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Message |
    
Bluebird
| | Posted on Sunday, February 15, 2004 - 3:59 pm: | 
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how much power can i get out of a texas star dx 250? and how can i filter this amp the best, A REAL SPLATERY AMP |
Audiophile73
Member
Username: Audiophile73
Post Number: 55
Registered: 5-2004
| | Posted on Wednesday, February 16, 2005 - 5:03 am: |
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of course its a splattery amp its a cb amp. Some people say those are ham amps. There not, they are sold as morse code transmitters to be legal then coverted for a cb amp. They are dirty. Dead key 3 or 4 watts and let it swing from there. youl get anywhere from 180 to a little over 200. But you'll probably never see 250 unless you slam it. A 2290 is rated at 60, but the most i've seen a 2290 do is 90. Unless you volt the daylights out of it. But then it aint gonna last very long |
Musket
New member
Username: Musket
Post Number: 1
Registered: 12-2004
| | Posted on Thursday, March 17, 2005 - 4:08 pm: |
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I have a DX-250 4-button with 2 455 pills , being pushed by a cobra 148-GTL 5 pin side mike ,radio dead keys 4.5 watts am. , swings 15 .On ssb swings 20+ .. AMP on low am.70 med. 125, med. high,180 onhigh 240. SSB. amp on ssb mode swings about 250. Amp is manufactured 1983 has windings no crystals swr about 1.4 to 2.o depending on power settings. I know radio is pushing it to hard ,amp works best on med. power setting swings to about 200 on am. |
Patzerozero
Advanced Member
Username: Patzerozero
Post Number: 575
Registered: 7-2004
| | Posted on Friday, March 18, 2005 - 6:55 pm: |
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250 watts with 2-455's? wow that's a lot. my early '80's dx250 has 2290's & keys up to 60 watts with 160 or so swing. |
Inspector
Intermediate Member
Username: Inspector
Post Number: 140
Registered: 12-2001
| | Posted on Friday, March 18, 2005 - 8:31 pm: |
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WOW!...455s from 1983!...You're lucky they haven't blown yet. To save the amp from over-heating and blowing the pills, lower the dead-key of the radio to about 2 to three Watts...and if it swings, all the better, just don't over do it. I was wondering what you meant by crystals and then I realized you were refering to Audiophile73s post...only lately did TS add a crystal oscillator to the amps, to attempt to sell them legally as a transmitter. New or old, when working as an amp, there should be NO crystal in the TS units. As far as filtering, I would put a low-pass-filter between the radio and the amp AND one between the amp and the antenna...If that don't clean up a signal, nothing will! |
Musket
New member
Username: Musket
Post Number: 5
Registered: 12-2004
| | Posted on Wednesday, March 23, 2005 - 6:04 pm: |
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455s from 1983 ! They have blown couple years ago with a bad power supply 1 of the 4 mounted resisters on the back of the 20 amp pryamid gave out and thing was doing 24 volts instead of 13.8 took the amps 455s and baked them.. I turned down the radio to 3watts and it swings to about 10 now on am . amp on high does about 225 now but rf meter swings back wards on amp?? |
Patzerozero
Advanced Member
Username: Patzerozero
Post Number: 610
Registered: 7-2004
| | Posted on Friday, March 25, 2005 - 7:33 pm: |
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gotta check it on an external wattmeter. if it's swinging backwards, it's probably being overdriven, both dead key & swing input. those 2 455's should not be doing any more then 125 watts.
(you sure it's not 454's? they're rated 80w, same as 2290's, but still should be in the 150 range or so. also have to make sure you're reading on the wattmeters lowest scale without full deflection. 200w on the 300w scale of my old diamond showed WAY more when read on the 3kw scale. but that's not right) |
Musket
New member
Username: Musket
Post Number: 6
Registered: 12-2004
| | Posted on Monday, March 28, 2005 - 9:22 am: |
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readings are off a pdc 600 meter, at 1000 watt range. I have set the meter to 4 watts at dead key when radio was stock. pots were set on 10 watt & 100 watt range to 4 d,k, also. Meter could be generous, ? |
Patzerozero
Advanced Member
Username: Patzerozero
Post Number: 631
Registered: 7-2004
| | Posted on Monday, March 28, 2005 - 4:17 pm: |
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even 20% of 'generosity', i think it should be well under 200 watts.
