Ceriatone Forum

I'm kind of in the same boat as all of you waiting for my overtone parts. I have ordered the boards and hardware and cabinet to use for my project.

Here is the chassis that I already have, getting some original Switchcraft components (redily available in USA).
http://img.photobucket.com/albums/v670/ic-racer/Chassis2.jpg

As you may know, Nik's version of the overtone is 50w. I am re-creating an amp with 100w output. This requires a custom powersupply (to match the original D amp). The original had 300uf capacitors, which are difficult to locate.
http://img.photobucket.com/albums/v670/ic-racer/BigCaps.jpg

Since the original used Fender transformers, these are easily available in the USA, so I have these already installed on   the chassis. http://img.photobucket.com/albums/v670/ic-racer/Transformersinplace.jpg

Unfortunatly, I must wait for my parts from Niki to do any more with the project.

Here is another picture of the underside. Unlike Niki's power transformer, the original Fender transformer does not have a 6v tap for the relays and Leds. So, like the original D amp, I have added a small 6v transformer.
http://img.photobucket.com/albums/v670/ic-racer/t_6v_pt_846.jpg

If anyone is interested in specific part numbers on the transformers let me know, am glad to share the info with anyone else building an overtone.

Uhhh this is going to be cool.
I want to watch this ... subscribed

 ;)

IC-Racer,

Is that one of songwut's chassis'?

I got the chassis at a swap meet here in the states. I don't know where it originally came from, do you have a link to songwut's chassis? Maybe it matches.

Check it out here.
http://vasinguitaramp.tripod.com/id4.html (http://vasinguitaramp.tripod.com/id4.html)

He also has some interesting Fender clone chassis kits on ebay.  I might have to pic one of those up to try out with a rehouse of my severely beat up Super Reverb chassis.  Item number is 320207423520

If that D clone chassis is the same as yours be aware that you may have grounding issues as I think he annodizes the chassis.  Depending on the type and degree of annodizing you might be ok with scaping and sanding a clear spot but most likely (to be certain) you should think about drilling and tapping and installing ground lugs.

I think the originals were anodized also. Here are some pictures of where I believe Mr D used these star washers to ensure adequate ground on the components that need to be grounded to the chassis.

Likewise, on my chassis I used the washers over areas that I scrapped with a Dremel. Turns out, on the original, these speaker output jacks get the ground through the chassis, where as many of the other components have a separate ground wire.

Updated shot of the chassis.

50/100 switch and LED.

where did you get the control panels?
which fender trannies did you use?  Twin style?
How do they differ from what Nik uses (other than the output wattage?)

thanks for sharing with us!

Hi,

I got the chassis locally, but from the looks of it, it is available on the internet. The chassis came screen printed with all the lables.

Since I used Hammond replacement/reproduction Fender Twin transformers. They are made in USA and Canada and are reasonably priced. I got in on a "Holiday Special" and got free shipping (25LBs!) when I ordered the transformers. I chose Fender Twin transformers because thats what Mr D used in the 80s. Niki's amp is a clone of an 80s style amp.

The original output transformer only has a 4 ohm tap (just like an 80s style original amp). The chassis I have only has the single 4 ohm speaker output also, so everything fits together like the original. This output transformer is also for four 6L6 tubes.

The power transformer only has input taps for 120v and has no 6v output. This is different than Niki's transformer, but it is exactly like the original 80s amp.

Keep posting on your build progress...good fun.

Just heard my parts will be shipping Monday!!

Any day...impatiently waiting...

Very nice, I can't wait for it to be finished..... so I can play it.
B 8)

the original used musicman transformers

Fender OT, not MusicMan.
(http://img.photobucket.com/albums/v670/ic-racer/ODS_124027.jpg)

ic-racer....  I sent you a pm about your build and your transformer selections
Thanks,
Scott

Just got my extra parts from Niki, and things are moving along. Here are some recent pictures:


(http://img.photobucket.com/albums/v670/ic-racer/testfittingcomponents.jpg)
(http://img.photobucket.com/albums/v670/ic-racer/pilotlight.jpg)
(http://img.photobucket.com/albums/v670/ic-racer/busbar2.jpg)

Pictures of the amp just after I finished it!

