thanks all for the kind comments.

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