anyway, try the amp on 'low' & meter on 100 watt scale to see if it shows 70 watts there. then switch to 1000 watt scale & see what it says.
are you seeing backwards swing on the meter on the amp only, or the wattmeter too? you should back down the radio even more til the swing shows 'forward' on both the amp's meter & PDC. if it shows forward on PDC & reverse on amp, then either amp meter is not working correctly or it is exceptionally 'dirty' & the reason you're seeing such high output is it's all in harmonics & going everywhere but the channel you are tuned to.(that's a combination of high swr's and/or overdriven and/or just plain dirty, poorly filtered amp.) |
Musket
New member
Username: Musket
Post Number: 7
Registered: 12-2004
| | Posted on Monday, March 28, 2005 - 8:15 pm: |
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I checked amp on low pwr. watt meter on 100 scale, and watt meter reads about 40 at 3 1/4 dead key . swing to about 100 , swr about 1.3 to 1.4 on meter & radio. i have pdc-30 in line before amp,. coax is 213U 50' Copper made jumper. Amp & pdc swing back wards on high power setting. I have alot in line after radio pdc-27 recieve amp, pdc-3o matcher , amp , then meter.. I do get great reports with the set up but on high pwr with amp it does sound splattered as far as modulation . but it works the best lower powers . does get in to the scanner running more power. had a filter on it but swr went nuts sent it back.
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Patzerozero
Advanced Member
Username: Patzerozero
Post Number: 636
Registered: 7-2004
| | Posted on Monday, March 28, 2005 - 8:44 pm: |
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'I checked amp on low pwr. watt meter on 100 scale, and watt meter reads about 40 at 3 1/4 dead key'-alright musket, that is starting to sound a little better, still maybe high for on 'lo', but better!
&, yea, lots of things in line can make funny things happen. still sounds like the 3+ watt dead key from the radio may be too much. try it even lower & see if amp starts to sound better on high.
you'd be surprised how much difference 1/10th of a watt change in input can make things sound. |
Musket
New member
Username: Musket
Post Number: 8
Registered: 12-2004
| | Posted on Wednesday, March 30, 2005 - 10:11 pm: |
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Would it be possible to take the 455 pills out and replace with 2879s & raise the fuse to 3o amp ? Would u have a dx-350?? |
Patzerozero
Advanced Member
Username: Patzerozero
Post Number: 639
Registered: 7-2004
| | Posted on Saturday, April 02, 2005 - 8:48 am: |
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unfortunately it's not that easy, musket. matching caps & resistors need to be changed to match input/output/get back to 50 ohm impedance. unless you are well schooled in building amps, it's easier to just go buy the dx350.
for a guaranteed increase of at least 1 S-unit, you'd be better off going with a dx400 or 500... |
Musket
New member
Username: Musket
Post Number: 9
Registered: 12-2004
| | Posted on Saturday, April 02, 2005 - 7:52 pm: |
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I didn't think it was that easy, other wise every body could upgrade real cheap.. I don't think i need more power at the moment , what i here local i can talk to they can here me ok.. I can talk father than i can here, even if i run both preamps on . This is what I get with most people i talk to far as signal increase with the amp on, low pwr. 2-s unit med. pwr. 3-s units. 3/4 pwr 4-s units. high pwr. 4 1/4 s-units over bare foot radio.. must be working ok for now , I have talked to Ireland & England with the amp on and with out it , on ssb. West Indies on am. plus about 2/3rds the states in the last 4 years so i"ll keep it for now.. |
Patzerozero
Advanced Member
Username: Patzerozero
Post Number: 647
Registered: 7-2004
| | Posted on Saturday, April 02, 2005 - 8:59 pm: |
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Mrbigshot
Member
Username: Mrbigshot
Post Number: 51
Registered: 2-2005
| | Posted on Monday, April 04, 2005 - 8:39 am: |