(http://img.photobucket.com/albums/v670/ic-racer/undersidefinished.jpg)
(http://img.photobucket.com/albums/v670/ic-racer/Finished2.jpg)
(http://img.photobucket.com/albums/v670/ic-racer/finished1.jpg)

Man I was following this build on the TAG forum and man this is impressive.
You have some great skills.


Let us know of any mods you might do.

 ;)

Nik told me he has 100 watt version of Overtone special available now... Has anyone built one?

Nope... 50 watts is more than enough for me. But I hope someday he builds an HRM version (50 watt or 100 watt). :)

Only reason I would want 100 watt is for the clean headroom... My plexi 50 is loud on clean but I don't know if its enough for gigs.

Here are the final pictures.

(http://img.photobucket.com/albums/v670/ic-racer/DSCF3829m.jpg)
(http://img.photobucket.com/albums/v670/ic-racer/DSCF3860m.jpg)
(http://img.photobucket.com/albums/v670/ic-racer/DSCF3855m.jpg)

Sound clips:

http://soundclick.com/share?songid=6435261
http://soundclick.com/share?songid=6430994

Her is the info for the 6v transformer:

41FD010                       1        6.810            6.81
         Xicon Heavy Duty Pow
         TRANS FIL 6.3V 1A

From Mouser.com

Awesome sound ic-racer! I really like it.

Sounds great and nice playing !!!

I tried out some different 12AX7s and found a phase inverter tube that could be perfectly DC balanced with the trimmer.

Here is the latest sound clip:

http://soundclick.com/share?songid=6455534

Very sweet ic-racer.  8)

Just to summarize how different or similar my amp wound up being compared to the Overtone:

Different chassis (black adonized aluminum)
PT and OT are Hammond Fender Twin style
Four 6l6 tubes
50/100 switch and LED to indicate 50w mode.
Standby switch wired like a Dumble
Strict adherence to Dumble grounding scheme and lead dress
2 resistors to 'lift' the heater voltage from ground, like Dumble
Separate relay transformer
290uf caps (Dumble had 300uf)
350k OD input trimmer
4.7uf on V2 in place of 1.0 uf
Switchcraft jacks throughout, except FET jack, which is Kobicon.
Ground switch wired with a center off switch.
Main power LED powered with external diode and resistor
4 Bolt carrying handle put on the cabinet
Fender chrome corner protectors put on the cabinet.
Aluminum pieces on front of cabinet replaced to look like original
Once I get my hands on some black Fender grillcloth, this will go on the front plate.

With the exception of a few component changes listed above, and changing the color of some of the wires on the boards, the Ceriatone boards were pretty stock. (The Ceriatone Power Capacitor board was not used)

Thanks for your input that was a great build.
 ;)

How important is it to balance the PI? i its something i dont know how to do, nor do i have the eqiupment. I assume you would have to bring up both +and- signals on a oce and match the signals osciloscope.

I cannot really say. The tube I chose that allowed me to get a perfect DC balance may have just been a better sounding tube (irrespective of its 'balance'). There is not enough range of the balance trimmer to really get my tube 'out of balance' enough to hear any difference to easily compare.

I have not started dinking round with the tubes in my OTS yet. But I have a lot of experience with the tubes in my super reverb. The biggest variable* factors affecting its tone, and point of break up are the pre-amp tubes (mainly V2 since that is the channel most used) and the PI tube. A balanced 12AX7 in the PI is mandatory. I use JJ ECC83S from Eurotubes. He sells exactly what  he advertises. He tests and categorizes all his 12AX7s. You buy the tube "balanced", the balancing is a virtue of the manufacturing process. Not something that you do to the tube. The 12AX** tube has two halves. On the PI tube each side feeds the output tubes 180 degrees out of phase. It is not important to know what that means, but in knowing that much you can see why you would want the 2 outputs of the tube to be matched or "balanced". I have found this to be very important, especially at higher volumes.

