| Author |
Message |
    
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 335
Registered: 9-2004
| | Posted on Thursday, January 24, 2008 - 10:45 pm: | 
|
I am looking for opinions on the DX250,Looking for owners comments pro or con.Is this a good amp,whats the input power,ssb and am ,how good is the preamp, output,splatter etc. how many amps does it draw the usual?I am thinking of getting one to hook up to my 158EDX now that the new cycle is going to be starting to progress in the next year or so.Will be using it on 12,11 and 10 meters.Let her rip I want as many opinions as possible good bad or indifferent.
Tnx Bob CEF451/VE1CZ
Robert L. Spicer The days of radio are just beginning!
|
Tech808
Moderator
Username: Tech808
Post Number: 15146
Registered: 8-2002
| | Posted on Thursday, January 24, 2008 - 11:36 pm: |
|
Captian_radio,
For complete information direct from the Texas Star website on Texas Star Amplifiers:
CLICK HERE > Texas Star Amplifier Specifications.
The 250EX is the same specifications as the 250DX.
Lon~Tech808
CEF#808/HAM#001/CVC#002
Tech808@copperelectronics.com
|
Mrsandman
Intermediate Member
Username: Mrsandman
Post Number: 119
Registered: 1-2002
| | Posted on Friday, January 25, 2008 - 6:55 am: |
|
mine works the best with 2 1/2 watts dead key on
am on ssb would not swing more than 15 wattts
its a great little 2 pill amp. and does very well
for dx and great for 3 towns away |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 336
Registered: 9-2004
| | Posted on Friday, January 25, 2008 - 9:45 am: |
|
Tech 808 I have looked at all the info on the 250 but as well we all know things often turn out very different when we try them out because all setups are different.I do research something quite throughly before I make a choice.Theory is quite different than actual service situations ,radios antennas,type of vehicle etc,so its reading the personal reviews and experiences and weighing the odds and making a decision.Its like the 158 EDX I bought,read the reviews for about a year and made my choice in favor of the 158,now its time for an amp so I will take my time and wait to hear the reviews from real world setups.Tnx so very much for your review of the 158 as it did help me make my decision a lot easier.
Tnx Bob CEF451/VE1CZ
Robert L. Spicer The days of radio are just beginning!
|
1861
Advanced Member
Username: 1861
Post Number: 705
Registered: 2-2004
| | Posted on Friday, January 25, 2008 - 12:58 pm: |
|
I found about the same as MRSANDMAN to be true with mine . very good small amp |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 4126
Registered: 7-2004
| | Posted on Saturday, January 26, 2008 - 10:40 am: |
|
i'd go dx500v with the ss158, bob. 4 x 2sc2879's will feel the pain less then the 2 x 2sc2290's in the dx250! the 250 will see about 40-50 carrier with 2-3 input from the radio, and 150-175 PEP with between 10-15 PEP input. i've used one on a 20 amp PS with no trouble driven reasonably, a bit extra drive popped the breaker. 14 volts is about the max before they have problems-trust me on that one! i have seen a burned voltage regulator in the alternator allow 22+ volts, guages read high, wipers screamed, TS amp smoked on 2nd or 3rd key. all are relatively speaking AB1 biased, and about as clean a CB transistor amp as you'll find. the best preamp i've ever seen on a cb amp was a 1980's version boomer 250. i'd say most TS preamps do what they were made to do-increase whatever the radio is receiving-noise, carrier, heterodynes, etc all get louder. in a quiet setting, they will make an uncopiable signal very copiable. they are rated for 26-30 mc, i'm not really sure what the end result would be at 24.9-i never tried. 28.4 seems to see just a smidge less then 27.1 on the TS's i've touched lately-no 250's though. at one time or another i have owned just about every TS amp ever made, except for the last 3 new ones-dx399, 1000 & 1600v. i used & over-abused every single one of them! if you show low reflect to the antenna, i have never seen any TS amp not show exactly-to-plus-10% of the transistors' it uses', rated PEP output. if the reflect is a bit high, you'll usually see what seems to be some extra PEP. an example being:i've seen more then a dozen 1600's set up mobile, some showing nearly 2kw. setting things up properly & getting reflect back to 2 or 3% dropped PEP to around 1100 every time. everything sounded better, xmit distance increased greatly locally & on dx became more of a 'force'. i have a dx400 here that pretty much does exactly double what i said about the 250. the 400 uses 4-2290's. i have intimate knowledge  of more then a half dozen dx350's locally, 2 x 2879, and they all do exactly what the transistors are rated at. 1.1:1 swr, <2% reflect and no crazy #'s. one is on a 25+ year old galaxy II & with the preamp on makes me want to kill-the white noise is indescribable! 1 is over 20 years old with no repairs ever, the newest is just over a year.
