The AM Forum

I don't know how much interest there is here in old radio broadcast equipment, but I have been collecting it for the last couple of decades. Along the way, I have come across a lot of information (and a lot of myths) regarding studio broadcast boards. Since my interest is mainly--though not exclusively--RCA, that's what I have collected the most information on. If anyone is interested, I have posted a brief rundown of the RCA 76 series of consoles on my web page at http://www.kwd-radio.com (http://www.kwd-radio.com/). Just click on the "Consoles" link on the left. The information is pretty condensed, but it's the sort of stuff I wish I had been able to dig up way back when...

Maybe its just my P.C. but I cannot get the link to work.

73,
Joe

Two different people have told me the link doesn't work but I can't replicate the problem. Try copy/pasting the URL and see if that works.

As of 9:30 AM EST, the link fails.

http://www.kwd-radio.com/

Error 404 - Not Found

The document you are looking for may have been removed or re-named. Please contact the web site owner for further assistance.

Just tried it, and it works fine from here. Your ISP could be having some routing problems.
Doug

It is a Firefox specific problem.. Works fine on Chrome, IE 11, Opera..

Great site!

Odd. Very odd.

Hard to imagine why Firefox would give and error, and sure enough mine does!
Perhaps post a link that is deeper in the website??
Maybe that will work.

Strange.

                 _-_-

Worked fine first time.

Like the tellie fones.


klc

The link works OK on my Android phone.

Great site -- so much to read and see. Warms the heart of an ex-RCA (video) engineer of 31 years with the Corporation.

Bob - NE

Thanks for the compliments. I started the site years ago, partly as a way to gain a better understanding of html and website design. From what I've been able to find, some of the internal headers in my code just don't agree with some browsers (most notably Firefox, apparently). Much of it is still a work in progress. I think it might be time to start working on some code modernization.

Norton, in their "safe search" category, your site also comes up as untested. I use "safe search" with Firefox. If you Google kwd-radio with Firefox, you site comes up with KWD Radio and a [shaded box with a ?] If you as the site owner click on the shaded box you can have them "test" your site. Maybe there's a connection with Firefox.

Maybe not well known, but a number of web site hosting providers have tighten up their security protocols over the last several months. Many of the older versions (and some not so old) versions of various browsers are not longer (or soon will no longer) be supported. I go through this with customers at least once a day.

I just tried your site from the link Pete posted.  I am using Win 10 with Microsoft Edge browser and your site was a fast load.  I like that.

The link worked fine this morning as it does now. IE/Win7 pro.

Interesting site. Good job. One issue though: the 'General Radio modulation monitor' shown in Other Broadcast equipment looks more like the small RCA console...

Still doesn't work with Firefox V 41.0.1.  Always worked for my IE 11, Win 7 Pro.

 Nice site

Bill,

I am glad to see that the wonderful photo of WMRN's transmitter room my father worked at in 1941 is getting viewed by the world.

Working on chrome both using lte connection and wifi.

Tested on Chrome for Ubuntu on my server,  works.

Tested on Firefox,  did NOT work.   HOWEVER,  when I copy a link from chrome and paste into Firefox (ie,  copied the url for his ham link) and it works.

Points to a Firefox issue....   Probably with his home or index page naming convention.

The following link DOES work in firefox:

Http://kwd-radio/WEB_files/welcome.html

Sr.  Network Engineer in a previous life....

--Shane
KD6VXI

Quote: "the 'General Radio modulation monitor' shown in Other Broadcast equipment looks more like the small RCA console"

D'oh! You are correct. When I added that page, I used the RCA BN-2A console photo as a placeholder and forgot to change it. Thanks.

Hi Tom,

I'm curious - How do you suppose they controlled the transmitter blower noise from coming over the mic?  With no glass barrier, you would think it would be a problem ?? Then there's the problem of heat during  summer without air conditioning in the '40's...

T

Many stations used remote studios over landlines but still maintained a working, bare bones studio at the transmitter site in the event of problems. Wonder if that was the situation here?

Hi Tom,


The BTA-250L in the photo was convection cooled...no fans.