* I am assuming that you will not be changing speakers or other soldered components on a frequent basis. The pre-amp and PI tubes seem to have much more affect on tone than the Output Tubes.

One thing I forgot to mention.  I am using an output transformer with a single 4-ohm tap and I am running this into an 8-ohm speaker or cabinet. From what I can tell,  lot of 100w Dumbles were used this way.

Nice build...sweet sounding amp you got there ;D

Another sound clip with a locking tremolo guitar.

http://soundclick.com/share?songid=6505247

Beautiful ic-racer - what a great sound! :D

what kind of speakers do you use?

I don't have a dedicated speaker for the Dumble yet. I have been using the speakers in the various combos I have. Currently my favorite is a Celestion Modern Lead 70 that happens to be in a Sundown 50w Combo. My second choice (of the speakers available to me) is a 4x10 Alnico set that resides in a Mesa Blue Angel combo. I have Celestion vintage 30s in a 2x12 combo and in a 2x12 closed back Mesa cabinet. Neither sounds real good with the Dumble. So, I'm still looking for the best speaker...

What an incredible sounding build!  You do amazing work!

Do you have a layout or something that shows what you did to make the 100 watt version?

How did you wired up the 50/100 switch, the standby switch and, the 2 resistors to 'lift' the heater voltage from ground?

When you write that you strictly adhered to Dumble's grounding scheme and lead dress. What exactly does a builder do to emulate his technique?

Are the transformers you used the Hammond 100 watt 125A29A & 022889?

Those sounds are so sweet!

I have a schematic that shows everything! It shows how the 50/100 switch is wired and exactly where it is grounded. The schematic shows all the grounding points. Lead dress was copied exactly from the #124 pictures on the internet. To make it easier I tried to copy the wire colors also (but did not have enough of some of the colors, though)

Lets see if the schematic will post...

Well, time for some major tweaking. I totally redid all the cathode, plate and grid values to match the Dumble values. Here is the latest schematic. Soundclips to follow.

and... ???
do you like it better than before


 ???

Just finished it last night, so it may take a few days to get a good impression. Here is a sound clip:
http://soundclick.com/share?songid=6562082

I can't seem to upload the PDF schematic, the upload screen just freezes. I'll try later.

Well, it sounds a little brighter but if thats your game why not.
To me it's important how the amps sounds with the band. I guess with a tone like that you should have no problems... but on the other hand you lose a little of that D smoothness IMHO.

 ::)


BTW awesome playin'

I like that very much. Really old school rock!


Very, very good. :)


Marin

It does seem to "rock" more with this 'older' circuit. I can't help but thinking old Jackson Brown etc and those silver face ODS amps. From what I gather #124 was near the point where HAD moved away from the 100k amps. I heard #123 had 220k and 150k on the plates. So, he intentionally made #124 more like those older amps (which had 100k on the plates).

Another 80s amp I was thinking about when I did the parts swap was this amp, owned and played by Gregor Hilden. I suspect it also has 100k plates: http://www.youtube.com/watch?v=h0NAofXeieM

Still deciding if I like it or not.

http://soundclick.com/share?songid=6564934
http://soundclick.com/share?songid=6564969

Ok, wrong guitar on those last clips.

Same amp settings and same amp layout (verbatim #124 values). Now it rips. This is with a Telecaster. I'm happy!

http://soundclick.com/share?songid=6573514
http://soundclick.com/share?songid=6573528

My impression is that #124 was created for single-coil guitars, but it's just a guess.