can you make a dx250 work with a radio capable of 10+ watts carrier & 40+ PEP? certainly. if you are careful AND the radio still sounds good when turned down to match the dx250. i've seen some exports cry foul when not 'doing what they're supposed to do'.
even though texas star is my 2nd choice today, i would NEVER discourage anyone from owning one! |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 340
Registered: 9-2004
| | Posted on Monday, January 28, 2008 - 10:49 am: |
|
Ok tnx for the reviews so far and Pat.yours looks like the most comprehensive review,sound like you have lots of experience with them.As far as 12 meters not too important and I will lower the carrier on AM and cut back the ALC on SSB to try and make the 250 happy.Not looking for a big amp so the 250 will probably work just fine for my needs.I just ordered a W1000 mag mount which I will only be using the mag part with one of the new Z-180,s and see how that works out.
Tnx Bob CEF451/VE1CZ
Robert L. Spicer The days of radio are just beginning!
|
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 346
Registered: 9-2004
| | Posted on Sunday, February 10, 2008 - 2:09 pm: |
|
Pat I now have my TS DX 250,10 watts in getting about 150 out on AM,about 20 in on SSB seeing close to 200 out,amp doesn't seem to get very warm and nice thing is the it must have good output filtering because the SWR stays the same with it on.8 gauge stranded wire with 30 amp fuses in both leads running to the battery and seems to like the W1000 very well.Not looking for a big power house that why I opted for the 250.Now all I have left to do is get the Z-180 and give it a try.
Bob CEF451/VE1CZ
Robert L. Spicer The days of radio are just beginning!
|
Dale
Senior Member
Username: Dale
Post Number: 1265
Registered: 12-2002
| | Posted on Sunday, February 10, 2008 - 3:50 pm: |
|
well looks like pat covered about all of it
keep your carrier down to around 2 watts and
pep [swing]arond 10-15 on ssb.20 might be pushing it.thats how i run mine on my omegaforce
till i get a ts500 and bigger powersupply
dale/a.k.a.hotrod
cef426
cvc#64
|
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 353
Registered: 9-2004
| | Posted on Thursday, February 14, 2008 - 11:56 am: |
|
Well I stayed up quite late last nite reading as much info as possible on the DX250.I seem to hear conflicting info such as input power and output power ratings.Now if the 250 has 2 2290,s each rated at 60 watts pep then why does the Texas Star show 20 watts in 250 watts out??Does not seem possible with 2 TR,s that are rated at 60 watts pep=120 pep.Patzerozero has as it seems a very good working knowledge on these amps where the Carrier should be set at 1/4 of the max output.So 1/4 of the pep would be 30 watts carrier peaking from the upwards.Now that does not seem to be much of an output for an amp with 2 2290,s.Why does Texas Star rate them at 250 watts out.
With 2 watts in I am seeing 60 watts carrier peaking 100,with 4 watts in I am seeing 80 watts carrier peaking 150,now this is on a Yaesu YS 2000 watt meter with the pep function.With about 10 to 15 watts pep ssb I am seeing 150 watts pep which looks like a lot less than the advertised 250 by Texas Star.
The amp has great audio and I am not really concerned about getting the rated 250 watts out more curious as to how they come up with these large output figures.
There you go Patzerozero,from what I read from your previous postings here on various amps you have have gained a lot of hands on experience over the years and your opinion will be greatly appreciated and respected
Pat you are the amp Guru.
Tnx Bob CEF451/VE1CZ
Robert L. Spicer The days of radio are just beginning!
|
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 356
Registered: 9-2004
| | Posted on Friday, February 15, 2008 - 7:37 pm: |
|
Hey Patzerozero do you have any other info on the 250 you would like to share with me concerning my personal findings on input and output that I am finding.
Bob CEF451/VE1CZ
Robert L. Spicer The days of radio are just beginning!
|
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 4149
Registered: 7-2004
| | Posted on Saturday, February 16, 2008 - 9:10 pm: |
|
ok bob, with what you stated on last sundays' post (feb 10 2:09PM)....i'm good with those #'s! safe & sound, that amp will last forever & is probably as 'clean' a CB amp as there is run like that. (i push plastic molys into the heat sink fins & add a fan or 2 to all TS amps...can't hurt!).
as for 'commercially made' CB amps....forget the ratings. they ALL lie . take the ratings for the transistor used & go from there. the 2sc2290 is generally considered an 80 watt device, hence the 40 carrier/160 PEP suggestion as you see, you CAN get a bit more out of them by putting a bit more in. at some point though, things begin to dirty up, so you need to know when to stop, based on how much you want to annoy people with bleedover & other trash. 20 watts in gets more of something out, but 15 in may be an all around better # for cleanliness & lifespan. a trick that can help getting max clean output is to set carrier, then adjust for 'swing' in the rms mode. cheezy amps won't always work like this, but some decent-built amps will stop showing an increase in 'swing' in the rms mode at some point. then increase swing in PEP mode, then watch-you may be able to see another 25-50% PEP if you continue cranking input. that additional PEP is the 'garbage'. as i said before though, even 2 transistors rated for 160 watts MAY get you more before things go to heck.
