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Super star 250 amp
- Thread starter abelacres
- Start date
I used to buy these by the case, at the time they were using MRF-455's.
I had one simular years ago but mine was a Super Star 200 and looked the same but was gold in color and had a yellow faceplate. Im sure yours has the same final transistors which were a pair of SRF-3749 which are 80 watt devices. 80 watts x 2 is plenty of boost to get you heard.
The yellow ones were the early versions coming out of WA state. They did use mostly the re-labeled motorola transistors (SRF series). The later ones were made by a different outfit, called "Vern" in Texas. (no kidding on the Vern name) They for years supplied H&Y, copper, and MANY other places with the "palomar" and "boomer" amplifiers. They used the 455s, then when they dried up and prices went up, they went to 1446s. Not a bad amp after some design changes, but they did have the really funny AB bias circuit that they couldn't get to work properly, so they just tied it to ground to disable it because when tey tried to run it that way, it would oscillate due to improper values of components and no negative feedback.
I call it "funny" because they would still put the parts on the board for a crude AB design, BUT then disable it. Why not just ground the bases of the transistors and save money on the parts? My guess is they didn't know how to change it, or already had thousands of the boards made...don't know.
Anyways, if you remove the ground choke which disables the bias, add negative feedback, change a couple caps, add RF bypassing, and add a fan, it can be a nice little amp.
I call it "funny" because they would still put the parts on the board for a crude AB design, BUT then disable it. Why not just ground the bases of the transistors and save money on the parts? My guess is they didn't know how to change it, or already had thousands of the boards made...don't know.
Anyways, if you remove the ground choke which disables the bias, add negative feedback, change a couple caps, add RF bypassing, and add a fan, it can be a nice little amp.
The Gray (150, 300) amps are way better than Boomer, Palomar, and the cheap copies. Call it vintage and you can get $100 on ebay for it.
I remember at one time H & Y had a 1x4 Boomer, Palomar, and Gray amp that all looked the same except for the sticker on the front. I think they also sold several versions of the amp pictured in this thread.
I had a moified or revamped Boomer 600 it had 1 SD-1446 driving 4 SD-1446 it worked great but also had updates starting with a lower guage power and ground wire I believe it had been upgraded to 8 guage wire. It also had things redone inside. The Palmomars Boomers Galaxy Shooting Star Super Star and White Tornado are all pretty much the same amplifiers.
Now the older Pride and Gray amplifiers were better amplifiers aswell as the older Palomar and Messenger amplifiers. I have a older solid state base amplifier somewhere around here thats a 4 transistor Il believe its a Gray but not sure. Its black with red writing on it that says GB 300 on the face. It worked great when I actually hooked it up but Ide like to know forsure who made it.
Ill dig it out and post a pic and see if maybe someone will recognize it and beable to tell me exactly who made it. It uses 4 not so common final transistors and I see in my older amplifier book that the Gray manufacture did use the same transistors in some of their amplifiers like there 300 mobile model.
Now the older Pride and Gray amplifiers were better amplifiers aswell as the older Palomar and Messenger amplifiers. I have a older solid state base amplifier somewhere around here thats a 4 transistor Il believe its a Gray but not sure. Its black with red writing on it that says GB 300 on the face. It worked great when I actually hooked it up but Ide like to know forsure who made it.
Ill dig it out and post a pic and see if maybe someone will recognize it and beable to tell me exactly who made it. It uses 4 not so common final transistors and I see in my older amplifier book that the Gray manufacture did use the same transistors in some of their amplifiers like there 300 mobile model.
Sounds like the 1x4's Vern used to sell, sold quite a few of them back in the day too.
Looks like the palomar 200 I have with 2 1446's in it. It does have the auto delay for ssb and is clean on ssb, at least mine is or I have been told by several people while dx'ing, I use it with a uniden 980. On am I set the dk to 1.5 watts and on ssb it does about 15 watts. Works well. Not sure about the biasing, mine doesn't have that ab sticker on it, but I do use it for ssb and get compliments on it, I would think that guys that I talk to regularly would tell me if it sounded bad. JMO
I would use a 25 amp or more power supply. You might be able to use less, but more is always better. MegaWatt, a site sponsor here sells the S400-12 which is a 36A power supply for $60 plus shipping. I own one and will say that they work very well and have no hash or noise issues. I use mine on an Icom 746 and many others use them here as well and will vouch for the quality of them as well as the great customer service as well. I have ran a 2 transistor (2 pill), amp with Toshiba 2879's in it and it didn't have an issue with making full power out of the amp which is a magnaforce 350hd. So I would think it would work quite well for that amp. I also have one that looks just like the one pictured. It's a bit scratched up, but it's the same amp. Here is he one I have. Hope this helps. And for the money the MegaWatt power supplies are a great buy. I know a local that owns the S700-12 which is a 50A supply and it works well too. Just look around the site here and you'll see the advertisement for the MegaWatt power supplies. They aren't like the cheap knockoff China clones either. Way better filtering and like I said, I've never had any noise or hash issues or any other issues with mine. Just keep the fan clean and it will last you a long time. And like I said as well, the customer service is great. Even the S350-12 would work with this amp. Just some food for thought and JMHO's about tbe power supplies. I'm sure others will agree they are well worth the money. And here are the pics of my amp that is like the one posted. I don't have all the markings like the one shown, but it's the same amp. Just keep the input drive low and it will not sound bad at all. 8-10 watts pep on AM with a 2w max DK, and 12-15 watts max on SSB, and it will do fine. I have since lowered my power on SSB on my uniden 980 to about 8 watts on SSB and it keeps the radio much cooler and the amp happy as well. Yes you might not see as many watts on the meter, but it's not enough that anyone will notice the difference. Again, JMHO's. Hope this helps. Have a good one.