If you ask me, there was nothing wrong with those first clips.  ???
I can only hear, that this amp can do both guitars quite well... just the matter of taste what you prefer.

 ;)

Exceptional good tone with your tele!  Your 124 build really rocks.

So, my thoughts from reading this board and the AMP GARAGE board, and after my experimentation with #124 circuit that someone with an Overtone that plays primarily SINGLE-COIL guitars, might want to try going to 100k/1.5k/10uf on V1 and 100k/1.5k/4.7uf on V2 and compare it with the 220k/150k mod. on the "Modded Overtone" layout.

Or even a combination of resistor values can sound good. I just saw this today.
A Zion (Single-coil Strat style guitar), plus a Red Plate Dumble style mod with 100k on V1 and 220k/150k on V2 amp. In a live setting this can yield great tone.

This is Tim Betts playing and originally posted by www.RedPlateAmps.com

http://vids.myspace.com/index.cfm?fuseaction=vids.individual&videoid=34850007

Ok, now I have it figured out.

 #124 may have been built for a single-coil guitar!

My #124 really sounds killer. But with a double coil guitar it is too harsh. If you put a patch cord in the effects send/return, it activates the 220k/270pf network (if you wire it like #124) and this turns the double coil guitar sound into butter smooth tone!

http://soundclick.com/share?songid=6575515

Compare this to the same double coil guitar/pickup and and same amp settings wthout the 220k/270pf network (ie no patch cord jumper between i/o jacks)

http://soundclick.com/share?songid=6564969

I need to get my notes in order but where this is heading is a second overtone mod for folks to try. This one will be for single-coil players, and basically it will involve changing the Overtone components to #124 Dumble values.

To make a useful post on the mod, I need to go through all the changes and pick out the 'main ones' because there are about 50 differences and only a few would be needed.


Stay tuned....

Wow!  This sounds really interesting.  Your amp sounds great!!

In case anyone wants to experiment here is the basic mod:

V1A 33k grid, 100k plate, 1.5k cathode, 10uf cathode
V1B 220k grid bridged with 500pf, 100k plate, 1.5k cathode, 10uf cathode

OD input 220k into 350k trimmer (available from Antique Radio Supply)

V2A 68k grid, 100k plate, 1.5k cathode, 4.7uf cathode
V2B 180k grid, 100k plate,1.5k cathode, 4.7uf cathode

keep the 270pf/220k network on the i/o jacks, have it wired so it is only in place when you put a patch cord between In and Out. It makes a cool addition to the BRIGHT, MID BOOST and JAZZ/ROCK switches. (I guess if you still wanted to use the effects loop, and liked the 270pf/220k effect, you could use an extra hole on the back of the Overtone for a little DPDT switch)


Those are the main changes. It really moves the amp away from the "Modded Overtone"' schematic, but my amp sounds great with a Strat and Telecaster like this.
BTW: I did not come up with any of this, all these changes are exact values chosen by  Mr. Dumble.

Here is a final picture of my chassis. It is now just a 'distant cousin' of the Overtone, but it did start as an Overtone Kit.

Here is my finished cabinet. Again, this started life as an Overtone cabinet from Nik.

Some recent sound clips:

Clean with an Gibson ES135: http://soundclick.com/share?songid=6684380

Here is an interesting sound clip I made. It compares three amps. The first is my ODS. Next is a stock Mesa Trem-o-Verb orange channel. Third is a Fender Super Twin Reverb with a Dumble mod. All three amps were recorded and miced through the same Celestion 12" speaker. Fender Telecaster Guitar.

http://soundclick.com/share?songid=6584689

Here is another interesting composite recording comparing two amps. The first is the ODS and the second is a Sundown A-36. Again, both were recorded through the same speaker with the same guitar. In this case the guitar was a Gibson ES135.

The Sundown amp has a Marshall style tone stack after the overdrive (like an HRM).

http://soundclick.com/share?songid=6687158

nice tones and playing bro