Re: EMI RS124
« Reply #340 on: December 26, 2013, 01:48:29 PM »
Hi all-

So I am approaching "close to done" with my pair of RS 124's that I am building, based off the Altec 436 Drip PCB and the DIY.RACKED faceplate/enclosure. I have a few questions:


1- the "clean/dirty character" switch; it should add/remove R26 and R27 from the circuit via DPDT switch, correct?

2-would the hairball 600ohm T pad attenuator work in place as an output attenuator?

3-how is the stereo link switch, and the anode balance pot, wired?

Thanks so much for the help! (Edited, as i found some of the info i was looking for)
« Last Edit: December 29, 2013, 12:13:15 PM by rjd2rjd2 »


letterbeacon

Re: EMI RS124
« Reply #341 on: June 10, 2018, 04:42:44 PM »
I'm slowly gathering all the bits I need to attempt this one. I have a couple of questions though...


How can I work our the current draw for this compressor and is there a Hammond PT that's suitable? I was thinking that the 369AX might be ok, its specs are 250V C.T. @ 115ma, but it's tricky to know without knowing how much current I need.

I've never built a neon circuit before - what sort of neon bulb shall I look for? One that can take 110V, or are there other specs I need to look for.

Thanks for your help in advance.

Rob Flinn

Re: EMI RS124
« Reply #342 on: June 10, 2018, 06:07:36 PM »
You can normally work out the current flow through each valve using ohms law on a resistor where you have a voltage reading on the circuit.  say for example you had 1v across a 1K cathode resistor put the figures into ohms law V=IR so I = V/R .  SO you would have 1mA through that valve.  DO this for each half of each valve & add them all together.   You might be able to do this on an anode resistor if the diagram gives you the h.t voltage & you have the anode voltage.   Subtract the anode voltage from the h.t voltage then you know the volt drop across the anode resistor, do the same maths.   When you spec the transformer you probably want maybe 1.5x the current draw you calculate.
regards Rob

letterbeacon

Re: EMI RS124
« Reply #343 on: September 09, 2018, 05:42:31 PM »
I managed to get started on my RS124, and finished all the drilling this weekend.

I know it's the most exciting project, but I thought I'd post some pics because everyone likes a bit of DIY porn!

I'm using a Hammond PT, a Sowter OP TX and the original Peerless on the input.




djn111

Re: EMI RS124
« Reply #344 on: September 11, 2018, 05:18:33 AM »
Hi,

Looks good, can you be more specific on what you used ?

JJ capacitors by the looks of it ? and what chassis did you use ?

DJN

letterbeacon

Re: EMI RS124
« Reply #345 on: September 11, 2018, 09:53:01 AM »
Yes they're JJ caps on the back for the power supply filtering. The big one is 2x 50uf and the smaller one is either a 50uf or a 80uf (I can't check at the moment.

For the OP I'm using the Sowter they make for the Altec 436.

The case is from Holt Broadcast - it's their 150mm deep 2U one.

I'm moving house over the next week or so, but I hope to have a bit of a progress update soon.

r2d2

Re: EMI RS124
« Reply #346 on: October 03, 2018, 05:31:11 PM »
A very interesting project  :o

please there is  a bom list and a doc with some building info , advice , helps  , as well ?
(…Before Behringer "Strike" again…  :'( )
many thanks in advance.
cheers
« Last Edit: October 06, 2018, 06:31:43 AM by r2d2 »
..... Cracking D.Vader Firewall ...  II-)

djn111

Re: EMI RS124
« Reply #347 on: October 09, 2018, 05:10:25 AM »
Hi,

In you respond on help etc. This is just a building report, and if you need all that info, are sure you want to build a tube project, point to point with 300V DC in it ?

All the info is in a few RS124 threads, start reading those the parts list is not very big, so easy made from the schematic.

Kind regards

r2d2

Re: EMI RS124
« Reply #348 on: October 10, 2018, 06:10:13 AM »
Hi,
In you respond on help etc. This is just a building report, and if you need all that info, are sure you want to build a tube project, point to point with 300V DC in it ?
All the info is in a few RS124 threads, start reading those the parts list is not very big, so easy made from the schematic.
Kind regards
Thanks for post !

i checked fully this 18 pages thread , … many variations (Altec , Emi , VarMu …) and different cool buildings   ::)
(but no part list or scheme about)
also different schematics scattered here and there on the pages ,

but what schematic is much similar to the actual commercial (authorized) reissue version ?  ::)

also checked some other thread here as well  ,
i agree about  not much parts are required ,
but not found any info about parts sources ,

anyway i only asked
if a scheme and a parts list also as pencil written draft were  available for share , also by "request" ,
 ( as for the big part of projects available here )

cheers

ps :
Before China Behringer "strike" again…   :(
(after "76" ,  "A2A" , EQP1 , who's the "next" ? )
« Last Edit: October 10, 2018, 05:42:07 PM by r2d2 »
..... Cracking D.Vader Firewall ...  II-)

djn111

Re: EMI RS124
« Reply #349 on: October 11, 2018, 11:55:00 AM »
Hi,

Copy of a comercial unit is not done, to much trouble in the past about that kind of thing including lawsuits etc.

But recreation of a old unit, why not.

So let's see what you need schematic ? do you have that ?

Also there is more info on this site about the RS124, also on the Drip site is/was helpfull info on the forum pages.

Check the origanl compressor, wich is adapted to te RS124.

And from the build post, you can derive, power transformer, input and output, tube sockets etc.

Kind regards

Kind regards Dirk Jan


 

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