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Message |
    
Rficon
New member
Username: Rficon
Post Number: 6
Registered: 2-2005
| | Posted on Monday, February 14, 2005 - 9:51 pm: | 
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Hello,
What would be a better setup for this amp? 50 watts dead key, swinging to 300. Or 100 watt dead key, swinging to 350?
The meter I am using is not the greatest for PEP readings, although it has the switch on it. So I am assuming the 500v is putting out more. It is a radio shack meter(21-534), it measures dead key well though.
Any other advise as to the best dead key for this amp would be appreciated.
Thanks,
RFIcon |
Supertech1
Junior Member
Username: Supertech1
Post Number: 25
Registered: 1-2005
| | Posted on Monday, February 14, 2005 - 10:26 pm: |
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50 watt dk swingin' ta 350  |
Rficon
New member
Username: Rficon
Post Number: 8
Registered: 2-2005
| | Posted on Tuesday, February 15, 2005 - 10:11 pm: |
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Well,
I tried them both. My buddy who is 20 miles away, says that the 100 watt dead key makes me louder at that distance than the 50 watt dead key, even tough there is less swing.
With the 50 watt dead key, he said that my audio on his end was fluctuating up and down, and with the 100 watt dead key the audio was solid. Whatever that means.
Would leaving the AM dead key at 100 be OK?
Thanks,
RFIcon |
Audiophile73
Member
Username: Audiophile73
Post Number: 53
Registered: 5-2004
| | Posted on Wednesday, February 16, 2005 - 4:48 am: |
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That is a good amp. The 2879 transistors I like because they can take a little more abuse than others. 350 watts is low for that amp. you should be able to get anywhere from 400 to 500 watts out of that amp. Texas star says with a 4 watt input you will give you 250 watts, so i would dead key 4 watts into that amp. It's a big amp it can take it. Then fully modulated you will be at about 500 watts. Don' listen to these people that say snip this solder this. Then you will just have a radio that hardley keys at all and swings like crazy, that equals a overmodulated crappy signal. Dead key 4 watts let is swing. Make sure your power cable for the amp can handle about 45 amps of currrent. This will probably be 6 or 4 gauge. Wire it to the frame. The shorter the ground the better remember that. Use a thick ground like 4 gauge. Also make sure your battery has a good ground i would suggest 4 gauge for this to. Sorry for the long post, let me know how everything works out. |
Tech808
Moderator
Username: Tech808
Post Number: 4871
Registered: 8-2002
| | Posted on Wednesday, February 16, 2005 - 11:14 am: |
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Rficon,
Check out the Link below:
EX 500V
With the EX500 and EX500V you are looking at Approx. Power Output with 20 watts input of 500 watts and 45 amps.
Hope this helps,
Lon
Tech808
CEF808
N9OSN |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 459
Registered: 7-2004
| | Posted on Wednesday, February 16, 2005 - 5:24 pm: |
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always ran 667v @ over 200w dead key & about 300w rms swing, dual fans kept heat lower, no fans burnt paint off resistors & curled some of the bare jumpers. 500 should still be fine with 150w dead key, add fans if it makes you feel better-amp will. when you start running 'touchy' setups, or really want to adjust properly, a good wattmeter is a must. |
Rficon
New member
Username: Rficon
Post Number: 9
Registered: 2-2005
| | Posted on Thursday, February 17, 2005 - 11:44 pm: |
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OK,
250 watt dead key, isn't that a little high for a 500 watt amp?
I was always thought that you wanted a 1:4 carrier to peak ratio. And it was best to set it 1:4.5 with a loud tone(aaaaauuuddiiiooo), because your voice will never modulate that high during normal speech. And if you wanted a little extra loudness without a noticeable increase in distortion you could set it at a 1:5 ratio, but anything over that and distortion takes over. Is this not true?
After I obtained a more accurate meter, I measured my PEP at 450. Adhering to the 1:4 ratio I tried a dead key of 112.5(well, as close as I could get it.), on air reports were positive.
Next I tried a 1:4.5 ratio, which is a 100 watt dead key. By the on air accounts the change in dead key was not noticeable.
For testings sake, I also tried the 1:5 carrier to peak ratio. With a 90 watt dead key. On air accounts say it is a little louder and no detectable distortion.
As far as the 50 watt dead key. Distant stations say that the peaks of my audio are clear but the low end modulation is not near as loud as the high end, causing the rapid fading in and out.
Am I understanding carrier to peak ratios correctly? If so, why does Texas Star suggest a 1:2 ratio?
