Solid State Amps
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When I attended Dayton this year and reading the magazines, I see there is now a great interest in solid state amps. I thought that these amps were...well...not as efficient as tube amps thus not being attractive to hams. I guess we wanted BIG iron for an amp. Ameritron has two amps out for quite some time...the 500 and 600 with the 600 now coming with a switching PS. It seems people who own the 600 watt model like them very much. Even "E" has the contesters contest amp and it is solid state. So, what has changed? Have the SS Amps gotten more efficient? Higher voltages? What effects the efficiency of these amps where now there seems to be a market for the Japanese and the Italians. Now most radios provide 100 watts output using transistors and the tube finals in rigs have long been gone. So, is this just a natural evolution of amplifiers or is some new technological breakthrough happened in high powered solid state amplifiers? Lee - K0WA In our day and age it seems that Common Sense is in short supply. If you don't have any Common Sense - get some Common Sense and use it. If you can't find any Common Sense, ask for help from somebody who has some Common Sense. Is Common Sense devine? _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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>From a purely manufacturing point of view, it's a lot easier to make a solid
state amplifier, particularly with surface mount parts and flow soldering on a production line. Thousands can be made with high accuracy and repeatability and that alone reduces a major cost centre which is the manufacturing labour. Cheaper, more reliable devices and magnetics come close behind but I think design has to be more clever and equipment in the design process is more expensive to ensure stability. However, an rf transistor is the fastest fuse on 3 legs ! It's a lot easier to let the smoke out. David G3UNA ----- Original Message ----- From: "Lee Buller" <[hidden email]> To: "Elecraft Reflector" <[hidden email]> Sent: Friday, June 01, 2007 3:01 PM Subject: [Elecraft] Solid State Amps > > > > When I attended Dayton this year and reading the magazines, I see there is > now a great interest in solid state amps. > > I thought that these amps were...well...not as efficient as tube amps thus > not being attractive to hams. I guess we wanted BIG iron for an amp. > > Ameritron has two amps out for quite some time...the 500 and 600 with the > 600 now coming with a switching PS. It seems people who own the 600 watt > model like them very much. > > Even "E" has the contesters contest amp and it is solid state. So, what > has changed? Have the SS Amps gotten more efficient? Higher voltages? > What effects the efficiency of these amps where now there seems to be a > market for the Japanese and the Italians. > > Now most radios provide 100 watts output using transistors and the tube > finals in rigs have long been gone. So, is this just a natural evolution > of amplifiers or is some new technological breakthrough happened in high > powered solid state amplifiers? > > Lee - K0WA > > > > In our day and age it seems that Common Sense is in short supply. If you > don't have any Common Sense - get some Common Sense and use it. If you > can't find any Common Sense, ask for help from somebody who has some > Common Sense. Is Common Sense devine? > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by k0wa@swbell.net
-----Original Message-----
From: Lee Buller <[hidden email]> >I see there is now a >great interest in solid state amps. >I thought that these amps were...well...not as efficient as tube amps thus not >being attractive to hams. >So, what has >changed? Have the SS Amps gotten more efficient? In the case of truly *linear* amplifiers (not Class E or Class D), I don't think the SS amps have gotten much more efficient than they were years ago. What *has* changed is this: First, the cost of a tube amp keeps increasing because the tubes themselves and the parts around them are low-quantity items. You can still build a tube amp for cheap *if* you don't insist on 100% new parts. Rig manufacturers have to use all-new parts, though. Meanwhile, the cost of SS keeps going down. I also think the dollars-per-watt cost of RF transistors has gone down and the watts-per-device has gone up over the years. Second, under the old rules of way back when, we hams measured power by DC input, so efficiency was a big deal, since at the legal limit, higher efficiency meant more watts to the antenna. But since the rules changed 20-odd years ago to output, DC-to-RF efficiency takes a back seat. The difference between a legal-limit amp that's 66% efficient (2250 watts input gives 1500 watts output) and one that's 50% efficient (3000 watts input gives 1500 watts output) is 750 watts at the DC input. That seems like a lot, but consider that with SS there are no heaters to keep warm 100% of the time and that the 750 watts difference is only needed when actually transmitting. Third, switching power supplies. Fourth, things like no fans, no tuning and easy remote/computer control have become more important to a lot of hams, as well as less expensive in the overall picture. Consider a K3, KPA1500 combo - won't *that* be a sweet setup? Yet in inflation-adjusted dollars, it will probably cost less than an S-line of 40 years ago. Fifth, in the old days it was common for contesters to have separate amps for each band so they didn't have to lose time retuning. With an SS no-tune amp, computer-controlled and integrated into the rig, one amp can be just about as flexible as the old stack of them. IOW, it's evolutionary, not revolutionary. And the evolution has been going on a long time. I still remember, as a relatively-new ham, when a QST arrived that showed a legal-limit all-HF-bands all-solid-state linear amplifier on the cover. Full homebrewing details, too - you could build one from the article. Back then I thought "well, we won't see tubes in ham shacks for much longer, because now even the high-power folks don't need tubes in their rigs." That QST issue was for April 1976... 73 de Jim, N2EY ________________________________________________________________________ AOL now offers free email to everyone. Find out more about what's free from AOL at AOL.com. _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by k0wa@swbell.net
