Easiest way to achieve hi fi?

[Sonar]

Oh good god...I'm not a disc jockey....lmao...they don't make Dave made transmiters anymore do they? And the w2hiy is hardly worth that kind of money..maybe at the end of the day a Turner +3 is the way to go with a touch of echo on a connex board ...I just want to get away from the pinched tinny sound ....why talk on a trashy sounding radio..don't we strive to sound good over the air?? Good points sonar...if I could get a valiant I would.

Captain Kilowatt often mentions his modified Heathkit dx transmitter. I'd love to hear that thing. Those dx model Heathkit transmitters are common on eBay. Even the 35 watt ef Johnson ranger with it's 35 watt output will sound excellent. Those transmitters can be purchased in restored condition ready to go or on the cheap if you know how to restore it. 73

 

[Bearcat]

Captain Kilowatt often mentions his modified Heathkit dx transmitter. I'd love to hear that thing. Those dx model Heathkit transmitters are common on eBay. Even the 35 watt ef Johnson ranger with it's 35 watt output will sound excellent. Those transmitters can be purchased in restored condition ready to go or on the cheap if you know how to restore it. 73

Those anchors sound awesome

 

[Bearcat]

Captain Kilowatt often mentions his modified Heathkit dx transmitter. I'd love to hear that thing. Those dx model Heathkit transmitters are common on eBay. Even the 35 watt ef Johnson ranger with it's 35 watt output will sound excellent. Those transmitters can be purchased in restored condition ready to go or on the cheap if you know how to restore it. 73

Would the white face johnsons fit in this catagory? Or no?

 

[Robb]

I agree but only up to 150% modulation, they sound close!

I think this is the video? At 200% modulation (i.m.o.) the direct inject audio sounds too distorted compared to the MMM board at 200%.

So that is Stickman. Looked at a couple of his videos; seems to be up to his @zz in alligators. Has too much work to do. Eight months of wait time - sounds like he cannot catch up. Happens to the better techs - getting swamped - that is . . .

 

[Bearcat]

So that is Stickman. Looked at a couple of his videos; seems to be up to his @zz in alligators. Has too much work to do. Eight months of wait time - sounds like he cannot catch up. Happens to the better techs - getting swamped - that is . . .

Sheez it sounds good both ways

 

[543_Dallas]

Cool, thanks for the clarification. Makes much more sense now.

My appologies for asking so many questions but I do have one more about a post here on the forum about a conversion to low-level am on a cobra 2000 witch I understand is basically the same radio..worth investigating or no?

Ill shut and read more now...


Peace to all

Id just start out with a low level rig. Seems like more trouble than its worth. A ts440 is a better candidate for this if you use external audio gear. Pipe the rack gear into the balanced modulator, replace the 455 filter and adjust the alc. It takes more work than a 148, less work than a boat anchor and performs better than both.

HiFi on AM is a misleading acronym. True HiFi is normally associated with FM, but If you wanna sound like 131 Mustang get yourself one of those Dave Made transmitters he's operating. I'm not familiar with the setup of the DM transmitter but short of a good mic you're probably gonna be good to go. You could get yourself a nice valiant for between $400 and $800. Actually any later 1950's AM transmitter will have you sounding exceptional on AM. Essb is a different monster and much easier to get any of the big three company transceivers sounding excellent. After purchase Kenwood ect ect buy yourself a W2HIY 8 band eq, eq+ or both and with a little listening and reports you'll be in business. There's other ways of doing it but like many said it's a learning curve, and IMO a mess of wires, lots of money not well spent only to realize HiFi AM is actually widebanding on AM. I've come to enjoy and appreciate my slightly modded sonar fs 2340 (bypassed audio clipper board) driving a phantom (11/2 watts dk 18 pep) and demco modulator. That's just me of course and everybody has to meet their own expectations and dreams of what they want their stations to sound like. Good luck. Ps Whatever you wind up doing please don't hang out on channel 28 (AM) and take song requests (no name's mentioned). 73

Tube equipment and spending too much money on old junk isn't the only way to get good AM. Yes the old rigs can sound good on AM but without some major work they will not have the bandwidth they're after. WA1HLR did some good articles on the old AM rigs. There are exports out there that sound better with a d104 than a stock Valliant...and they have a built in receiver.

Unless your into vintage gear and enjoy working on them these old rigs are a bad choice. Most of the guys so quick to recommend these old transmitters wouldn't use the thing if they had it.

