Drake stuff...

[N2DTS]

Noticed a glut of Drake stuff on epay lately, nice looking stuff cheap.
How did they do their AM?
Screen, or in a balanced modulator setup?

TR4 had three TV sweep tubes in the output?
Can they sound good?

[nq5t]

Noticed a glut of Drake stuff on epay lately, nice looking stuff cheap.
How did they do their AM?
Screen, or in a balanced modulator setup?

The TR3/TR4 radios screen modulate the finals.  The T-4X radios screen modulate the driver tube.

I have no clue how good or not they play, although there are some mods around to "improve" things.

Grant/NQ5T

[WQ9E]

Drake tube type gear (4 line transmitters plus TR3,4,6 but not the later solid state 5 and 7 line) are controlled carrier with screen modulation (driver is modulated in the T-4X line).  They can sound very good but some people get bent out of shape because the carrier level, and thus the receiver S meter, will vary much like a SSB signal and as the power drops between words the controlled carrier AM signal won't "quiet" a noisy band.

I have worked a lot of people who regularly use Drake 4 line transmitters on AM and they sound good.  Controlled carrier transmitters work extremely well with SSB linear amps and most amps can be run at or very close to their SSB power rating unlike when using full carrier AM.

Although not favored by the "hi fi" audio crowd the 4 line receivers were some of the best performing vintage receivers and a Drake C line remains my favorite low band CW setup.

[W2NBC]

Simple modifications here:
 
http://www.amwindow.org/tech/htm/t4.htm

Proof? Listen to WD8BIL:

http://dl.dropbox.com/u/17340243/WD8BIL.mp3

Quality gear..

[Pete, WA2CWA]

I had a "B" line", "C line", and 3 TR-6's. Never liked the quality of AM on any of them. Also, never cared for the audio quality on SSB either with its very punchy/space shuttle audio. Got rid of them all. I'm not a fan of sweep tubes either.

[Jim, W5JO]

Much of the sound depends on your receiver.  If the controlled carrier pumps the AGC in your receiver, they will tire you.

I don't mind them for about 20 minutes.  They are good to drive an amplifier if you set it up correctly.

[W2JBL]

    I have a Drake 4 Line, a TR-4CW and a TR-3. All are excellent on AM with simple mods. In the TR3/4 radios simply use the DX60 screen modulator with variable carrier level posted on this site or amwindow.org. The result is up to 40 watts carrier with tons of headroom and outstanding fidelity. On the TR-4CW I removed the CW filter and replaced it with a 6kc 9MHZ filter form INRAD (was for a Yayzoo FT301). This made it a very capable 40 watt AM transciever. Simple mods to the first speech stages also help a bit on SSB with the audio. The T-4/T-4XB/T4XC rigs use a mod I developed and was posted by K1JJ on amwindow.org or here, I forget. That one gives about 25 watts carrier also with excellent fidelity and headroom. Bud WD8BIL is using a T-4XBwith that mod and sounds just like he does on his plate modulated rig. The audio in the receivers can be easily improved, and if tuned offset to copy one sideband sound pretty good.

[K1JJ]

Yes, the T4-X Drake transmitters sound as good as any top notch AM rig once modified like Bud's rig.  Simple to do.

I really like the look and feel of Drake gear. Cult status.  It's just one step below the Collins S-line in quality. They come from an era at the peak of tube technology. Easy to work on and lightweight.

At one time I had the T4XC and R4C rigs. Mint.  Sherwood mods and JBL AM mods. The receiver is FB for DX.  Widen out the R-4 I.F. and come off the detector and it sounds hi-fi on AM.

Highly recommended for a hands-on tube experience.

(Now if we can just get Jeff to finish up his new big mawls and get on the air....  )

T

[VE3AJM]

Screen modulation with good efficiency and punch!! So you don't have to try and re invent the wheel after all. The Drake gear has been around for 50 years.

