EMI RS124

[thomasdf]

Here is what I have, I am not 100% sure it is an original one, despite what claims the seller. Solen caps and all ... ?
From the looks of it , only the 5th one from the back is a real unit... So no 100% reliable gut shot, I am sorry

 

[rock soderstrom]

Here is what I have, I am not 100% sure it is an original one, despite what claims the seller. Solen caps and all ... ?
From the looks of it , only the 5th one from the back is a real unit... So no 100% reliable gut shot, I am sorry

Thanks anyway! I think you're right, this is a replica or a total rebuild of an old device (Altec 436?). The components are definitely too new for the actual age.

 

[thomasdf]

There are some info and pictures in this thread, mostly of the same build ... a replica made by someone in the US, with some values hidden on some components : https://groupdiy.com/threads/feeler-altec-abbey-road-rs-124-build.41663/page-2

 

[rock soderstrom]

There are some info and pictures in this thread, mostly of the same build ... a replica made by someone in the US, with some values hidden on some components : https://groupdiy.com/threads/feeler-altec-abbey-road-rs-124-build.41663/page-2

It's crazy when you read it from today's perspective.

 

[heatwalk]

Were the originals just a new front panel but kept the existing altec chassis? The altec layout PTP is pretty simple since so few parts to follow if you take a minute to follow the components inside.

 

[rock soderstrom]

Here a gut shot from another John Hinson replica from a Reverb ad.


from

https://reverb.com/es/item/65411415-altec-emi-rs124-rare-abbey-road-tube-compressor

 

[rock soderstrom]

Were the originals just a new front panel but kept the existing altec chassis?

Allegedly the interior was completely rebuilt, but I have only read that on the WWW. I expect the RS124 to have more European components, perhaps Mullard Mustard caps?? Photos could show that...

 

[heatwalk]

Ah. Curious what would have demanded a complete rebuild vs adding to existing. Additions like the feedback 100ks wouldn't require additional lugs to solder in. Maybe the techs wanted to beef up their billable hours…

A period build would be pretty rad but all the .02/400 mustard caps in the world are sitting in Marshalls / marshall clones these days

 

[rock soderstrom]

A period build would be pretty rad but all the .02/400 mustard caps in the world are sitting in Marshalls / marshall clones these days

I've found some for a good price!

https://reverb.com/de/item/46117715...-mullard-mustard-capacitors-marshall-lead-set

Joking aside, I actually still have very few

 

[thomasdf]

I decided to go with the usual suspects in my builds : Nichiden, JJ as well as some TAD and some vintage Cornell Dubilier from my stash. Even a 1:1 period correct clone would not make me write / sound like Paperback Writer so ...

 

[rock soderstrom]

I decided to go with the usual suspects in my builds : Nichiden, JJ as well as some TAD and some vintage Cornell Dubilier from my stash. Even a 1:1 period correct clone would not make me write / sound like Paperback Writer so ...

I will use Mallory M150 for my first build for the 0.022uf positions. "They" use it in their 4k replica as well:

 

[rock soderstrom]

I have a question regarding the size of the required resistors in the main part of the circuit (i.e. not in the PSU).

From my point of view, I should be able to get by with 0.6 watt resistors everywhere.

But I see on photos of the official RS124 replica also 2 Watt types, for example in position R7 at the common cathode of the 6CG7.

Why?

If I use the values given in the schematic I get 46mW thermal load.

The 100k feedback resistors are also 2 Watt types. Do you really need that?

What is your experience on this topic? I'm almost done with my PCB design (I'm really slow) and just checking all footprints to see if they are big enough.