73DG

And the staff wore suit and ties at work during those days. No casual dress or shorts........a lot of smoking in the studios to clog the circuits up with the slime.........that's what is was 'back then'

There are some  :D that still do that in today's times. Here's Joe, N3IBX, with his BC-610:

(http://www.eht.com/oldradio/arrl/2004-04/Vortex-Joe-K3IBX-1.jpg)

Nice site. The link worked for me. Having started working in radio in the seventies spent lots of time removing and replacing vacuum tube consoles, monitoring and processing equipment and at that time no one had any love for that stuff.  Maybe in the forties and fifties when that stuff was new it was good but by the seventies it was all old, unreliable and preformed nowhere near as well as the cheapest solid state equipment. Like you I am amazed to see the price this stuff sells for today. Know of several RCA and Gates tube consoles that I gave away as late as the nineties and at that time very few wanted them and items like RCA program monitors, line amplifiers and the like often went straight to the trash. Back in the eighties I would always sell at the old Timonium Ham fest and drag a bunch of the RCA and Gates junk and never sold any of it. Things like patch fields, M-67 mixers and solid state Volumax and other solid state processing would sell at ham fest but not the old tube junk, maybe that’s why it’s worth so much today? 

Very cool picture of Joe (IBX).
Is it old before the equipment went into the basement/garage/remote shack or more recent and stuff is invading the kitchen?
Is there a T368 in the bathroom?

DOES NOT work in my  Mozilla FireFox

Fred

I cringe to think of all that stuff going to the landfill, but you're right. It's interesting how pieces did survive. I have a pair of RCA 70-C2 turntables from a tiny station in California that because a retired engineer heard the station was cleaning out the old stuff and it was going to the dump. He had no use for them but he saw them as pieces of history, so he put them in a shed for a few decades. Eventually, he sold them to the guy that sold them to me. My 76-C console survived because it spent most of its "active" life in a spare studio in a TV station as a backup. It saw little active service and is still in "very gently used" condition. My RCA BTA-250L transmitter started out as a second unit in a small station and was later sold to an even smaller station as their main transmitter. It was probably replaced before it had many miles on it.

Another reason for the high prices is a large number of collectors from overseas, especially the Far East. They are often willing to pay amounts that would make me blush. For some reason, Western Electric gear seems to be especially popular. I saw a WE 23-series console go for more than $10k :o to a collector in Japan. Yikes!

So, how would a tube audio console compare to the early famous Solid State consoles of the late 60's - 80's??
Tubes seemed well designed for nice quiet levels of hum and noise and probably better flatter freq response than the noisier solid state boards form the late 60's through 70's.
My memory of early solid state boards were high hum and noise levels and limited freq response. 50-15kc
The only advantage I pick up on with the solid state junk was that it ran cooler and could take the abuse of 24/7 rough handling. A little advantage would be the big DAVEN step rotary pots. But those contacts would fail from the constant barrage of cigarette smoke in the studio. They seemed well designed to work well without RFI issues even in the strong RF field of a typical AM transmitter site.
I bought a beautiful late 80's solid state console from our own Gary W2INR about 8 yrs ago. A Wheatstone TV audio console all solid state using the latest IC's of that time. Pure Class "A" audio. All strips check in with hum and noise in the 90's. Freq Response is FLAT!!! The VU meters never move, not even one increment, from 20-20kc. Awesome console. I use it weekly for my shortwave radio show on WBCQ. It's not wasted for ham radio AM. Strictly for my music show on WBCQ shortwave radio on Friday nights, 7490

Fred

I always regarded Wheatstone as the “Cadillac’ of audio boards, Gates (Harris) and RCA although RCA was just about thru in the seventies were good stuff and junk like LPB was crap in comparison. The Gates Radio Diplomat and Executive series of “Solidstatesman” radio consoles were everywhere back in the seventies and eighties and may have done more to replace all those old RCA, GE and Gates Yard consoles than anything else and I wasted many an hour cleaning the Daven pots on them. Also the positive ground and just plain weird bias systems used in that first generation transistor stuff was a huge pain to work on. Recall many hours wasted on the regulated power supply that had its pass transistor in series with the positive side of the bridge to ground. But the response and all the other audio aspects were good and would say that they were way better than the tube consoles that I came across back then. By the eighties most of the Gates stuff was being replaced by things like the Harris Medalist and despite the stupid wire terminations it’s a fairly good working board, the last two that I had worked with were ones I have taken out of service about three years ago I sold them in Dayton for $100 each with a ton of new spare part, documentation and cables and think they may have found their way into a LPFM station. They were in service for around twenty five years before I removed them.

My first paying job in broadcasting was holding down a board shift at our college radio station.  We had a beautiful Collins 212 series mono console.  I remember the big knobs on the faders, and how it felt like dialing a combination on a Mosler safe.  There were push buttons to the right of the VU meter, one of which was labeled "NEMO" for bringing in remotes, like basketball games.  Much later I would learn that "Nemo" was Telco talk for "Not Emanating From Main Office."