TS suggests their dx250 can actually do 250. davemade, xforce, etc usually rate their 2x2290 amps at 270-300 PEP, and they see those #'s. (compare ratings of TS & dave 4 & 5 transistor models vs actual 2sc2879 ratings! i spoke to svetlana in CA a couple years back regarding the el509 tube & RM italy's suggestion that the klv1000 will do 1400 watts with 4/5 of them. i can STILL hear the guy laughing. yes he said it can be made to see that kind of power. 600-700 is where 4/5 of those tubes should be. anything more is @#$%^&*! i know of several here, output claims range from 600-1400 with varying TVI issues....) the TS can be made to show 250-if it survives, and, 50+ will be trash. the subtle design differences, and bigger transformers in the 'custom' amps will allow them to show more out as well. yes, they can be extremely dirty based upon their 'near' class 'C' operation. take 2 'stock' radios next to each other that run 'neck & neck'. put a TS dx250 on 1 & a davemade 2x2290 on the other. the dave will beat the TS handily. of course the dave will probably beat ALL other local radios 10 channels each way! i've been called a name or 2 in my day for running my davemade-BUT, i'm NOT doing it in my house, i'm doing it mobile, for DX, at a beach away from 'locals' or if i'm driving, it's on the highway & as i travel away, my 'bleedover' will go away. does it make a mess of the airwaves wherever the signal is going? maybe, but, in S9-X db over S9 noise, who's gonna notice anyway? would i run THAT on the amateur bands? NO WAY. another trick is to put a quality low pass filter on any amp. see where the watt meter stops showing additional output in the PEP mode, that'll give you a clue as to how much added nasty stuff comes out. the nasty CAN have some 'talk-power' in it, but it just depends on how much of a 'good citizen' you want to be whether you use all the 'talk power' or just the 'clean' part of it.
so that is 'how they come up with these large output figures'. those figures ARE possible, just not neccessarily efficient. crummy watt meters help too.
thank you for the kind words, bob. my 'guru-ness' comes from my pre-marriage/pre-kids life when i lived at home with mom & dad & ALL my income was 'disposable'. i had no fear of blowing things up. actually, i still don't. back in the late 70's, a 'big mobile' had a 1 tube amplifier in it & did almost 100 watts. a REAL BIG mobile ran an ft101e that probably got another 25 watts out. we took an early 2 transistor AC powered amp, removed the PS & put it in my truck. in 1979 i had done that 2 an 8x2879 homemade amp. one of a few 'known' kw+ mobiles at the time, possibly the only one on LI NY at the time. today, an honest 1kw in the mobile doesn't get a 2nd look. design & the technical stuff may not exactly be my strong point-i am more concerned with performance of amps, knowing what to expect, what you'll get & how & why to change those things. i build for max efficiency, least loss/best match possible & have proven my point many times over when my driver amp has won an impromptu 'key down' vs a bigger amp. and i'm on magnets  . as for w1000(don't care for them, 2k or 5k center loaded TRUCKER version as a last resort-even if used on a magnet, but never a base loaded magnet type wilson!). least coax to use in a mobile with under 500 watts is HIGH QUALITY rg8x/lmr240-type only. never rg58/what comes on a mag mount. using 58 on any hard mount is sacrilege! for even a small mag mount, use one that allows you to change coax to something better. cut open the coax on a wilson factory mag mount....50% shield on a good day??? that too can exaggerate output..... |
Sitm
Intermediate Member
Username: Sitm
Post Number: 237
Registered: 1-2004
| | Posted on Monday, March 09, 2009 - 12:14 pm: |
|
Great information, this is the type of stuff I am looking to read. |
Kf4gyp
Junior Member
Username: Kf4gyp
Post Number: 13
Registered: 11-2009
| | Posted on Monday, February 01, 2010 - 8:17 pm: |
|
Hi Sitm
I find this ironic I am rebuilding my killer bee after killing it 25 years ago. Hey I was young and dumb. I would dk 6 watts in and swing 45 into it with a dx99v.It worked for about 2years putting up with my non sense then it went bang! So tough it is but bullet proof it aint. So i am now replacing both 2290 transistors vari pot and a few other parts. to make it good as new so i can run my uniden pc 76xl with it as a base. I will tell you they do die hard when they let go!! I used to get 175 dk w/6 in and swing to 275 w/45 in. This little amp as long as you are resonably gentle with it it will last long enough to pass it on to youre kids. It is a bit of a current hog though but i dont remember just now how much rite now maybe 25 amps or so.
73 Ray/Hawk-Eye
DE KF4GYP
|
|