[QUOTE="543_Dallas, post: 564156, member: 21044"
Since you are modulating the finals in the radio there is no input and output of an amplifier to compare. If it were a low level modulated rig or if you wanted to see how linear your amplifier is use the trapezoid test.

Not necessarily. While a trapezoidal test does show linearity it is also useful for measuring the modulation of an RF envelope.

http://www.radiomagonline.com/misc/0082/measuring-modulation/26624
https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0ahUKEwjA5vXI2rLPAhXB6SYKHQCPA9AQFgg9MAU&url=http://preciserf.com/wp-content/uploads/2012/03/Appnote-1-Trapezoid-test2.pdf&usg=AFQjCNHI-rT0AE66AyKNnuSYu2C9XIodEw&sig2=uSbNprSFnliy7YTcEqSfxA&cad=rja[/QUOTE]

When dealing with a collector modulated transmitter where precise modation measurements are not critical doea the trapezoidal test tell us anything we can't see by looking at the waveform?

 

[LeapFrog]

That's it. Look at D8 in a cobra 29. That's the first diode so you'll only need 2 more.

I currently have a TIP120 variable carrier control I Installed in the 25, I can adjust the carrier down to 1/2 watt and still get near max "swing" out of it, I need to modify the AMC because with the VR all the way counter clockwise I still have a pinched carrier (due to neg. peaks crashing) at times with mic gain all the way up, I believe I have exceeded 200% Modulation on a Cobra 25/29 by reducing the carrier, with faults..
I would love some suggestions on keeping the AMC active enough to put the neg. peaks anywhere between 95%-99% while the pos. peaks happily reach 120%-160%.

In the past (before I got the o'scope) I have added two diodes to D8 and it reduced the carrier, but for every diode inline that's additional 0.7V lost and I already run @ 12 Volts so dropping the voltage further may be troublesome, perhaps when I get a nice power supply (@13.8v) I will revisit the idea.


EDIT: I may do some more testing and just start a new thread on the topic of transformer modulated AM only radios exceeding 125% modulation.
Thank You
-Leap

 

[Captain Kilowatt]

When dealing with a collector modulated transmitter where precise modation measurements are not critical doea the trapezoidal test tell us anything we can't see by looking at the waveform?

Collector modulated, grid modulated or plate modulated is irrelevant as to the requirement of precision measurements being made. A trapezoidal waveform can be used to measure modulation percentage just as well as a sinusoidal waveform especially when it comes to overmodulation. You just need to know what to look for since the two techniques are different.

 

[Captain Kilowatt]

Captain Kilowatt often mentions his modified Heathkit dx transmitter. I'd love to hear that thing. Those dx model Heathkit transmitters are common on eBay. Even the 35 watt ef Johnson ranger with it's 35 watt output will sound excellent. Those transmitters can be purchased in restored condition ready to go or on the cheap if you know how to restore it. 73

I'd like to hear it on the air sometime soon too. It is presently disconnected but I think sometime in the next few weeks it may get hooked back up and put back on the air. I just have had no time for anything this past year.

 

[543_Dallas]

Collector modulated, grid modulated or plate modulated is irrelevant as to the requirement of precision measurements being made. A trapezoidal waveform can be used to measure modulation percentage just as well as a sinusoidal waveform especially when it comes to overmodulation. You just need to know what to look for since the two techniques are different.

Gotcha. The reason I said collector modulated is because sixstrings was asking about a trapezoidal test for linearity and I didn't think that really applied to a high level transmitter.

We're getting into a grey area where I don't have a lot of experience so I was asking you to check my math.

 

[Captain Kilowatt]

We're getting into a grey area where I don't have a lot of experience so I was asking you to check my math.

Hey even I have been known to misplace a decimal point now and then.

 

[StrangeBrew]

Hey even I have been known to misplace a decimal point now and then.

Here's some extras, save them for when you misplace another.

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[Mustang 131]

Love it when I play some deep bass on my Ranger and modulation tranformer shakes the table. Real old school feel and smells..
FYI the Dave never stopped making the xmitter or hifi 148's...or anything else. But good luck getting one.

 

[Bearcat]

Love it when I play some deep bass on my Ranger and modulation tranformer shakes the table. Real old school feel and smells..
FYI the Dave never stopped making the xmitter or hifi 148's...or anything else. But good luck getting one.

Why so hard to get one?

 

[BBB]

Why so hard to get one?