Ceriatone Overtone Special gut pics

[dogears]

Owners nixed the pix.... So, not for public display. Sorry!! You can post the front and backs I guess, just not guts.

Hey Rob,

Is that a 158K Slope resistor? I'd pop 150K in there and see if you like.

Also, did you ever get my PM regarding the pics I gave you?

Hi Scott,

I'll check that out tomorrow, it's late here. yes I got your PM and I got the pics, it seemed so "hush hush" that kept quiet about the whole thing and I guess I didn't even reply to you. Personally I think the pics should go up, unless there's an owner who explicitly says no.

Rob.

[Pete]

The brown resistors are Vishay/Dale and are MF
CF in 124 pics are kind of tan/light brown in color. (these are the majority of the resistors used in that amp, IIRC)

I see what you're talking about. I'm not really up to speed in identifying a metal film based on the pics. I can tell a carbon film normally by looking at it, but this one just looks "brown".

[Structo]

Gil not to doubt you because you were there, but from the picture it looks like a carbon film slope resistor?

And of course #124 was a 100 watt amp so some of these values may or may not translate well to a 50 watt clone, yes?

Let's see: Scott suggested to Rob that he change the (apparently) 158K slope to 150K. I see the Ceriatone (Rob's amp) pictures and I see what looks to me like a metal film 1% in the slope position. So I add to Scott's recommendation and mention to Rob he may want to consider using a carbon film instead of the incumbent (which is another value and another type) when he puts a resisotr with the correct value there.

I am not sure what the mixup is, Structo.
Gil

Sorry Gil, For some reason my eyes read carbon film but my brain read carbon comp.........

[ayan]

[Sorry Gil, For some reason my eyes read carbon film but my brain read carbon comp.........

No problema, baby.

Gil

[Rob Livesey]

Hi chaps,

Just been tweaking the Ceriatone Overtone Special based on information shared here:

- Changed slope resister from 158k to 150k (Carbon Film).

- Changed resister before the OD trimmer from 150k to 220k (Carbon Film).

- Changed Level pot from 250k linear to 100k linear (Alpha).

The results are good. The amp is not quite as bright on the clean and the OD is sweeter and more open. The level pot is way more usable now and I can get that almost seamless transition from clean to OD. I'm a happy chappy.

Thanks guys!

I think I'll gig the amp some more and see how pre tube changes affect the amp for a while.

BTW: spent about five minutes scratching my head wondering why the amp sounded so different (not great at all) after I made the changes, until I realised I was plugged into the FET input - Duh!
I once watched Robben Ford all night plugged into the FET input by mistake and his tone really stank!

Cheers,
Rob.

[wbfree]

Hi, all you experts, I have been following this thread because I am a complete noob at this. I have the #124 schematic, but I don't know what it references, sorry for my ignorance. Is it the design Nik now uses or something else, so is there another schematic?

The reason I ask is I would like to do some of this stuff myself, I enjoy it but don't know much and it is very expensive to have a tech do everything for you.

Funk, thanks for the plan on the dumbleator.
Sorry for my noob questions........how else will I learn how to be dangerous with a solder iron.

[Pete]

I have the #124 schematic, but I don't know what it references, sorry for my ignorance. Is it the design Nik now uses

#124 is a Dumble ODS amp, I'm not expert on the Ceriatone Overtone Special but I think that is the schem used (with some minor changes)

so is there another schematic?

others are here: https://tubeamparchive.com/viewtopic.php?t=1902

[wbfree]

I have the #124 schematic, but I don't know what it references, sorry for my ignorance. Is it the design Nik now uses

#124 is a Dumble ODS amp, I'm not expert on the Ceriatone Overtone Special but I think that is the schem used (with some minor changes)

so is there another schematic?

others are here: https://tubeamparchive.com/viewtopic.php?t=1902

Thanks, now I have a question, How do you view these, when I save them and bring them up they are unreadable..? I must be doing something wrong but don't know what.

[dimitris]

wbfree wrote

Thanks, now I have a question, How do you view these, when I save them and bring them up they are unreadable..? I must be doing something wrong but don't know what.

First click on each picture with your mouse,a new window will open and then right click on the picture in the new window and save picture.
Hope that makes sense

[erwin_ve]

Hi Rob,

Is the tone you get with the overdrive mode less harsh in the low area after the mods you did? When I play the amp, particulary with strats, i had to reduce the bass to make the harsh less prominent.

edit: Removed the cap thing, that was really noob

[Rob Livesey]

Here's the resistor I'm talking about. Nik said they did use 158k for a while, but that they are all 150k now.

[img:600:450]http://personalpages.manchester.ac.uk/s ... ad/c8B.jpg[/img]

I don't find the Overdrive harsh, it's aggressive yes, but in a very good way. At first, before the mods, it was all a bit too much, the amp is much more controllable now. Regarding harshness, you really need to go through different speakers and cabinets to get the right combination.

Like I said in the Technical Forum, I just picked up a Boogie cab with an EVM12L (one of my favourite speakers) and it really does sound harsh with the amp. The Fuchs cab I have with the same speaker sounds really sweet.

Rob.

[erwin_ve]

Yeah, harsh isnt exactly the right word, i'm not a native english speaker.
Maybe a bit fuzzy, without the mods, in the lower region?

[Rob Livesey]

Yeah, harsh isnt exactly the right word, i'm not a native english speaker.
Maybe a bit fuzzy, without the mods, in the lower region?

Fuzzy would be a better description of how it was before. No, it's not fuzzy any more, I would say it's tight, thick, fat and articulate, I like it.

Rob.

[wbfree]

Thank you Dimitri, Appreciate that.

What speakers sound good? I have a Altec 417 8c, Celestion heritage series g12 65 and a scumback M75 with a large dustcap.

The mods you guys are doing I will have to take one step at a time, starting with the resistor on the 100k trimmer. I am not a tech, but I understand that might take some of that harshness out?

Thanks guys for all the info
Burnie

[jakeddy]

Hello, I am new here. I just got an Overtone and I am very interested in a few tweeks. I hope you'll be patient with me if I ask some dumb questions as I am not amp tech, just a guy looking for tone.

I'm looking at the resistor change before the od trimmer to start. Is there something/anything anyone would care to share?