New ODS 100W build with pictures...

[ic-racer]

Now for something completely different...I was getting tired of the amp (already???) and decided to go ahead and change ALL the values to #124 values, just to see what it would sound like.

First off I replaced the input jack again. I forgot to order enough Switchcraft jacks when I built the amp, so I had a Chinese one from Radio Shack in there. The plug doesn't wobble around as much with the Switchcraft jack

Next I re-wired the OD relay. The Overtone has it set up so the relay is OFF when OD is ON (and I'm using an Overtone relay board). From the pictures, #124 is wired the other way around. It doesn't make much difference, but my OD switch on the back of the amp worked in reverse, but now it works correctly.

Then I went through the preamp and replaced the plates, grids and cathodes with #124 values.

I also did a few 'Voodo' changes, like putting a blue MF resistor in the slope position and putting a tantalum 1.0uf cap on the presence circuit (replacing the electrolytic cap).

How does it sound??

Well, it certainly is a different amp. Much brighter. Now it does sound good through my Vintage 30 cabinets. Sound clips to follow.

Here is the latest schematic. Basically it is almost exactly like #124 at this point.

[ic-racer]

Sound clip as a full 100k amp.

http://soundclick.com/share?songid=6562082

[UltraHookedOnPhonix]

Hey ic-racer!

I noticed that the OD relay is funky on mine too.

I attached a drawing, is this how you did it?

[IMG:647:924]http://i205.photobucket.com/albums/bb17 ... layMod.jpg[/img]

[ic-racer]

Hey ic-racer!

I noticed that the OD relay is funky on mine too.

I attached a drawing, is this how you did it?

My relays are a little different. The two 'stationary' connections are at the end, rather than in the middle.

If you are showing the bottom relay in the OFF or non-energized position, then that is functionally how I have mine wired on my Clone and the Fender conversion. So LIGHT ON = FOOTSWITCH ON = RELAY ON = Overdrive ON.

[UltraHookedOnPhonix]

OK, cool!

[tubedogsmith]

Sound clip as a full 100k amp.

http://soundclick.com/share?songid=6562082

I thought that sounded great. The high strings have it going on and the low strings keep the clarity, don't get muffled. good job!!

[Luithien]

Sound clip as a full 100k amp.

http://soundclick.com/share?songid=6562082

Nice clip! Very Steely Dan to me...

JT

[makrisp]

Sound clip as a full 100k amp.

http://soundclick.com/share?songid=6562082

Nice Clip.

[ic-racer]

So, after living with the amp as 100k for a while I think I finally found the missing piece of the complete 'tone picture'

THE GUITAR!

From my humble observations it seems that the 124 SCHEMATIC (I didn't mention the #124 AMP, because I have never heard it) is best suited to a Stratocaster (or other single-coil guitar).

I tried a lot of things to get my amp to have a 'grail tone' with a Les Paul or other double-coil guitar. I swapped the resistor values back and forth from 100k to 200k, I swapped tubes, adjusted the OD trimmer back and forth, tried 4 sets of output tubes at various biases from 25 to 45 and I tried all the speaker combinations I own. And I tried almost every combination of USA and Chinese 12AX7 in the three preamp tube positions.I tried Les Pauls with high and low output. I got some usable sounds, but nothing really fantastic.

Then I plugged the Stratocaster in and immediatly I could tell this was a good match. All 5 pickup positions sound good in all 4 modes on the #124 style amp. And the mid boost is voiced just right to give a humbucker type sound the the strat's bridge pickup. The "Bright" is a little too bright, but I don't have the #124 value there. I have 270pf and I am going to change this to the correct #124 value of 300pf.

So, looking back at the #124 schematic, It is my opinion (suspect to change at any time ) that the values in that schematic were chosen by HAD for a customer who intended on using a Strat type guitar.

Specifically, the 10uf cathode bypass caps work well with the strat. The 350k OD trimmer allows more gain to pass through, offsetting the Strat's lower output pickups. The clarity of 100k architecture in the clean channel is a tried-and-true combo for the strat. The master volume capacitor seems fitting with a Strat. The 250k level control could, as suggested, be left-over from the Skyliner conversion, but in principle it also would shunt less gain to ground, and again, be consistent for use with low-output pickups. Having a 'brightness' network on the effects loop also seems consistent with Stratocaster tone.

To me, it all seems to make sense. What do you guys think?

Let's see how BobW's #124 amp sounds.

[dogears]

If you set it really high. However, at yoru settings, the voltage divider is not gainier than the standard 220K into 100K trimmer. Main difference is the lower knee due to RC, and the increased series resistance. IMHO.

The 350k OD trimmer allows more gain to pass through, offsetting the Strat's lower output pickups.

[ayan]

To me, it all seems to make sense. What do you guys think?

Let's see how BobW's #124 amp sounds.

The clip sounds good, with a little too much buzz in the bottom IMHO. I ditched the 250K drive pot in favor of a 100K... and the murkiness went away with the change. Never tried the 350K trimpot, I use a 100K one. My incarnation of the 100K amp sounds good with a Strat, although not as good as my amp with the Classis TS and the 220K/150K plate load resistors, and it absolutely rips with my 335. If would be easy to check the effect of the smaller resistors by paralleling something to what you already have.

Gil

[ic-racer]

So here are the 'single coil' clips with the verbatim 124 values.

I don't play the Telecaster much because I can never get it to sound good, but WOW, this thing rips with the #124 values. The definition in the bass notes of this Tele is fantastic. I've never played this guitar through an amp that has such good bass note definition.

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

What you can't see is the grin as I'm playing. I have never had such great sounds pop out of the Tele before

[ic-racer]

... too much buzz in the bottom ...

Yes, agree! The thing that gets me is that all that buzz is still in the amp but with the Tele, it does not come out or it adds to the instrument's tone. Check the most recent clips. Same amp values and settings as the buzzy clip but Telecaster instead of Howard Roberts Fusion III semi hollowbody.

[ic-racer]

I am waiting for perhaps my final Mouser order on this build. I have had good results with every change from ceriatone values to #124 values. This last round of changes will fix some values that are 'close but not exact.'

I'll be changing 270p caps for 300p caps.
470p changing to 500p.
Some components will change to the correct brand (just for the 'visual mojo')
Currently I have RadioShack 1.5k CF on the cathodes for testing and 1.5k RN-Dale's will be fitted.

A few more little changes and changes in resistor type to match #124.

When I'm done my schematic should be identical to to #124.

[bluesfendermanblues]

I don't quite see the point in changing component values as you have listed. It will not provide you with any different tone, going from 470p to 500p. Capacitor types can have an impact on sound, but off course not as much as component value itself.

What's the point in having an amp identical to #124, you never played the amp, heard a soundbite of it. It sounds to me like you should build yourself an additional amp.

I understand exchanging sound files and mod ideas, but not the strive to have an amp with visually identical interior. Just my tow (european) cents.