Bremia S30-A From Argentina

[custom_amp_30]

Here is the link to a Amp that I purchased. Its a Public announcement Tube amp from Argentina with an input voltage of 220 Volts 50/60 Hz Transformer. I was lucky that I also received the owners manual with diagrams so it shouldn't be to hard to put it back together.

6SJ7
6SN7
6C5GT
6L6
6L6
83

Think I'll make a Tag-board/turret board to better organize this mess. There are bad solder points from the last guys attempt and a few broken components like the 200 Ohm power resistor.

Bremia pictures by 73GTV - Photobucket

To bad that I don't read the language but I do understand the diagram which I will post at a later date. Thanks for looking.

[J M Fahey]

Post whatever you need translated.
I wonder how it got there, specially with manuals and all.
Scan and post whatever you can.
It should make a terrific Blues amp.
*All* electrolytics must be dead by now.

[Steve Conner]

That's a beautiful looking amp! You have to fix it up. If it were me, I'd gut it down to the transformers and tube sockets, and start again with fresh components. As JM said, those old electrolytic can caps are almost certainly dead, and I wouldn't trust any of the other caps or resistors much, either.

The vents in the transformer end bells remind me of the Italian Geloso amps.

Too bad that it ended up in a 120V country, though: there doesn't seem to be any way of converting it to 120V without using an external transformer.

The high secondary voltage means that it has a choke-input filter, so watch out there. If you convert it to a capacitor-input filter as used in 99% of guitar amps, you'll get a stupidly high B+ voltage, enough to fry and burn things.

[J M Fahey]

Good suggestions.
I'd say please respect the original power amp. Rebuild it with new components but the same schematic, including the power supply.
After all, it works!! and has done so for ages.
If anything, get creative with the preamp, although in due justice, I'm sure rebuilding it as-is (following the original schematic) will give a beautiful, raw, vintage sound.
It must clip real smooth and sweet.
It's very probably a Geloso knockoff, given that they were *very* popular in Argentina, doubly so by our heavy Italian immigration (Europeans were an incredible 60% of Buenos Aires population in 1915).
Edit: worst case, replace only the power transformer, with an equivalent one, or use a lower voltage one, to be able to build a modern PSU with the same +B voltage.

[custom_amp_30]

Nice, I was wondering if any information on the original company could be found in Argentina. The only thing that I found was a radio on a sales search.

This was a EBay purchase back in 2006 from a site in Atlanta, Georgia. I bid $12.00 I believe and drove down to the EBay site/store and paid cash since I happen to be in town visiting my sister within about an hour after arriving, drove to that part of North Atlanta and put in in the front seat of my truck. Its been in storage until I settled down.

I have the diagram and will follow it to the letter and keep the values the same. Actual have the spares laid out for this build. I can get a 120 - 220 Volt power transformer to power it. The original Power transformer is 550 - 0 - 550 at 166 mA.

[custom_amp_30]

First name of company:" Nuestros laberatorios al desarrollar este amplificador no han querido crear un producto 'unicamento comercial".


So I am guessing that "Nuestros Laberatorios" is the parent company? Can't scan it in due to the size of the diagram. Thats ok.

[J M Fahey]

"Nuestros Laboratorios"means "Our Labs", so it's just a generic description.
If you have a reasonably good digital camera, set it on 1600x1200 or similar resolution, not higher, what's important is to set "quality" to "superfine" or "best", set the manual or schematic outside with good light (so as to avoid flash) , and snap a couple pictures with a steady hand.
Set it to "no flash" and maybe a "macro" setting will help.
You may brace yourself or your forearms against a wall or some furniture.
Push the button smoothly, do not jerk the camera.
Before posting open them on your screen and check that even small text and component values are still readable.
You'll get best light close to a white wall that receives sunlight or in a bright yet overcast day or when a big cloud covers the Sun itself.
This is the best option for larger-than-scanner originals.
I found a little info on Bremia: they were PA and Radio makers (think 1946), then Radio/Grammophone console makers (1950's) , then Transformer suppliers (early 60's).
Obviously their iron is the best part of the amp.
Combinado Antiguo Bremia - $ 700.00 en MercadoLibre
DeRemate.com.ar: ANTIGUA RADIO CAPILLA ART DECO CON OJO MAGICO DE COLECCIÓN - $ desde 1.00

[custom_amp_30]

Thanks for the update. I decided to post the diagrams section that I did have scanned from the original document. 1946 Cool. Well at least we know it works...

