Is this amplifier a good choice?

[Red 5]

http://pages.ebay.com/link/?nav=item.view&id=141588969111&alt=web

I read somewhere here about the little Italian amps being crappy, anyone know about this one?
Thanks!

 

[tba02]

The one you listed - TC300 - is a chinese knock-off of an RM Italy KL-300.
http://www.rmitaly.us/index.php?main_page=product_info&products_id=9

The transistors used in the TC300 are questionable and I suspect the design could be as well.

There are differing opinions on the RM amps. I have two and have had good luck. They do not like to be pushed hard so you need to keep the input low.

 

[Red 5]

Thanks, which rms do you have?

 

[Tallman]

RM Italy has made improvements and some of them are being FCC certified. The Chinese knock offs are just different enough to keep the law suits away and the transistors might actually be better than the MS-1051's that RM Italy was using.
I have component tester traces that show brand new transistors that could be considered marginal at best. I would not use them in my amplifiers nor would I sell them to any one else.

 

[RatsoW8]

Those amps will never be FCC certified for sale in the US even though RM is touting them as such. From what I can tell all they did was apply for certification and are using the applcation number to falsy list them as FCC certified. If you look at the technical documentation they supplied when they applied for certification you can see it's just BS by RM to obtain the application number. They know the FCC can't do anything about it since they are in Italy.

The amps have no filtering of any kind and would never pass any certification tests for use in the US. Right out of the box they cover the 11 meter band and that't a big no-no.

The skinny from the guys on eHam who tested a few of them is that if you them at about 60% of their rated output they are usable on 10 meters.

 

[tba02]

The KL-300 (unlike many of the others in the lower end RM line) uses 2 X SD1446 BJT's, though I don't know who makes them.

 

[Tallman]

The KL-300 (unlike many of the others in the lower end RM line) uses 2 X SD1446 BJT's, though I don't know who makes them.

Actually the transistors in the KL-300 are MS-1051. They are beta matched something or another and marked as the1051 transistor. The bad thing about the KL-300 is that it is biased as class "C" amplifier. Yes the design is a splatter box from the get go and there is not any filtering at either end of the amp. Only the HLA series amps are filtered.
I always tell every body to run a low pass filter before and one after the amp. It makes a difference in the harmonic transmissions.

 

[tba02]

Actually the transistors in the KL-300 are MS-1051

I was basing my statement on the RM technical sheets. Cannot say with any authority either way. I prefer the KL-503 myself.

 

[Tallman]

I was basing my statement on the RM technical sheets. Cannot say with any authority either way. I prefer the KL-503 myself.

You are correct about the 1446 transistors. For about the last 3 years all I could get for replacements was the ms1051. Got an email from RM saying they would work fine because that's what they were using.

 

[magnuman]

I have the TC300 and it is worse than the worst RM amp. It is class C sounds terrible on air and does just over 100w and gets very hot. The 300 has no relation to the output at all.
Not worth the little they charge for it.

 

[Tallman]

I have the TC300 and it is worse than the worst RM amp. It is class C sounds terrible on air and does just over 100w and gets very hot. The 300 has no relation to the output at all.
Not worth the little they charge for it.

They are truly throw away amps. The cost of the transistors and the technician bench cost more than a new amp.

 

[Mudfoot]

The RM amps I have used have been great little amps. Treat them kind and they'll provide years of use. I'm currently using an RM Italy HLA-150 that works great.

 

[M0GVZ]

I'm currently using an RM Italy HLA-150 that works great.

Have you put it on a spectrum analyser? That is where you find out just how fine they work which is usually "terrible" once you get over 2/3 of their rated output.

 

[Mudfoot]

I keep the output under 120 watts.

 

[psycho]

KLV/RM and their Chinese knocks are not durable and I will leave it at that.