New Build: Ceriatone Replica OTS 50W

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norburybrook
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Re: New Build: Ceriatone Replica OTS 50W

Post by norburybrook »

drew wrote: Tue Jun 13, 2017 10:19 pm It looks like Ceriatone solders the resistors vertically to the sockets and connects the pairs with short lengths of wire.

https://www.flickr.com/photos/137947485 ... 765451275/
that's how I've always done it, however I've never thought of it as being particularly rugged from a mechanical point of view.


MC
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martin manning
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Re: New Build: Ceriatone Replica OTS 50W

Post by martin manning »

norburybrook wrote: Wed Jun 14, 2017 8:36 am...that's how I've always done it, however I've never thought of it as being particularly rugged from a mechanical point of view.
Thousands of Marshalls have been done that way, and it's not a common failure point AFAIK.
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ToneMerc
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Re: New Build: Ceriatone Replica OTS 50W

Post by ToneMerc »

norburybrook wrote: Wed Jun 14, 2017 8:36 am
drew wrote: Tue Jun 13, 2017 10:19 pm It looks like Ceriatone solders the resistors vertically to the sockets and connects the pairs with short lengths of wire.

https://www.flickr.com/photos/137947485 ... 765451275/
that's how I've always done it, however I've never thought of it as being particularly rugged from a mechanical point of view.


MC
Ceriatone copied the technique from Dumble and obviously HAD was ok with it.

TM
dwietzel
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Re: New Build: Ceriatone Replica OTS 50W

Post by dwietzel »

Thanks for the great information.
dwietzel
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Re: New Build: Ceriatone Replica OTS 50W

Post by dwietzel »

Going to add a half power switch.

Has anyone seen it wired like this (see attached PDF) ?

If so, it seems to me all it is doing is adding the 10K resistor to ground and I am just not sure how that get's me to half power.

Any information would be appreciated.

Thanks,
Half Power for 4 6L6 Tube Amps.pdf
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dwietzel
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Re: New Build: Ceriatone Replica OTS 50W

Post by dwietzel »

I believe I have completed Step 4

4. Install OT and Choke. Wire:
a) screen grid leads
b) plate leads
c) cathode resistors(or wire if you don't use 1ohm's to ground)
d) pilot lamp power assembly
e) screen resistors
f) grid stopper resistors & Bus
g) attach OT plate leads.

Plus added the half power switch. NOTE: Moved the 1 ohm resistor to the half power switch from Tube 1 and 4. :-)

On to Step 5!
PT Wiring 2.jpg
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dwietzel
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Re: New Build: Ceriatone Replica OTS 50W

Post by dwietzel »

After doing some research I am really wondering whether the FET input is really worth having at all.

Should I wire it up anyway? I am use to the 1M input going into the Preamp board (aka. 5E3, 5F6A).

Seems both NOR and FET go to the board and so I am not sure if it would take a redesign to make this happen.

Would appreciate any information.

Thanks!
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norburybrook
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Re: New Build: Ceriatone Replica OTS 50W

Post by norburybrook »

some like it , some like me don't :D It's up to you. If you have the parts you might as well use them.


If you don't then you need an extra 150k resistor to ground at the end of your dropping string to bring the last B+ down to correct voltage.


Marcus
dwietzel
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Re: New Build: Ceriatone Replica OTS 50W

Post by dwietzel »

dwietzel wrote: Thu Jun 15, 2017 11:43 pm Going to add a half power switch.

Has anyone seen it wired like this (see attached PDF) ?

If so, it seems to me all it is doing is adding the 10K resistor to ground and I am just not sure how that get's me to half power.

Any information would be appreciated.
Half Power for 4 6L6 Tube Amps.pdf
Doing a bump on this question. Would like to understand how this reduces power to half. Obviously it is doing something to PT 1 and 4 but would like to understand more especially if it could have a negative effect on tone or life of the PT tubes affected.

Thanks
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dwietzel
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Re: New Build: Ceriatone Replica OTS 50W

Post by dwietzel »

norburybrook wrote: Sat Jun 17, 2017 3:12 pm some like it , some like me don't :D It's up to you. If you have the parts you might as well use them.


If you don't then you need an extra 150k resistor to ground at the end of your dropping string to bring the last B+ down to correct voltage.


Marcus
Thanks Marcus...since I am still a newbie I will go with the "as is" design. Who knows when my brother may plug his piezo PU from his fiddle in and play along :-)
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martin manning
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Re: New Build: Ceriatone Replica OTS 50W

Post by martin manning »

You get half-power inserting 10k resistors between cathode and ground on two of the power tubes because those tubes will be biased into near cut-off, pretty much the same as if you removed them from their sockets. You should mis-match the speaker impedance selector down one click when you do that. The FET booster is not just a high impedance input, it also functions as a clean boost.
dwietzel
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Re: New Build: Ceriatone Replica OTS 50W

Post by dwietzel »

martin manning wrote: Sat Jun 17, 2017 4:47 pm You get half-power inserting 10k resistors between cathode and ground on two of the power tubes because those tubes will be biased into near cut-off, pretty much the same as if you removed them from their sockets. You should mis-match the speaker impedance selector down one click when you do that. The FET booster is not just a high impedance input, it also functions as a clean boost.
Thanks Martin!
dwietzel
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Re: New Build: Ceriatone Replica OTS 50W

Post by dwietzel »

I think I have this wired up correctly but the layout and my brain seem to conflict for some reason.

Is there anyway to test that the Switched FET Jack and NOR jack are acting properly before I go on?

I am also a bit confused on the layout (areas circled) especially the Green line and A reference on the NOR jack. Can someone clear that up for me?

Thanks
Input FET-NOR wiring.jpg
Input FET-NOR layout.jpg
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dwietzel
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Re: New Build: Ceriatone Replica OTS 50W

Post by dwietzel »

martin manning wrote: Sat Jun 17, 2017 4:47 pm You get half-power inserting 10k resistors between cathode and ground on two of the power tubes because those tubes will be biased into near cut-off, pretty much the same as if you removed them from their sockets. You should mis-match the speaker impedance selector down one click when you do that. The FET booster is not just a high impedance input, it also functions as a clean boost.
Martin - looking at the FET board if it is a clean boost I do not see any voltage coming into the board. Am I missing something? Every FET boost design I could find would have 9-12V coming into it.
davebolden44
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Re: New Build: Ceriatone Replica OTS 50W

Post by davebolden44 »

The red wire going into the 150k 2w resistor is its power source
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