Express into 60w

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

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idnotbe
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Express into 60w

Post by idnotbe »

first of all, sorry for dumb questions...

recently i got a Ceriatone Express with Pacific OT.
and i'd like to change the output into 60w -> full output of 2 * EL34 for the big transformer sound.


1. do i need to change only the power transformer?
or both PT and OT?

2. i will order the tranny from Heyboer and will have a local tech do the mod.
what does the local tech need to change, except connecting / re-wiring the new transformer?
for ex, does he need to change the power-section components with new values?

3. are there some reference schematics for 60w Express?

4. to reduce the risk of this 60w experiment, can i use Concorde tranny?
i found Concorde's voltage (~500v) is very different to Express (~400v).

5. why does Concorde use ~500v ?
i feel Express (~400v) is already stiffer side in tone. (than marshall)
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xtian
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Re: Express into 60w

Post by xtian »

Why go to the effort of changing the OT? Just remove two power tubes, and halve the speaker load.

EDIT: Duh. I was sleepy. Don't sleep and post. Sry. *mumble mumble*
Last edited by xtian on Sun Aug 06, 2017 5:51 pm, edited 1 time in total.
I build and repair tube amps. http://amps.monkeymatic.com
RockinRocket
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Re: Express into 60w

Post by RockinRocket »

Don't let the 35 watt Express fool you. The amp still sounds huge at 35w and is part of how the amp works/ responds.
The amount of money to buy bigger transformers and have a tech install it would not be worth it for a experiment.
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romberg
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Re: Express into 60w

Post by romberg »

idnotbe wrote: Sun Aug 06, 2017 3:03 am i'd like to change the output into 60w -> full output of 2 * EL34
I'm not sure you can even get 50w out of two el34s. The el34 has a maximum plate dissipation of 25w. To get 60 you may have to switch to something like 6L6GCs.
1. do i need to change only the power transformer?
or both PT and OT?
To get a full 60watts out of two 6L6s you may need to raise the plate voltage higher than the standard express value of 400. So, new PT. If your output transformer is say rated for 40w, then you will need to replace that too.
2. i will order the tranny from Heyboer and will have a local tech do the mod.
what does the local tech need to change, except connecting / re-wiring the new transformer?
for ex, does he need to change the power-section components with new values?
With higher voltages, the main power supply caps and bias circuit may need to be changed/upgraded. It depends on what is in there.
i feel Express (~400v) is already stiffer side in tone. (than marshall)
Since you could potentially be into most of the cost of a whole new amp with the above "mod" why not just build a whole new marshall style amp and leave the express alone?

Mike
Bob S
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Re: Express into 60w

Post by Bob S »

I know a couple of the guys (Allyn & M Fowler) built 80w versions of the Express :shock:
Not something you hear everyday "my Express isn't loud enough"
Unless you're playing Che Stadium without a P.A. I'd be more concerned with an airbrake.
A buddy set up for ban practice & unfortunately pointed 2 4x12 cabs at the drummer - Express with all controls at 5.
I got a funny phone call - "his eyes are open but he's not making much sense yet"
Why Aye Man
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M Fowler
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Re: Express into 60w

Post by M Fowler »

I would build a Komet 60 rather then the Express much smoother sounding.

Either way, your going to need the appropriate PT and OT.

Mark
idnotbe
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Re: Express into 60w

Post by idnotbe »

M Fowler wrote: Mon Aug 07, 2017 1:53 pm I would build a Komet 60 rather then the Express much smoother sounding.
Either way, your going to need the appropriate PT and OT.
thanks for the input, guys~!!
as you advised, it seems better to build another DIY amp.

i searched forums but i couldn't find Concorde schematics and layout. (maybe it is commercial?? )
i will be very very glad if you share Concorde build info such as schematics, layout, part list and so on.
Last edited by idnotbe on Tue Aug 08, 2017 6:59 pm, edited 1 time in total.
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M Fowler
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Re: Express into 60w

Post by M Fowler »

http://el34world.com/Forum/index.php?topic=22182.0

Way down towards the bottom of the post Barry shows his layout for the Asteroid same amp.

Mark
idnotbe
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Re: Express into 60w

Post by idnotbe »

M Fowler wrote: Mon Aug 07, 2017 7:59 pm http://el34world.com/Forum/index.php?topic=22182.0

Way down towards the bottom of the post Barry shows his layout for the Asteroid same amp.

Mark
Mark, always thanks for the kind answers.

and if somebody have Concorde (not K60) schematic / layout / part list, plz pm or e-mail me.
Mark
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Re: Express into 60w

Post by Mark »

I seem to remember the Concorde had a cathode follower stage after the third stage. I thought there was a circuit of it floating around. As far as I can remember it was similar to the K60, I recall builders thought it was a very rocky sounding amp.
Yours Sincerely

Mark Abbott
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