[J M Fahey]

WOW!!
Now that I see the schematic, plus instructions, I have a better idea of what it is.
There was a strong industrialization in Argentina beginning in the late 40's (which died a bloody death *literally* in the late 70's), with lots of new companies offering amp and radio kits.
They had the winding machines and put them to good use, making transformers, chokes, and radio coils.
The kits were a way to sell those to the public.
Every little town had a respected "radio man" who churned out whatever was needed, on demand.
As you can see, here you have a lot of "wound iron": power transformer, input choke, screen choke, driver transformer and the output one.
¿Does yours have the speaker out (4/8/16 ohms) or the line out one? (500/200 ohms)
Check the code as indicated in the schematic.
I retract from one earlier suggestion: pull the power transformer, ditch the "83" and the input choke"React B 3706" (although you can leave them on for looks) and use a 300+300 to 320+320 VAC power transformer, and a substantial capacitor input power supply, as on any classic Fender 2x6L6 amp.
Also ditch the "R44 20K 25W" power resistor, which was used as a brute force voltage adjustment, and add a resistor in series with "React 2 B3701" to bring screen voltage down to specified 325V. Start with 1K 2W and go on from there. Also increase the value of filter electrolytic ¿C14? to 47uF (or the ancient wording of "mfd").
It will make an excellent harp or smoky blues guitar amp, also perfect for the 1947 class dance reenactment. Don't forget the announcer's crystal mike, crystal pickup turntable (78 rpm of course) and a couple 15" Jensen field coil speakers. If anything, you are allowed a couple of those newfangled Alnico permanent magnet ones.

[custom_amp_30]

0 - 165 - 250 - 500 Ohm.





Thanks Your advice will be followed. Plus I have other uses for that 83. I like the stand alone Amp for the Living room next to the small flat screen...LOL Thanks for your help.

[custom_amp_30]

Well I decided that I would remove and set aside the original transformers and chokes.

I have a few ideas a new use of said chassis and will post the results.

You can see that I have a choice of Power supplies for this build. Lets see where this goes.

[custom_amp_30]

The power transformer is a 120 Volt / 400 - 0 - 400 at 300 mA.( Red red and red and yellow) with a 5 volt 3 Amp secondary.(Yellow) The green according to specs is (2.5 V/2 amps), and brown (2.5 Volts/ 2.5 Amps).

Need to test this since it was a recent purchase sometime last week. ($10.00)

Ok Now that the picture stuff is done for now. I'm thinking of using the Mercury Magnetics OT for this project. I have to recheck the application for this OT. I think it may be for two 6V6's. Not sure about use with the 6L6GC have to return to that site and see.

I already have the boards assembled just have to check a few measurements.

[J M Fahey]

Good decision, but I think your Mercury 400+400 is way too high!! It will give you around 560V +B , unless you go for a choke input PSU. Is that so?

[custom_amp_30]

That may be the way to go, This is all test fit to see what I can actually complete with parts on hand. I could either make a circuit with two 6L6's or Four.

The Power Transformer is the 400 - 0 - 400. The Mercury was an upgrade for another amp.

[custom_amp_30]

Hummm! I was looking at a Fender Twin Amp Model 5C8 which uses 3 each 6SC7, 1 each 6J5, 2 each 5881 and 1 5U4G. it has the same amount of controls. Now I wish that I hadn't mounted the three spare nine pin sockets to the chassis in the open holes seen above; in case I was to use 12AX7 for a pre-amp circuit. Still Before I commit to the final design for this, I'm packing to relocate to larger quarters so this may take a few more days before I can get back to this build. (End of Lease, Only five days to move and cleanup)

Any positive of negative thoughts about the sound of this particular amplifier would be helpful. I will keep looking but any other suggestions would be considered.

6SC7 verses 6CN7?