Thanks,
RFIcon
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Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 462
Registered: 7-2004
| | Posted on Friday, February 18, 2005 - 6:11 pm: |
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adjust it to where you get the best signal reports. the 4 2879's should be able to provide 240 watts out with no problems. swing is limited by the design & components of the TS to 480 watts, give or take a few. wherever the best signal reports are with dead key under 240 and heat kept to a minimum(with the use of fans if need be) is acceptable.
90-100-112.5 watts dead key shouldn't show any difference in signal strength.240 watts dead key could get you another S-unit. at some point, as the dead key goes up the swing will not be as much. if it dead keys 240 & swings 300, then it is too much, if it dead keys 240 & still swings 450, as long as it doesn't overheat you can use it. see how your on air reports are. they say 'swing is king' but the dead key is where most of your power is.
"limited by design & components", no 1:4 out of my 667 was possible with 200+ watt dead key. my davemade m400, same transistor compliment will do 1:4 with almost 200 watts dead key. max input amp can handle, max output of amps with no heat & shoot for the best signal report & let the chips fall where they may.
& if that ain't enough, we buy a bigger amp! |
Wolverine
Intermediate Member
Username: Wolverine
Post Number: 320
Registered: 2-2003
| | Posted on Saturday, February 19, 2005 - 4:04 am: |
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Also in some cases, some radio operators prefer to use (With a 4x 2879 amp)a 1:3 carrier to peak ratio, using single or dual final radios to offset the low end modulation problems because of a lower dead key. In skipland, audio makes your heard, but a good carrier takes out the ducks.
Wolverine. |
Wolverine
Intermediate Member
Username: Wolverine
Post Number: 321
Registered: 2-2003
| | Posted on Saturday, February 19, 2005 - 4:11 am: |
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Btw, in my last post I was refering to fan-cooled, custom or competition amps, like the 4 pill Davemade, X or Magna-force, Skullcracka, etc. I never did prefer Texas stars, because of the problems with the keying relays, design components, and poor heat disapation.
Wolverine. |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 464
Registered: 7-2004
| | Posted on Saturday, February 19, 2005 - 2:54 pm: |
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never had any problems with texas star, though they do require you to pamper them a bit more then the customs. still have a 350 & 1600, both from 1990 or so, my old 667 is still in somebody's truck locally, from 1988 or so, early 90's 500 is still mobiling here. very reliable, i think, if you treat 'em good. 2 big fans screwed to the cooling fins helps, too. of course my davemade m400 runs right up there with texas star dx1200's.... |
Rficon
Junior Member
Username: Rficon
Post Number: 13
Registered: 2-2005
| | Posted on Saturday, February 19, 2005 - 3:32 pm: |
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OK,
Since I don't have any fans(and would prefer not to), I am going to try 150 watts for a dead key. Should I be OK with heat at this setting?
Is 200 dead key too high without the use of fans? I dont want to burn up anything inside.
I always thought that the perfect AM wave was a 1:4 ratio, but from what I am reading, it looks like the higher dead key is better. I was under the impression that a 1:2 or 1:3 ratio would make you sound "pinched up" and not allow for 100% modulation. I guess my info was bad.
Thanks,
RFIcon |
Racer_x
Junior Member
Username: Racer_x
Post Number: 13
Registered: 2-2005
| | Posted on Saturday, February 19, 2005 - 8:31 pm: |
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RFIcon - You're right in that a perfectly symetrical standard AM signal at 100% modulation will show a 4:1 ratio of carrier to peak envelope power. Here's a website that explains it for amateurs with theory and some math:
http://www.qsl.net/wa5bxo/amplitude-modulation-and%20pep.htm |
Wolverine
Intermediate Member
Username: Wolverine
Post Number: 322
Registered: 2-2003
| | Posted on Monday, February 21, 2005 - 2:53 am: |
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1:4 carrier to peak is preferable. Depending on the amp, you can get by with the 1:3 carrier to peak for more "Punch". 1:2 carrier to peak ratio will definitely cut your swing wattage, making you sound muffled, pinched, etc. I very much enjoyed that link Racer X. Kudo's to you.
