100w 2nd Gen. ODS build

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martin manning
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Location: 39°06' N 84°30' W

Re: 100w 2nd Gen. ODS build

Post by martin manning »

You are referring to this layout?
https://ampgarage.com/forum/viewtopic.p ... 80#p462380
If you bolt the reg to the chassis and solder the legs to a terminal strip (as in the later ODS layouts) you already have two grounds: the tab, and the center pin (via the terminal strip). In the linked diagram "RPS ground" is just a ground lug (if the reg is board-mounted), or it can be the grounded center lug of the terminal strip. The reg is grounded (twice!), so you just need to connect the lower capacitor negative and diode anode to the grounded lug. It's ok to have more than one ground if they are in that corner of the chassis and close together.
DSull89
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Joined: Mon Nov 19, 2018 3:05 pm

Re: 100w 2nd Gen. ODS build

Post by DSull89 »

Thanks again, Martin! You’ve been a big help! When my parts show up I’ll post some progress pics. :)
Thanks,
Dan
DSull89
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Joined: Mon Nov 19, 2018 3:05 pm

Re: 100w 2nd Gen. ODS build

Post by DSull89 »

A little more progress, but wanted to ask a couple questions before I went any further. On the 1Ω cathodes is it best to ground them in pairs, individually or am I over thinking and it doesn’t matter? Also, as far as the 100 Ω filament grounds, does it matter which sockets I run them off of? I was thinking of going off pin 2 of V5 and pin 7 of V6 to be neat unless there would be an issue I’m unaware of. Let me know and thanks again to all that have been taking the time to help. Much appreciated. :)
-Dan
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martin manning
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Re: 100w 2nd Gen. ODS build

Post by martin manning »

DSull89 wrote: Wed Oct 08, 2025 12:09 am A little more progress, but wanted to ask a couple questions before I went any further. On the 1Ω cathodes is it best to ground them in pairs, individually or am I over thinking and it doesn’t matter? Also, as far as the 100 Ω filament grounds, does it matter which sockets I run them off of? I was thinking of going off pin 2 of V5 and pin 7 of V6 to be neat unless there would be an issue I’m unaware of. Let me know and thanks again to all that have been taking the time to help. Much appreciated. :)
-Dan
If you look at the #124 layout you can see that the heater and cathode grounds are grouped 3 and 1. Grounding in pairs or individually will be fine. Similarly you can do the 2x 100R off the same socket or from two adjacent ones. Here is how I did my ODS.
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DSull89
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Re: 100w 2nd Gen. ODS build

Post by DSull89 »

Thank you, Martin! Just the clarification I needed. Very nice work, too! Which ODS variation did you build and how do you like it, if you don’t mind my asking? :)
Thanks,
Dan
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martin manning
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Re: 100w 2nd Gen. ODS build

Post by martin manning »

DSull89 wrote: Thu Oct 09, 2025 12:44 am Which ODS variation did you build and how do you like it,…
That is a #124 with a few tweaks. It’s a great sounding amp IMO, and capable of producing a wide range of tones.
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