New Ceriatone OTS 50 Build

[eazilyled]

Here's my completed build.

It's a 50w OTS I built from a kit.
For transformers, I used Hammond bassman type replacements (PT 291DEX, OT 1760L, Choke 194B).

My voltages were a touch high initially (477V at power tube plates, ~200V at V1 plates), so I increased the 3K3 dropper resistor to 4k7.
This got the preamp plate voltages down a touch, so I ended up with ~190V at V1 plates.
I also adjusted the PI trimmer for a 6V difference at the V3 plates.

For tubes, I used some old Mullard ECC83s in V1 / V2, a new Tungsol in V3 and TAD 6L6s in V4 / V5.

Other than an intermittent standby switch which I suspect I caused through overheating, the build was pretty straight forward and luckily it fired up first time.

I didn't build the head cab, I got that from Tube Town.

I'll probably invest in a G1265 loaded cab and some sort of Dumbleator eventually.

I'm quite pleased with the sound of the amp. I have to say it's a bit of a strange novelty to be able to use the master volume to keep the sound levels down - I've been used to having to use an attenuator with my Express build

[hywelg]

Nice..

Is that all stock Ceriatone parts except for the trannies?

[eazilyled]

Thanks. Yes all stock parts apart from the trannies which required new mounting holes, and the intermittent standby switch (used same Carling type). Come to think of it, I also swapped out the voltage regulator because I goosed it up when soldering.

I think I recognise your user ID from the Ceriatone forum?

[M Fowler]

The build looks good, now to get some play time on that amp, right

Mark

[eazilyled]

The build looks good, now to get some play time on that amp, right

Mark

Thanks Mark! Yes, playing is going to be a priority for me now, both for the purposes of break-in and pleasure

These D style amps are kind of epic in terms of build effort, so it's a nice reward to be finally able to play it.

[hywelg]

Thanks Mark! Yes, playing is going to be a priority for me now, both for the purposes of break-in and pleasure

Yes, I did spend quite a lot of time over at the Ceriatone forum, gone dead there now, hang out here a lot more, much more knowledgeable folks

My OTS did take quite a while to break in properly. I still found the OD a bit harsh when I have the clean EQ'd as I like it and that prompted me to fit a cut control to the OD. Works a treat.

[eazilyled]

Sounds good hywelg. I keep reading about doing the 'bright switch on clean only' mod which I believe achieves a similar effect as your mod.

[Structo]

No I believe he is talking about a simple tone control on the OD channel.
Some call it a treble bleed circuit.

It is a cap and trimmer to dial down the treble response of the OD.

The "Bright on Clean" switch mod adds another relay that turns on a bright cap when in clean mode.
I really like this mod.

Shown below.

[eazilyled]

Thanks Tom I may do one of those eventually. I'll see how it goes in a band situation first

[hywelg]

It is a cap and trimmer to dial down the treble response of the OD.
.

No its this one, caps only to bleed treble off

http://ampgarage.com/forum/viewtopic.ph ... 236#233236