A Collection of #124 Information (Schematics, Layout, etc.)

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Structo
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by Structo »

Hey, you are not the only one confused.

Different amps label those two controls differently. Drive, Ratio, Level, Volume, Overdrive, etc.

Just remember the pot next to the bass pot is the overdrive gain, and the next one is the volume for it.
Tom

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mad_dog
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by mad_dog »

Is there anyway that we can replace the layout on the front page with the one posted on the 20th of May.

The 20th May layout looks 110% to me but the one on the front pages has a few mistakes that have been doing my head in.
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Structo
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by Structo »

Wrong section
Last edited by Structo on Thu Jun 24, 2010 10:53 pm, edited 1 time in total.
Tom

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Structo
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by Structo »

Wrong section
Last edited by Structo on Thu Jun 24, 2010 10:54 pm, edited 1 time in total.
Tom

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martin manning
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by martin manning »

Not to be moderating or anything, but this ps board is hardly #124, is it?
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Structo
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by Structo »

No you are right, I'll move it.
Tom

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martin manning
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by martin manning »

Thanks... I'm kinda' envious of the organization on the TW side!
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Structo
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by Structo »

Yeah that is nice how they organized it.
Tom

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Max
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Re: A Collection of #124 Information (Schematics, Layout, et

Post by Max »

ic-racer wrote:I have collected a lot of stuff on #124 and have organized it so that I could understand the amp and build an exact replica.

All the info comes from the net, so this is nothing new. Mostly I have just organized and re-arranged information.

First I will post the Schematic of #124. This is really a 'community project' and basically it is traced back to pictures of #124, and a pencil scetch by 'Billy,' along with commentary by Gill. Then the first real schematic was produced by ampdoc1. I then added a few things to the schematic, and odourboy took over and did the first 'complete' schematic, showing the FET input and all.

Using odourboy's work as a foundation, I added in numerous fine details that were available from the pictures.

The second schematic is a guess at what #124 may have looked like prior to modification in 1988. The schematic can serve as a generic early 1980s amp.

This fantastic layout was the creation of talbany, martin manning and the Amp Garage community.
Some questions to all who contributed and all who know something about the circuit of #124:

1. Are the layout and two schematics in this first post of this thread the latest revisions of this layout and these schematics?

2. Why does the "skyline" schematic specify a metal film slope resistor and the layout a carbon film slope resistor?

3. Why is #124 called a "transition" amp in the layout? I ask, because it looks for me just as any other usual 4th generation ODS?

4. Why does the "classic" "1984 schematic" show a 100k slope? As far as I know, 100K/150K slope is not one of the differences between the "classic" and the "skyline" tone stack?

5. Are you sure, that the two .01uF capacitors between the rock/jazz switch and the bus bar (near the bass pot in the schem.) are a part of both, the "skyline" and the "classic" tone stack?

6. Why do you think, that a different "trigger" trim pot value is one of the differences between a "skyline" and a "classic" tone stack?

7. Why does the "classic" "1984 schematic" seem to be that unsure about a lot of the tonestack values "(xyz)"? Is it not known here at ampgarage, what precisely is the difference between a "classic" and a "skyline" tone stack?

8. Is there any other schematic of a transition or 4th generation "classic" ODS here at ampgarage or at some other place in the www, we could be sure about to be "correct" ("correct" in the sense of "existing at least in one specimen of an original ODS with a classic tonestack")?

Cheers,

Max
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Structo
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by Structo »

Max I think the biggest reason the layout and the schematic don't agree on everything is because two different groups of people worked on them.

I think the schematic labeled #124_ 182 is the most accurate I have.
Tom

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ic-racer
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by ic-racer »

I don't know if it answers your question but that 1984 schematic is supposed to be a step back in time before Mr D modified #124.

Here is the thread that lead to the schematic.
http://ampgarage.com/forum/viewtopic.ph ... light=1984
Steavis
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by Steavis »

does anyone know what type of orange drop capacitors are used in this amp? It's impossible to read what's printed on the orange drop capacitors in the pictures.
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by Steavis »

had a better look at the pics. They're 6PS series caps. ;-)
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hans-jörg
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by hans-jörg »

Hi,
its a pleasure for me to read all this wonderful stuff about Dumbles, because I intend to build one up (0124). So my first visible steps in this great forum willbe to show up a small mistake in the layout. There is written above the Volume Pot: V1-7. It should be: V1-2. As long as I can read it from the schematic.
Sorry for my terrible English

Hans-Jörg
talbany
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Re: A Collection of #124 Information (Schematics, Layout, etc.)

Post by talbany »

Hello All..

First the layout has been done quite a while ago several years before the correct termonology on the various generations was known here...The preamp boards were not done by me and in a program I do not have so I cannot edit them easily ie carbon film resistors etc.. AFAIK the power supply and relay boards in the layout are as per 124# pics and not taken from any schematic posted here.. It does not do anyone any good to state that there are a few mistakes without telling me which mistakes they are so we can correct them and move on for those who want to build a 124 inspired..So if someone knows something that is wrong or not period correct please shout it out and I will be more than happy to correct them!!!

Second this is not my post it's IC's so I have to correct these layouts then he has to post them.. I've done this several times in the past and some of those changes have sat in my outbox for weeks.. I should possibly move the layout to a seperate post so I can have acess to it and not rely on IC...
Also if you do see a discrepency on the layout double check it with the 124 pictures (Faceplate labeling etc) since this is what the layout was originally done with... Before posting any possible error and save me the time in doing so..
Thanks to All for the contribution..

Tony
" The psychics on my bench is the same as Dumble'"
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