Please help me identify this amp

[IneedHelp]

I inherited what looks like a 1970's kit-amp and I really need help finding out what it is. There is no writing on it of any kind except for "Radio Filter" imprinted on a small box connected to the power cord. It was my father's (who was an electrical engineer), and it was "bundled up" with a Southwest Technical Products Corporation (SWTPC) "198/A Preamp" (found here: http://www.swtpc.com/mholley/Catalog6/Page01.jpg). I searched the internet for pictures of SWTPC kit-amps of that era, but had no luck. I know my dad built both of them, so I would love to put them to good use, but I don't want to hook them up without knowing more (especially about the power amp).
Thanks in advance!

The following pictures are:
(1) Amp front-exterior (2) interior (3) Filter? connected to cord (4) rear-exterior
   

[tonyharker]

Difficult to tell from the small pictures, but from the appearance of those transistors with square heatsinks, it looks to be a variation of a Tiger amplifier from Popular Electronics magazine. Are these transistors RCA types with the numbers 40409 & 40410?
If the outputs are TO3 types 2N4909, & 2N4915 then the amp is likely 100w/channel.

[IneedHelp]

Yes, the transistors are 40409 and 40410. The outputs are RCA 40411 (TO3 NTE181) which I guess means it's 70 watts per channel?

[tonyharker]

Not a Tiger then as I think all they were all Fully Complementary.  Probably a generic RCA design, 70 watts for sure.

[IneedHelp]

Not too bad - thanks for the help  :tu:

Here's the top-view for anyone who is interested:

[J M Fahey]

It sure brings fond memories !!
I built most of them, way back then, and never stopped (built over 10000 amplifiers by now).
It's a stereo  "Brute 70".
Your Father built it almost by the book, with the only small difference in mounting the PCB very close and parallel to the heatsinks, instead of inside the chassis ; which would have required a very-difficult-for-the-amateur rectangular cut in the chassis.
An excellent amp and, yes, as Tony Harker correctly remembered, based on one of the groundbreaking RCA 70W versions.
Here you have it in all its glory:


For the full articles:
http://www.swtpc.com/mholley/PopularElectronics/Feb1967/PE_Feb1967.htm
Congratulations.

[IneedHelp]

I can't believe you found that - thank you! 

[J M Fahey]

I didn't find it ... it found *me* , about 42 years ago .... and never let me go, he he.

[IneedHelp]

 

[Jack1962]

YEah JM , I still have 1 of those myself  :lmao:

[IneedHelp]

I play in a band and we play small to medium gigs and occasionally a party or wedding - the only thing is, we don't have a PA, so I was thinking of somehow turning this amp (and preamp) into a PA. Maybe I would encase the amp into a "head" and then make a cab like this one (http://www.instructables.com/id/Building-a-Solid-pine-wood-finger-jointed-guitar-/) or this one (http://www.miyakodesigns.com/sidestripe.html). I have done a lot of woodworking in the past, but think it would work? It might not be loud enough though - any suggestions? Thanks

I also have a Behringer GMX212 (120 watts) that the first one (the black one) would match nicely with. I play a LP through it and it sounds pretty good about half way up - but it's not clean enough when we play a show because I have to crank it almost all the way.  

[J M Fahey]

For PA use you may use the Brute70 as a 70+70W power amp, driving 2 boxes, each with a good, efficient guitar type speaker (Jensen MOD1270 or C12N/K, Eminence Legend, Celestion from 65 to 80W, etc.) plus 3 or 4 piezo tweeters for highs.
Voice will come out loud and clear through them.
Use any cheap mic mixer you can get, or a simple box type PA head driving 2 cabinets and the Brute70 driving two others.
Don't worry about dovetails, "good" wood, fancy finish.
PA speakers are happy with simple Chipboard or Plywood construction , painted with latex black paint.
When you scratch them, you touch them up and they look as good as new.
Avoid MDF or buy an extra back.(for you, not for the speakers, he he).

[IneedHelp]

Thanks JM, I'm going to do that for sure. I just need to decide how I want it to look. Thanks again for your help.  
Oh, I almost forgot, I was thinking about 2 x 12's, , with the tweeters you were talking about, but then 4 x 10's seemed workable too - what do ya think?
Rich

[J M Fahey]

2x12 or 4x10 are fine, but remember you will need 8 ohms for each channel.