I really enjoyed your post. I wasn't sure where this post was leading. A report of fellow hams who have used the tube boards on the air and their radio experience or a little tech talk how the tube boards compared in sound quality and reliability on the air.
Fred

Hi Jim.

Here is a picture of one of those old Collins mono tube boxes. It is in daily service to this day.

I beat on broadcast gear from '64 on, retired some 5 years ago so I know your feelings.

I, however, always thought the good tube gear sounded better than the SS stuff.

Servicing SS gear was a lot more demanding than the tube models for me.  The inherent rejection of RF interference in tube gear was a unrecognized benefit until retrofitting SS gear.

The only real problem with hams using BC mixers today is they are 'backwards' for our purposes:  Many inputs, few outputs.

Many of us have several TX, so splitters or DA's come into play, and most of the input channels just sit and do nothing.

Yeah, I've seen many of them in hamshacks, working just fine.  Still....

I'm doing a restoration on a custom-built tube console from the old KHJ studios in LA.  It will be configured so the 6 channel faders control individual line-level outputs, with just two inputs.

73DG

Mike, that is exactly the board I was talking about!  Quality all the way.

Here's the big brother to Mike's 212B, the 212A two channel. Not a stereo board, merely more studio/remote flexibility and such for programming. Got most of the pieces to go with it, including the transmitter. Just stalled out in the 'time' dept.

I cut my teeth on a mono Gates Yard and an old 1960s RCA ( unknown model ) TV audio board.
Everything back then in TV was RCA ... cameras, switchers, video tape machines.  Antennas.

I put an RCA/Ampro stereo board in a 630 AM station's production room... Never could quite get the AM audio out of the board.  Took it to a 1550 AM and it played fine.  During a proof one night, I checked the frequency response and it was flat out to 40Khz or better.

My biggest audio board was a Ward Beck 48 channel stereo for the main TV news on-air control room.
It had six mix-minus busses with EQs on every channel.   Very intimidating for new trainees.
It would "audio-follow" the Grass Valley video board's inputs.

Mid-70's Ramco  capacitive "touch-pad" switching....

And Yes !!  I should have pre-wired the Harris Medalist to a remote terminal strip.

My last installs were Wheatstone R55 Analogs and so far, they have been bullet-proof.

Most small stations are going towards the Mackie or Behringer mixers. One for on-air and one on the shelf if the first fails.   Throw-away boards / Cheaper to replace than to repair.

The next series audio consoles will be all digital, but the listener will not notice the difference.

Don  ( mostly retired ) W4DNR   Huntsville Alabama

Don’t think the issues I had with tube stuff was at the top end, all that stuff was flat out to 20 KHz with no issues, I always thought the Tube stuff fell short on the low end with response dropping in the 20 to 40 Hz range because of the transformers and the like. Most of the DJs back then wanted lots of bottom end so it sounded like they had big balls, even the women but that’s all about processing. The thing about response is back in the time of the dinosaurs you had to do a yearly Proof of Performance for your AM station and amongst other things you had to demonstrate flat or nearly flat audio response from you studio chain and transmitter by inserting the audio generator at the microphone input in the studio and at 20%, 50% and 100% modulation from 20 Hz to 20 KHz show a somewhat flat response with low distortion. This usually involved wasting several nights after sign off trying to get all the junk to make spec before doing the test but being all of the equipment was built for broadcast would generally have no issues making that specification, after any necessary repairs. The problem was that you had to bypass all you’re processing when you did this because otherwise it would be cranking up the audio when you’re trying to do the 20 and 50 percent stuff. The last couple AM proofs I did back in the eighties degraded to the extent of just patching into the transmitters feed directly with the signal generator and bypassing the studio, processing and everything but that was just me being a slack jaw lazy kid. Imagine those old timey engineers did the signal generator input at the console microphone right up to the end. That along with daily base current readings (at the tower, not remotely) and reading there monitor points every week. Engineers must have had a lot more time back then.
 

That is a very sweet board.

Thanks. I hope I get it wired up and working before I'm too old to twist the pots.

Some irony and history behind that board. The irony - I bought it from a fellow here in NC in 2002 who had outbid me for one on ebay back in 1998. Just messaged him one day and we got to talking, he mentioned he had another board if I was interested. Bought it with a spare PS, had it shipped via Forward Air to Albany NY since I was living in VT at the time. Now I'm in NC and the board is maybe 2 hours from where I bought it.

