3rd Generation Period Correct ODS 50W

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talbany
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3rd Generation Period Correct ODS 50W

Post by talbany »

Here is a 3rd generation ODS 50W..

3rd generation made around the 1978-1979 Ser# around 60-75..
Since these alterations occurred around a 2 year time frame and more than 1 or 2 amps and for the sake of accuracy should be referenced as 3rd generation ODS and shouldn't be looked upon as tweaks or custom voicing s for a certain customer..
Changes are listed on the top right of the layout are


1 Treble: 250KA treble pot

2..005 soldered between the wiper and top of the Bass pot

3.Black RG59/U 75 ohm foam - similar looking as the Tandy Wire RG59/U 75 ohm foam in ODS #094,(see below picture) but without the "Tandy Wire" label

Although this layout wasn't taken from an actual 3rd generation specimen perhaps I'll run across one here in the future..If so I'll make another separate layout better reflect the accuracy's of that amp (3rd Generation)



3rd generation "pre-classic" clips: (Posted By Max)

http://ampgarage.com/forum/viewtopic.ph ... 117#135117
http://ampgarage.com/forum/viewtopic.ph ... 120#135120
http://ampgarage.com/forum/viewtopic.ph ... 121#135121

Clean sound of a 3rd generation "pre-classic" Overdrive Special 50W combo with 12" Altec 417-8H Series II with a paper dust cap mod

Karl Ratzer "I Fall In Love Too Easily"

Karl Ratzer – guitar
Karl Hodina - accordion

Don't miss Karl Hodina playing his accordion!
More discussion

http://ampgarage.com/forum/viewtopic.ph ... 428#138428

Here you find clips of all the ODS generations from David Lindley's 1st generation ODS up to the skyline-HRM amps in the #200+ range: http://ampgarage.com/forum/viewtopic.ph ... 06&start=0


Enjoy Tony
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" The psychics on my bench is the same as Dumble'"
talbany
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Re: 3rd Generation Period Correct ODS 50W

Post by talbany »

#70
Export

This amp appears to have a buffered send added to the loop..Not standard on all 3rd generation amps..

Tony
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Last edited by talbany on Mon Apr 25, 2011 6:34 pm, edited 2 times in total.
" The psychics on my bench is the same as Dumble'"
talbany
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Re: 3rd Generation Period Correct ODS 50W

Post by talbany »

Ser #70
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Drumslinger
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Re: 3rd Generation Period Correct ODS 50W

Post by Drumslinger »

Many thanks Tony.
marcos
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Re: 3rd Generation Period Correct ODS 50W

Post by marcos »

Tony,
thanks for posting this. You know I love this stuff.
I wonder if this is the amp I have seen in 1994.
If so, it did not have the loop at the time.
Funny, nobody was talking serial numbers at the time, it was
just a Dumble amp then
Marcos
pazzo63
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Re: 3rd Generation Period Correct ODS 50W

Post by pazzo63 »

EXCELLENT WORK TONY!!!SICILY ROCKS!! DD
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mdroberts1243
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Schematic for #70

Post by mdroberts1243 »

UPDATED: Thanks to Stevlech for catching a couple of errors in the schematic... I should've used a larger printout of Tony's layout!

I've tried to create a schematic that checks out against Tony's layout.

There was some confusion in the FET circuit as a ground connection seems to be missing between some components and ground connection to the board isn't indicated in the layout. Also, I don't have a pinout for the relay so the schematic is a best-guess.

The photos posted seem to show some Send/Return jacks with a resistor network on them and an extra preamp tube, but the layout (& schematic) currently only have a preamp out jack. There seem to be some differences in resistor values from #70 too... so I've renamed the schematic to be a 'generic' 3rd-gen low-plate instead of relating to #70 specifically.
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Last edited by mdroberts1243 on Sat Apr 23, 2011 1:49 pm, edited 1 time in total.
-mark.
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Cause & Effect Pedals FET Dream and Dumble Style Chassis
andyhardy
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Re: 3rd Generation Period Correct ODS 50W

Post by andyhardy »

Awesome work!

Thanks
stevlech
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Re: 3rd Generation Period Correct ODS 50W

Post by stevlech »

Not to be a nitpicker, but has anyone else noticed #70 has 47k grid stoppers on stages 2,3, and 4?
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mdroberts1243
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Re: 3rd Generation Period Correct ODS 50W

Post by mdroberts1243 »

stevlech wrote:Not to be a nitpicker, but has anyone else noticed #70 has 47k grid stoppers on stages 2,3, and 4?
What about the fourth preamp tube? :)

Definitely not the same amp as layout.
-mark.
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Cause & Effect Pedals FET Dream and Dumble Style Chassis
stevlech
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Re: 3rd Generation Period Correct ODS 50W

Post by stevlech »

What about the fourth preamp tube?
Fx loop added after the fact, right? Tony mentioned it in the post.

Sorry if I seemed like I was calling you out- that wasn't my intent. I was just looking over the pics and caught the discrepancy.

Have a good day.

P.S.- thanks for the schematic. One more for the wall... :D
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mdroberts1243
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Re: 3rd Generation Period Correct ODS 50W

Post by mdroberts1243 »

stevlech wrote:
What about the fourth preamp tube?
Fx loop added after the fact, right? Tony mentioned it in the post.

Sorry if I seemed like I was calling you out- that wasn't my intent. I was just looking over the pics and caught the discrepancy.

Have a good day.

P.S.- thanks for the schematic. One more for the wall... :D
No offense taken... I agree there are some inconsistencies, but I don't know the back-story about why Tony decided the layout was representative of the 3rd gen low-plate.

I was mainly concerned with matching the layout in the schematic... I'm curious as well about the other details, but I'll let the changes be driven by the layout and try to keep a consistent set of documentation.
-mark.
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Cause & Effect Pedals FET Dream and Dumble Style Chassis
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mdroberts1243
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Re: 3rd Generation Period Correct ODS 50W

Post by mdroberts1243 »

Schematic slightly updated and reposted. Thanks Stevlech!
-mark.
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Cause & Effect Pedals FET Dream and Dumble Style Chassis
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sonicmojo
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Re: 3rd Generation Period Correct ODS 50W

Post by sonicmojo »

Awesome! Thanks for revising the old schematic. I am still researching and getting parts my 2nd/3rd gen build so this will help a great deal.
talbany
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Re: 3rd Generation Period Correct ODS 50W

Post by talbany »

No offense taken... I agree there are some inconsistencies, but I don't know the back-story about why Tony decided the layout was representative of the 3rd gen low-plate.

I was mainly concerned with matching the layout in the schematic... I'm curious as well about the other details, but I'll let the changes be driven by the layout and try to keep a consistent set of documentation.
Mark
Nice work on the schematic..Wonderful addition to the 3rd gen amp..

Here is the back story on the 3rd gen layout..

The 3rd gen layout was not taken from #70 or any one amp for that matter ..It merely reflects the generic changes or upgrades that were made over a series of amps to classify these as 3rd generation..I listed these changes in the opening post..I posted these pics to show lead dress and various component changes from 2nd gen to 3rd..Obviously I couldn't use # 70 as a 3rd gen layout, due mainly to the grid resistors & buffered send add on that was not standard circuit in all 3rd generation amps and IMO should be left off the schematic..Dumble obviously made certain tweaks here and there but the layout is the common thread that runs through all 3rd generation ODS's...If anyone has proof to the contrary let me know and I will be happy to revise the layout
BTW..I received my info from several sources that have been inside many ODS's

I hope this clears up any confusion

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