First express build first try finished

Express, Liverpool, Rocket, Dirty Little Monster, etc.

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boops
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First express build first try finished

Post by boops »

Hi and thanks all for all the great infos ,I ve founded here;)
I'm planning to build my first TW express
Don't find in any schematic about ,how to connect the 3 poles/3 positions impedance pot,help with a schema, please .
Last edited by boops on Sat Feb 11, 2017 9:59 pm, edited 1 time in total.
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M Fowler
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Re: First express build first try finished

Post by M Fowler »

The Express build guide has some information: Trainwreck files section

I don't use that type of switch in mine.
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boops
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Re: First express build first try finished

Post by boops »

:wink:
Last edited by boops on Tue Jan 10, 2017 8:47 pm, edited 1 time in total.
boops
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Re: First express build first try finished

Post by boops »

M Fowler wrote:The Express build guide has some information: Trainwreck files section

I don't use that type of switch in mine.
Many thanks,I ve already read this excellent build doc ,what do you used ,a cheap LORLIN?
Is a classic solution without pot possible with a 5/10r 10w ,or a shorting jumper on the jacks ?
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M Fowler
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Re: First express build first try finished

Post by M Fowler »

There not cheap switches I use these.
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boops
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Re: First express build first try finished

Post by boops »

Great...thanks
;( I ve done my order from mojotone ,yesterday ,(the OT TW 35)
They ask me the same 35 usd shipping for this switch ;(
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dorrisant
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Re: First express build first try finished

Post by dorrisant »

$10.00 here... or a few bucks cheaper if you know somebody. :wink:

https://www.tubesandmore.com/products/s ... 3-position
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M Fowler
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Re: First express build first try finished

Post by M Fowler »

http://hoffmanamps.com/MyStore/perlshop ... D=!ORDERID!

$8.18 from Doug Hoffman a member here.

Also regarding shipping on order sites if you look around the shipping page you can select cheaper methods I found that out the costly way. Some sites are nice enough to note the cheapest shipping others think you want the part tomorrow so they put the higher shipping on the order. Can always call too.

Mark
boops
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Re: First express build first try finished

Post by boops »

Thanks so much.
boops
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Re: First express build first try finished

Post by boops »

I live in France,there isn't even ,one ;( ,but I have an old ampli tube stock little shop With nice parts for amp build,pics soon.
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Ron Worley
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Re: First express build first try finished

Post by Ron Worley »

The switch I showed in the build guide is the original Stackpole (now Electroswitch) that Ken Fischer used in earlier wrecks.

Ken wired 2 gangs together per impedance position in order to get enough wattage margin to handle the OT.

Later, I believe Ken used the Lorlin style switch shown above by Mark Fowler. It's a hell of a lot easier to use- I just used the old Stackpole because I happened to score a bunch of them surplus, and they were what the originals used.
Ron
boops
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Re: First express build first try finished

Post by boops »

Thanks you,for all the great infos shared here,chapeau bas messieurs ;)

I ve finished this express,this morning,this is my first tube amp built
And I've decided to use parts ,I wanted to make a try in this world ,awaiting the parts for the final one with 6v6,I think.
I ve bought the OT TW35 from mojo and a Hammond PT 372 jx from mouser
An impedance pot.
I use :
12ax7 NOS Philipps,GE,SYLVANIA 1962/63 ,El34 EI ,6v6 Mazda 1952
Allen Bradley 2w pots,1% carbon comp resistors NOS some nos Mullard mustard caps
I play guitar since 38 years now ,mesaboogie mark 2A 1979
Princeton blackface fender strat,and fender esprit with hambucker,for reference.
I will make a sound demo asap
The sound and feeling is different for me ,it's really amazing: clear,bright,loud , and great with an old fuzz pedal with a lot of sensitivity sure and ,no hum
BUT BUT BUT i had to backward the Ot primary,a big squeal at the first ON /OFF
And there is a lot of hiss white noise,even with the volume at 0 ,I can hear my guitar a little ,it get louder as I turn up the volume, and my presence pot make a bad noise when I turn it , the function seems to works fine ,thought it is new .



I ve added a grid stopper resistor of 33k on pin 7/V1 ,a ferrite bead too
Tomorrow I will try to put a 12au 7 (17 gain) at v2 ,and an orange drop 2,2nf
Is a lot of hiss is normal,even if it's a high gain design ?there a lot of microphonie at v1,no hiss without it.
Ideas welcome
Pics of amp not finished but working ...

[img:1024:768]http://i1235.photobucket.com/albums/ff4 ... l4kq7e.jpg[/img]
[img:1024:575]http://i1235.photobucket.com/albums/ff4 ... gkcf5i.jpg[/img]
Last edited by boops on Sun Feb 12, 2017 10:00 pm, edited 1 time in total.
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M Fowler
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Re: First express build first try finished

Post by M Fowler »

Congrats on your build.

All the things you noted are common with this amp.

For that presence circuit you may need to move the wire from pot to impedance selector around and see if that helps.
boops
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Re: First express build first try finished

Post by boops »

M Fowler wrote:Congrats on your build.

All the things you noted are common with this amp.

For that presence circuit you may need to move the wire from pot to impedance selector around and see if that helps.
Thanks ,the last night ,I ve found a lot of advices about hiss,here again :)
I will try to make a separate ground for the presence pot.
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