Wolverine. |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 471
Registered: 7-2004
| | Posted on Monday, February 21, 2005 - 9:44 pm: |
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who said 'tune for maximum smoke'?
well that's what we did. it was cool. left the windows open to clear out the smell. 8" of snow. then a bunch of rain. smell's gone. gotta dry out the interior now. yes you can blow up a texas star dx500v. it apparently doesn't handle as much input as the old dx500hdv. while listening to the silence/occasional spanish and calling during the quiet sunday net a buddy found my spot at the beach. his bladerunner-modified ancient messenger 3kw with the brand new dx500v driver needed a check as his autek wattmeter wasn't up to the task. apparently neither was my diamond sx100. one 2kw deadkey & the sx100 coughed & sputtered. not sure why, there was no modulation, but needle went just past 2kw, then swung wildly back & forth. unkeyed, repeated & same thing happened. checked dx500 & got nothing, but dx came back. ok. put autek back in line & dx500 was dead keying 200 again. must have smoked the diamond.put it back in my truck, after about an hour & it appeared to be working. reflected was a bit high though. checked the grant xl, dead key wasn't right. & it wasn't varying as it should. unplugged the low drive davemade & plugged in the texas star. no swing in pep, no more movement then in avg. checked xl, keying less then 1 watt, swing 1.5. opened it up, on the beach in the cold & adjusted the am power vr all the way up. still only said 2 watts. with dx500 on, over 400 watts dead key now, swing to 420. then the fun began. the rancid smell of 10 ohm smoke. the popping of electrolytic capacitors. unkeying the mic & everything staying keyed only increases the smoke. i've always said blowing things up isn't a big deal. it wasn't this time either til i realized the texas star was now on fire & i had to get it out of the truck before it too went up.
the texas star is trash. the diamond wattmeter apparently couldn't handle the 2kw dead key on 18 volts & rf arcing shorted it out. when it cooled it spaced far enough apart to work-inaccurately however. the dx500 warmed it up enough to cause arcing & shorted it out again, so my 2 watt dead key from the grant was closer to 7. that should not have been enough to show 400 watts dead key from the dx500, & still not sure why sx100 even showed that. doesn't matter now, doesn't show anything pep, avg isn't right either, ar3500 is keying 5 swinging 20 on it, but on pep bird is keying 35 & swinging 150+. grant not working at this point either. it was set right when it read less then 1 watt output, cranking up the npcrc& volted final smoked it, too. was gonna mod my grant lt, but since xlowners club website is no more, spent HOURS online before i found the mods i was looking for on another forum. so i just replaced the 2166 & 1969 with ones i pulled from a junked 148. now i just gotta tweak & fine tune it because it's not quite the same sound as before. but as they say, close enough for government work.
i'm not sure what caused the texas star to fry. the xl dead key should not have done that on a couple of keys & swing was only in the 20's. only thing i can figure was sx100 shorted& reflected most of the excessive carrier back into the texas star & POOF! the OLD dx500HDV, which is different from the new 500 & 500v handled MUCH more wattage then that. oh well, you learn something every day.
so, yes wolverine, i agree with you, depending on the amp, you can go 1:3 or even a bit more. but 1:1.05 carrier to peak on the new dx500v really SMOKES!
by the way, the messenger driven by my davemade & repaired xl works fine after all, my &^%$#@ old maco wattmeter shows 2400 watts dead key & pegs the 4000 watt scale on swing. yea, right. not accurate, but at least we know everything works. |
Wolverine
Intermediate Member
Username: Wolverine
Post Number: 323
Registered: 2-2003
| | Posted on Tuesday, February 22, 2005 - 5:32 am: |
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Patzerozero, what's the difference between the old dx500HDV and the new 500v, besides being able to take more wattage? I thought that the guts of both amps were virtually the same?. You definetely do know how take experimentation to the extreme, I'll give you that. But..... learning makes it worthwhile. As the Capital One cliche goes, "What's in your wallet?".
Wolverine. |
Wolverine
Intermediate Member
Username: Wolverine
Post Number: 324
Registered: 2-2003
| | Posted on Thursday, February 24, 2005 - 5:17 am: |
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Okay Patzerozero, I see you haven't log in since 2/21/05. So Rficon, the best way I can compare the carrier to peak ratio, is by using the analogy of torque vs horse power in racing engines. Many feel that torque is king, but others feel that horspower rules. Horsepower will get you down the track, but many engines aren't happy running at high rpms. Merely considering peak numbers can be misleading. You don't want to base your performance on a peaky curve, it's better to pick up the average (Carrier) for superior performance. In amplifiers, everything is basically trade offs deciding, between average (carrier) and peaks. Most in racing, build for torque, feeling that after that, the horsepower will take care of itself. In amps, the 1:4 carrier to peak ratio is a good compromise, that's how I run mine. If I want to pick up the torque in my amp, or should I say my average carrier for staying power, the 1:3 carrier to peak ratio is the max that I would use. Others prefer to "Maul" their amps with a 7 to 10 watt dead key. In the case of Mauling amps, they are gaining or picking up an increase (Carrier/Torque), but they are losing power somewhere else (Modulation peaks/horsepower). Remember you can't have horsepower without torque, but you can have torque with out horsepower. It's called a "Dump Truck". Hope this helps.
