Ceriatone Overtone Special gut pics

[Rob Livesey]

You should really have 220K in front of that 100K trimmer, not 120 K.

Fixed

I'm going to try the 220k+100K trimmer setup that most of you are recommending, plus I'm going to go 100k linear on the OD Level. But, on some of those pencil sketch layout drawings, that resistor feeding the trimmer is clearly shown as 120k.

[img1944]http://personalpages.manchester.ac.uk/s ... 24036b.jpg[/img]

Rob.

[jelle]

But, on some of those pencil sketch layout drawings, that resistor feeding the trimmer is clearly shown as 120k.

Please keep in mind that these values are chosen to get a proper output imp for V1b. The 124 amp had 120K and a 350k pot equals 470K.

Most non HRM schems here have 220K with a 100K trimmer, equals 320K. These amps have the higher plates..220K, 150K etc

The higher imp (470K) helps to smoothen out the signal a little bit in the 124 amp that has 100k plates and can sound a bit agressive.

I hope this helps,

Jelle

[ic-racer]

But, on some of those pencil sketch layout drawings, that resistor feeding the trimmer is clearly shown as 120k.

Rob.

**EDITED** Ayan was present at the interrogation of #124 and is sure it is 220k, here are some more posts on the topic: **EDITED**

https://tubeamparchive.com/viewtopic.php?t=4362

Also, check out this picture ( https://tubeamparchive.com/download/file.php?id=2753 ) and there is discussion about it near the bottom of page 2. https://tubeamparchive.com/viewtopic.ph ... c&start=15

Personally, I am collecting some parts (thanks to Funk...) with the intent that I am just going to have to try a few things and see how they sound. Keep us informed as you tweak.

[Funkalicousgroove]

120K/350K= sounds good

220K/100K= sounds good

220k/350k= dark and muddy

120k/100k= bright and rhaspy

[ayan]

But, on some of those pencil sketch layout drawings, that resistor feeding the trimmer is clearly shown as 120k.

Rob.

I think it comes down to the resistor wasn't measured and its banding is difficult to interpret.

That is how urban legends are started. I was there, I heard the amp, I saw the resistor, I took a picture of it... and it is a 220K. And here is a blowup of it, just in case.

Regardles of what I or Brandon say, this is something very easy for you guys to try: 220K, 120K, 350K trimmer, 100K trimmer, etc. The amp in question was not muddy, but it was brown sounding.... both in clean and OD channel. In one of my own amps, with 220K + 100K trimmer, I tried a 250K Level pot (instead of the more common 100K) the sound was not brown: it was downright shitty.

Gil

[dogears]

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?

[ayan]

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?

And if you will be replacing that, Rob, you might as well consider using a carbon film resistor there. Dumble favored them for the slope position in all I have ever seen with Dales on the plates.

Gil

[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?

[ic-racer]

That is how urban legends are started. I was there, I heard the amp, I saw the resistor, I took a picture of it... and it is a 220K. And here is a blowup of it, just in case.

I was actually serious when I posted this poll: https://tubeamparchive.com/viewtopic.php?t=4362

Without that good closeup, 120K won. Thank you for posting this last picture. I will change my schematics accordingly.

[ic-racer]

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?

Thanks for pointing this out. The Overtone layout that Niki has on his website shows a 150K.

[Funkalicousgroove]

Well, that CERTAINLY is a 220K!! I tried this and didn't care for it much, I like 120K MUCH better with the 350K trimmer, just my $.02

[ayan]

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

[ayan]

That is how urban legends are started. I was there, I heard the amp, I saw the resistor, I took a picture of it... and it is a 220K. And here is a blowup of it, just in case.

I was actually serious when I posted this poll: https://tubeamparchive.com/viewtopic.php?t=4362

Without that good closeup, 120K won. Thank you for posting this last picture. I will change my schematics accordingly.

That is actually too funny! As Scott mentioned in the other thread, I had told him it was a 220K a couple of years ago - has it been that long?

Gil

[Rob Livesey]

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.

[Rob Livesey]

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

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".

The Ceriatone layout diagram has this specified as a 150K, so I can only asume that the 158K value is either a mistake or a substitution. How much difference does 8K make, it would be good to know?

I will change this, just becasue I'm that kind of guy.

BTW, I love this thread, I'm learning so much !

Cheers,
Rob.