On Jun 1, 2007, at 10:01 AM, Lee Buller wrote: > When I attended Dayton this year and reading the magazines, I see > there is now a great interest in solid state amps. > > I thought that these amps were...well...not as efficient as tube > amps thus not being attractive to hams. I think this is true. It's still cheaper to produce several hundred watts with an old tube design than to do so with solid state devices. Although that may not continue for long, as certain tubes become unobtainium, and solid state devices slowly get cheaper. > Even "E" has the contesters contest amp and it is solid state. So, > what has changed? Have the SS Amps gotten more efficient? Higher > voltages? I think the price point for this type of equipment has shifted upward to the point that solid state amplifiers are practical in the market. > Now most radios provide 100 watts output using transistors and the > tube finals in rigs have long been gone. So, is this just a > natural evolution of amplifiers or is some new technological > breakthrough happened in high powered solid state amplifiers? Looks like just the continuing evolution of electronics. Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email] Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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On 7/12/07, Bill Coleman <[hidden email]> wrote:
> > > Now most radios provide 100 watts output using transistors and the > > tube finals in rigs have long been gone. So, is this just a > > natural evolution of amplifiers or is some new technological > > breakthrough happened in high powered solid state amplifiers? > > Looks like just the continuing evolution of electronics. Some of it is an evolution of higher class of amplifier operation, such as Class-E or F or I guess a hybrid of E and F amplifiers for higher efficiencies, when suitable for non-linear operation (CW, some/all? digital modes). 7-MHz, 1.1-kW Demonstration of the New E/F2,odd Switching Amplifier Class <http://www.its.caltech.edu/%7Emmic/reshpubindex/scott.html> E. Lau, K. Chu, J. Qin, J. Davis, K. Potter, D. B. Rutledge, "High-Efficiency Class-E Power Amplifier ," QST May & June, 1997. <http://www.its.caltech.edu/%7Emmic/reshpubindex/poweramp.htm> -Michael, VE3TIX _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by k0wa@swbell.net
In a message dated 7/12/07 11:06:46 PM Eastern Daylight Time, [hidden email]
writes: > On Jun 1, 2007, at 10:01 AM, Lee Buller wrote: > > > I thought that these amps were...well...not as efficient as tube > > amps thus not being attractive to hams. > > I think this is true. It's still cheaper to produce several hundred > watts with an old tube design than to do so with solid state devices. > Although that may not continue for long, as certain tubes become > unobtainium, and solid state devices slowly get cheaper. That's part of it. Another part is that power level measurement has changed from the old power-input measure to the "new" power output measure, so efficiency doesn't matter as much as it used to. > > > So, > > what has changed? Have the SS Amps gotten more efficient? > > I think the price point for this type of equipment has shifted upward > to the point that solid state amplifiers are practical in the market. > > There's also the general amateur acceptance of no-tuneup transmitters. While > it is possible to build tube rigs with no tuneup controls (the CE 100V, 200V > and 600L did it in the 1950s!), it's arguably easier to do with SS. The big item, I think, is the cost and availability of the different designs. Not just the tubes but all the other parts, many of which would have to be custom made. The total price of a conventional tube amp and power supply, with tuning controls and QSK, really starts to climb when you're getting a lot of parts custom-made. That situation is complicated by the used-equipment market. If you want to run, say, a pair of 3-500Zs, and are willing to do your own tuning, a Drake L4 or Heath SB-220/221 can do the job. Even if you have to put fixup into one and retube it, such amps are pretty price-competitive to a new pair-of-3-500Zs amp. There's also the danger of creating an amp whose tubes become unobtanium. You can get a really good deal on the Heath SB-630 amp, because its conduction-cooled tube is very expensive to replace. Elecraft has built itself on the idea of offering products that are *not* exactly like everything else on the market, but rather go off in new and exciting directions. On FD I spent some time with a KX1 - the thing is simply incredible, but also, there's nothing on the market quite like it. The Elecraft amps show that trend as well. 73 de Jim, N2EY ************************************** Get a sneak peak of the all-new AOL at http://discover.aol.com/memed/aolcom30tour _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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