The history - according to the seller, this was the board Jerry Falwell used when he was starting his radio career. It was also "used to record a number of bluegrass standards" back in the day. I need to get back to the seller to get more information, but it sounds like the board has had a colorful life overall.

Here's a shot of the accompanying bits for the 160 station. If there are no major faults found, it's probably a weekend job to get it all set up and tested. A number of little repairs needed on the transmitter but the parts are sitting here waiting.

Really nice setup. I love the old Collins BC transmitters and the way they put the show out front, so to speak. What's the point of running tubes (especially BIG tubes) if you can't see the glow? I love the art deco lines of my RCA xmtr, but the tubes are all hidden away in back where you can't see them. Except for the Collins badges on your stuff and the meatballs on mine, we have very similar setups. I'm living overseas right now but my plan is to also put my rig on 160 when I go home.

Todd, nice gear there, sonny!

             _-_-

14KB of visible whizzbang to show pictures. Sometimes there is going to be a problem when things get to that point. The link in that quote is apparently malformed as http://http//kwd-radio/WEB_files/welcome.html 

I'll try later on some other terminal as I'd like to see it eventually. Maybe IE will work, but it's pretty much Shields Up! and No! on this machine.

Universal fix for all web ailments:
If it doesn't work for me,
then I don't need to see,
and happy I will be,
when un-wasted time is free!

My vintage WECo 22D.

Dated 1943, from KCMO radio.

73DG

...want...

what toobes?
show us the back?

               _-_-

Here are some shots of the Collins 212B-2 I took in 2003. The lid lifts to get at the tubes. If you need to get to the underside of the modules you lift the front. It opens like a Buick front hood.

The three rack mount cabinets are (left to right) an unused transcription amp housing that now holds all of my PTT sequencing relays. Middle is the relay panel for the board. All original relays still working fine some 60 years old. On the right is the power supply. No porn for these. 8^)

Here are the last 2 pictures.

Gorgeous console Mike!    Glad your giving it a good home. 

73,
Joe-GMS

Sorry for the blurry pictures.

Mates with a BC-250GY

 Now the good stuff.

Ahhhh  :o

FINALLY YES!!! nice layout....that was hard work......hand wiring....Zenith always mad ea point of their TV sets were hand wired.

Thanks Mike
all of those DAVEN pots

I have a Dynamote that is virtually identical to yours. I got the original tweed case as well, although your case appears to be in a bit better shape than mine. The case came stuffed with all the cables and other paraphernalia, including headphones. One nice bonus--it also contained ALL the original sales paperwork, including manual, receipts, and even a factory QC check sheet. It was made and sold in 1946.

What do the outputs look like on them? I am going to assume that they are little mixers intended for live remotes. Back in the seventies and early eighties when I started in radio that’s how you did live remotes. We used Shure M-67 mixers that had two terminals on the back and you would call the phone company and set up a Dry Pair that was a signal pair with no voltage on it that would be connected to the remote location and terminated back at the station.  We had several dry pairs along with al the incoming phone lines tied back into engineering and all the dry pairs would show up on a patch field as just Tip and Ring and we would manually patch them thru to the studio that they were going to be used in. At the remote end there would just be a telephone line terminated into a block that we would attach to the mixer output directly. Because it was a balanced system and unless you had an issue with the phone line itself it all worked very well with good response and no hum, sometimes you would get a ground on the pair and when you did a test at the remote if that happened you would call the phone company and they would come and switch you to a different pair. And for all of this support by the phone company the station paid about only $6 per line to have it installed and operational for that remote. Back then engineers would go to the remote site and set everything up for the talent and also require at least one other engineer back at the studio for testing things from end to end. Once the phone company got out of the dry pair business we went to dial up remote mixers, small solid state mixers with a rotary dial or touch tone system or VHF/UHF remote Marti systems. Today most remote operations have migrated to digital systems that work across cell networks or TCP/IP systems that work over the internet.
Some of my first jobs in radio were setting up remotes and patching them thru back in engineering. The station that I was at back then had an Air, Interview, News and two production studios for the AM operation and a dinky little studio for there FM

I did some remotes for a college station in the 70's. I guess the M-67 were acceptable for the technology of that time to use for remote mixers, but I wouldn't be 10 feet near those things now. Shoved the audio down some pair of wires from the 'phone company. Really didn't sound that bad on the air. They switched the board to mono and no one knew the difference.

Fred