Al VE3AJM

[N2DTS]

I had an R4c a while ago an thought it was great, but to narrow in stock form for AM really.
A crazy mix of solid state and tubes, really crazy with ic chips in the cathodes of tubes and so on, but very well made with a quality feel.
With prices so low on ebay, $200 to $300 for many radios, it seems like a very good deal for a tube radio project.
More power out then a dx60 with a receiver built into a smaller package, and a VFO?
I am starting to really like screen modulation, 40 watts carrier is ok for 40 meters and up...

[WD8BIL]

The mods on the T4X only took an hour or so to do. Well worth the time considering the vast improvements. High class audio with no controlled carrier.
I out boarded a pot to set the carrier level as it does change a wee bit with band changes. But it does drive the amp nicely!

[N2DTS]

There was one on ebay for $125.00, no power supply I guess but I have one of those.
Very tempting..

[Todd, KA1KAQ]

Yep, out of the box the Drake stuff sounds pretty lame on AM, but we need to remember that it wasn't designed with AM as a primary mode to start with. And as Buddly has shown, transmitted AM can be improved greatly with a minimal amount of work.

I've said for years that Drake gear is by far the best deal out there in the BA world. They used later vacuum tube designs, built the equipment well, priced it right and sold a lot of it. My only gripe has already been mentioned by Pete - sweep tubes. At the time it made good economic as they were plentiful and cheap. That changed pretty quickly.

The power supply/speakers come up fairly often in the $100-$150 range.

[W8EJO]

Does anyone know whether the AM Window mod applies to both the T4X and the TR3/4 or is it strickly for the T4X?

[WD8BIL]

Looking at the TR4 schematic I don't see why these mods wouldn't work. The V14 AM modulator is a dual triode but the nature of the mods should be applicable. I'd start with adding an audio input to the grid of the first triode and feeding it with out board audio. The controlled carrier will probably still be there but it would definitely improve the audio over the stock mic preamp.

[W2JBL]

In my TR3 and TR4CW I used the DX60 screen modulator circuit with variable carrier level posted either here or on amwindow.org The rigs use the same tube-
a 13DE7 for the modulator so it was easy. I also changed coupling and bypass caps in the speech amp, otherwise the audio would still be  restricted. You get up to 40 watts carrier when you do this, and it works great.

[N2DTS]

Is one better then the other for any reason?
(TR3-TR4CW)

In my TR3 and TR4CW I used the DX60 screen modulator circuit with variable carrier level posted either here or on amwindow.org The rigs use the same tube-
a 13DE7 for the modulator so it was easy. I also changed coupling and bypass caps in the speech amp, otherwise the audio would still be  restricted. You get up to 40 watts carrier when you do this, and it works great.

[ka1bwo]

I have the original Drake

[Steve - K4HX]

https://www.youtube.com/watch?v=4ZU05h3U2Hw

[K1JJ]

He was a sharp dresser.

[W3GMS]

A lot has been written about the founder of Drake and in reading the history he was certainly a very capable engineer and also knew how to build a successful company.  I have a lot of their products and its all outstanding equipment. When properly modified the gear sounds fantastic on AM.   

The book, A Family Affair - The R.L. Drake story, was enjoyable reading.  I also found a lot of great information about the history of the company on the internet.   

Here is a photo of R.L. Drake himself!     

Joe, GMS

[W8EJO]

What would be a good, inexpensive mic/preamp/equalizer combo for the K1JJ modded T4X?

I have Shure 444's, D104's & a EV664.

[WD8BIL]

TERRY,

I guess the best place to start would be the pre-amp. You'll need line level to drive the T4X after the modification. I use a small Behringer MX602A mixer. But any line level output should work well.

Once you decide that I like the looks of the 664!!!! I have the Lafayette version of it and it works well in this setup.

I don't remember ever hearing anyone using a D104 into a mixer. But, it could be done I guess.
 

[W8EJO]

Thanks Bud. I'll look for one of those Behringer MX602A mixers.

55 years of ham'n & never had any outboard audio gear.