Wolverine. |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 482
Registered: 7-2004
| | Posted on Friday, February 25, 2005 - 1:49 pm: |
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your last post has it about covered, wolverine, good comparison.
took a quickie get-a-way with wife & kids to amish country in PA, had to out race the snowstorm last nite to get home. last 1 hour of drive took better then 2-oh well.
wife got into truck about midnite monday nite & said-'YUK! what IS that smell?' well i thought it was gone.
buddy got his replacement 500v-texas star apparently no longer has an HDV model. from looking at the insides of these 2 side by side, the 500HDV uses BIGGER everything. tiny resistors, tiny caps, even the wire leading from both SO239's to the board is a VERY thin piece of UNshielded wire on the new 500v. the 15+ year old HDV uses a piece of rg58 from the SO239's to the board. the boards are the same, the values are close, but the older 1 uses bigger combiner & transformer forms & wire, as well as 25 & 50 volt elctrolytics, not the tiny ones in the new amp, same with resistors. i think some of the changes at 'xmtr' SO239 were the high drive difference. looking at texas stars website, they say 4 watt drive for the 500 & 500v, the 500hdv was stated as 10 watts drive in print(back in the pre-internet era).
"swing is KING-but dead key RULES", ya just gotta know when to stop! |
Wolverine
Intermediate Member
Username: Wolverine
Post Number: 328
Registered: 2-2003
| | Posted on Tuesday, March 01, 2005 - 4:55 am: |
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Thanks for explaining the differences, Patzerozero. |
Hotwire
Intermediate Member
Username: Hotwire
Post Number: 139
Registered: 1-2005
| | Posted on Tuesday, March 01, 2005 - 10:30 am: |
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Speaking of Texas Stars.....Is the qaulity of these amps diminishing? Years ago my dad always used them and handed some down to me. They were by far the best in my opinion. Do all the new Tex Star amps use cheaper stuff inside now? I ask because I'm getting ready to buy a 667, I dont want to just buy the name!
Hey Patzerozero, you are a believer in Texas Star. You smoked your 500V right? Would you buy another just like it? I'm going to lay down some big bills on a linear and need it to last a long time. Starts getting to expensive when big amps start smokin. |
Topten
Intermediate Member
Username: Topten
Post Number: 196
Registered: 9-2002
| | Posted on Wednesday, March 02, 2005 - 11:37 am: |
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Just got a Texas Star 500-V a few weeks back. It sure seems to me that the quality is still there. These amps are a just a clean & simple class AB1 design. As long as they are not overdriven, over heated, or over volted (14 volts max) they should last and be trouble free for many years.
Alas, many folks in my neck of the woods prefer those home made style class C amps that they can run up to 19 volts that bleed and splatter harmonics up to 10 channels above and below the channel they are talking on. Not to mention that they also cut their audio limiters, crank up their radios to the max, use power mics & echo, it's just plain awful, they sound so bad & distorted that it causes me pain just to hear'em as I'm passing through scanning the bands.  |
Rficon
Junior Member
Username: Rficon
Post Number: 24
Registered: 2-2005
| | Posted on Thursday, March 03, 2005 - 3:39 am: |
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Well,
After using different settings, I have settled on 100 watt carrier out of this amp swinging 400+. It seems to run cool and reports are good.
I was on my 2950DX 1.5 watt dead key swinging to 15 watts(limiter intact, no swing mods, modulation at 98%) in to the 500V on channel 15, when a friend from 6 came up to tell me I was bleeding. He was about a 1 1/2 miles away. I figure that it was because I was so close to his base.
I dont think that I am over driving the 500V in any way. All of my Palomars and Galaxy's that I owned in the past were splatter boxes, just at half the advertised power. lol. I think the TS is cleaner, but when you get that close to someone with that kind of power, bleed will happen. Even with the best ham amps.
Over all this is one of the best amps that I have owned. It's power is very close to what it is rated at. The construction is very solid. And the audio is very clean. A little splatter when you get close to it, but every amp does.
later,
RFIcon
P.S. Topten, what carrier are you running out of your 500V? What is you PEP? |
Topten
Intermediate Member
Username: Topten
Post Number: 197
Registered: 9-2002
| | Posted on Friday, March 04, 2005 - 2:50 am: |
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Radio = 2 watt dead key with a swing up to 15 watts. TS 500-V = 10 watt dead key swinging up 100+ watts with auuuuddddiiioooooo said into the mic. Regular talk is between 40 and 50 watts nominal or RMS. But with a simple twist of the V knob, activating the Top Gun on my S-45, and with all that going through my I-Maxx 2K w/GPK it just lights up the sky. |
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