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if your 250 has 2 mrf455's it must be really old, mines newer and it has 2sc2290's like the website says. i got 40 key low 3 watts in, 60 key med and 95 key high |
Patzerozero
Advanced Member
Username: Patzerozero
Post Number: 661
Registered: 7-2004
| | Posted on Monday, April 04, 2005 - 3:02 pm: |
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that's about right, mrbigshot. if you can swing in the 150 watt range with the 60 watt key on med, you're in great shape! 95w key on high probably won't get you anymore swing though. yeah, i was wondering, too, if maybe somebody had swapped 455's in after blowing the original 2290's. NEVER saw anything other then 2290's or 2879's in texas stars, except for some of their last version skeleton's & modulators that used, i forget, 1446's or maybe it was 455's... |
Musket
Junior Member
Username: Musket
Post Number: 10
Registered: 12-2004
| | Posted on Tuesday, April 05, 2005 - 10:01 pm: |
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Amp was built 1983 so the skematic says it has 4 pwr settings Mrbigshots. |
Mrbigshot
Member
Username: Mrbigshot
Post Number: 53
Registered: 2-2005
| | Posted on Wednesday, April 06, 2005 - 8:44 am: |
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ohh ya shes an experenced model |
Xmean_n_nastyx1
New member
Username: Xmean_n_nastyx1
Post Number: 1
Registered: 5-2005
| | Posted on Thursday, May 19, 2005 - 8:33 pm: |
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I don't know the year, but i have a DX-250 with the 2290's; are the resistance and capcitance issues easier to deal with? Or should i get a 350?  thanks n 73's |
Patzerozero
Advanced Member
Username: Patzerozero
Post Number: 788
Registered: 7-2004
| | Posted on Sunday, May 22, 2005 - 9:20 pm: |
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the difference in your signal between 150 watts & 250 watts, the REAL output of a dx 250 & dx 350, will be so MINIMAL, that changing the transistors, or changing amps is NOT worth the effort. to get yourself roughly a 1 S-unit increase in your signal(local or skip), you need to double your output. at the very least, that would be to go to a dx 400. if you're running mobile, chances are your vehicle would handle a dx667 or dx500, which you'd use depends on the radio, but you COULD see a 1-1/2 to 2 S-unit increase in your signal... |
Xmean_n_nastyx1
New member
Username: Xmean_n_nastyx1
Post Number: 3
Registered: 5-2005
| | Posted on Saturday, May 28, 2005 - 9:26 pm: |
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Hey Pat,
What's the MAX input you can key into a ts dx 500? I know that for sound, power and reliability, 1.5-3 watts is optimal, but what is to much? What will blow up the key up tansistor? |
Patzerozero
Advanced Member
Username: Patzerozero
Post Number: 825
Registered: 7-2004
| | Posted on Saturday, May 28, 2005 - 10:42 pm: |
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on texas star's website, they have 2 models, a dx500 & dx500v. the v is just a variable version of the 500, they DO NOT list an HDV any longer-high drive variable. what they have listed says 4 watts dead key, they old hdv version said 10 watts dead key. i posted elsewhere, in theory, each 2879 should handle 10 watts pep input, therefore 40 watts pep input & again, theoretically 10 watts carrier. if you were using a magnum w/topgun, you'd have your 40 watts pep, & carrier could be varied up from 1 watt. whatever radio you use, i'd key with 2 watts & let it swing. the dx 500 should dead key about 150 & swing 450+. if you do it with 2-3 dead key, then you're good. if it takes more then 4 or 5 to get 150 watts, go slow & check for heat. make sure swr's are under 1.5:1 1st.
more then 10 watts carrier or 50 watts pep into a mass produced 4 x 2879 amp...every time you key it & it lives is a bonus. keep it LOW. |
Xmean_n_nastyx1
New member
Username: Xmean_n_nastyx1
Post Number: 4
Registered: 5-2005
| | Posted on Sunday, May 29, 2005 - 7:57 pm: |
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thx Pat... was just curious. I run a Galaxy 77 and a Palomar mod v. Wondered what to set the modulator @. I figured 1-2 on radio, and 4 out of the modulator. So i guess that would fall in your guidelines. Thanks again!! |
