Looking for Amplifier for working with my Flex 6300: suggestions are welcome!

YV5WZ

Royal Star 1300   ;-)

Jim Gilliam

Many hams are social pariahs but it looks like this one has his act together! Wonder if a hair transplant and new chopper would help me?

David Altekruse

Amplifier: Transistor vs. Tube Question

Since I'm shopping for an amplifier and am looking at the ones mentioned here, I've been following this thread with great interest.  My major concern is the transistor vs. tube question that YV5WZ raised at the top.  I've had tube amplifiers in the past (including one I built from scratch in high school back in the early 1960's) and never damaged a tube.  

On the other hand, I've blown the output transistors in my 6300 twice.  (Fortunately it was under warranty both times.)  I don't know how much these transistors cost but FlexRadio support said they were very expensive.  (No one at FlexRadio seems to know what caused them to ****. FlexRadio finally said that their ATU was not able to deal with my antenna's reactance and suggested I buy an external ATU.  I bought the Palstar HF-Auto antenna tuner and haven't had any problems since.)  Furthermore, I can replace tubes myself but probably not the transistors.

As I see it an RF transistor amp has these advantages:  1) No warm up required, 2) usually have protective circuits, auto tuning, and auto band switching, 3) lower power consumption and generate less heat.

Tube RF amplifiers have the advantages of:  1) User replaceable tubes (Adcom's warning notwithstanding), 2) tubes can be purchased from several vendors, 3) cost per watt is lower, and 4) high power tube RF amplifier design is well tested with many decades of use.

As much as I'd like the instant-on and CAT features of the Adcom 600S, my fear of blowing output transistors and paying high repair costs have me leaning toward the similarly priced but higher power Adcom 1000.  Is my reasoning flawed?  Is there any data on high-power RF transistor vs. tube reliability and lifespan?

Burt Fisher

I have a Kenwood TL-922, instant on, and a IC2KL, my concern is duty cycle.

Ross - K9COX

A friend and I have been using a ALS-600 with MRF150's for many years without any problems. On the other hand I ended up selling a AL-82 (3-500's) that was hardly used at all because the finals had to be replaced twice. Never heard of a 6300 having final problems so obviously everyone's experience varies.

Mike W8MM

How about a used Drake L-4B?

Instant-on
low-speed (quiet) blower
1500 PEP out (or more)
Cheap

David Altekruse

Flexradio support told me that 6xxx output transistor problems were rare.   I guess I just had very bad luck .... twice .... in one month.

Is there any reason to believe that today's final amplifier tubes are less reliable or don't last as long as tubes made several decades ago?  (I'm trying to avoid manufacturing location references.)  

Ross - K9COX

In a word, yes.

David Altekruse

Drake L-4B:  No 160, 17, 12, or 6 meter bands.  I'd only miss 17M, though.

John n0snx

The real bottom line is how much $$$$ do you want to spend.... I have ran tube amps from heathkit, dentron, Ameritron to Alpha...and in all the years I have never blown a tube....  I would not have an amp that didn't at least cover all the HF ham bands..( no offence to the boat anchors mentioned here).  There are lots of good amps out there to chose from.... rather than ask whats best and get 20 different answers...(from old boat anchors to brand new). chose three or four venders and do a good research of each one and narrow it down to 1...  IMHO that's the best thing to do....At least that is what I would do...

Bill N5TU

This is good advice.  :-)
73, Bill, N5TU

Steve Gw0gei

I have used an acom 1000 for five years on 6m and Hf contesting -lovely amp and well protected. Alpha 91b worked well too and its replacement (due to age worries) an OM power hf only amp works very well with my flex 6300. Having run a solid state 4/6m Gemini pa for last year with pro 3 and my flex 6300 on 4m and 6m I am sold on the idea of having a solid state main pa to cover 1.8mhz up to 4m . The SPE expert 1.3 kW which will do 4m as well as 6m and Hf is top of my list for a second amp as it also has a built in atu to protect the output. I use resonant antennas on all bands so do not have a atu in my flex 6300. The new offering from acom looks good and the even newer 4o3a solid state pa sounds like it might be a better option than the expert, assuming it integrates well with the forthcoming so2r box. If you opt for a solid state amp it's essential that it has the input protection to cut out and prevent damage - I have lost count of the times my flex and 4m Tvtr put more than 4w out into the 4m pa and tripped it and one occasion when antenna fault caused the swr protection to kick in. The expert 1.3 pa will serve my need for a 6 and 4m pa and also give me a band jumping instant on Hf amp as a multiplyer radio pa in a future so2r contesting set up. - unless the new 4o3a offering turns out to be better for the flex :-) 73 Steve gw0gei

Norm - W7CK

The KPA500 has a VERY LOUD fan.  If you key up for any length of time on AM or any digital mode, the fan will kick into high and you can literally hear it all over the house!  It is obnoxious........  I'll be replacing mine sometime this year. 

Norm - W7CK

Anyone know what the duty cycle of the TL-922 is?

Jim Best

I used my TL-922 with my Flex 5000 and I'm using a Dentron MLA-2500 with my 6300.  Works dandy. Jim WU7G

Burt Fisher

Thanks for the update I hate fans.

Burt Fisher

I never felt it get warm

YV5WZ

Thanks Steve for share your experience with us.....I appreciate it....Thank you! 

James Kennedy-WU5E

I used a ALS-600S with my Flex 6500 the only I can't use to is the ARI-500 the amp works like a champ.

Jim

WU5E

Jim Gilliam

The Flex really shows non-linearity in a linear amplifier. The most notable of improper use is when the base of the signal spreads out on voice peaks. I see this problem on about half of all the signals on the various bands.

YV5WZ

I 'd like to thanks to all who shares experience to answer my question. My Ameritron 811 it's at tech department for being fix.  I'll let you know what happened after repairing (Jim Gilliam), I guess Jim its right about high input cause 100W flex default  . About my decision, I already ordered an Elecraft Amplifier KPA500 & KAT500 Antenna Tuner (thanks to Joe, KQ1Q). I really like Acom A1000, but I'd rather stay away from tubes for awhile and elecraft solid state circuit, quality and automatic change band system match with my Flex for now....Thanks to all!  Hope find you on bands!   

Jim Gilliam

I just acquired a new KPA500 and using it with a Palstar Auto. I love the linear. It gives me clean 500 Watts remotely at my cabin in Big Bear. Very very happy with it.

Jim, K6QE

YV5WZ

My Courier Service already received package from Elecraft, and it will be on its way to Venezuela on Tuesday...so I guess I'll have to wait a week while it's clear at local custom  

Jim Gilliam

Maybe that will give you time to ease things over with the XYL.

YV5WZ

Hahahaha   I not much radio since Ameritron went down.....Cheers!!!

Raf

Seen the Expert 1K-FA at Sals place connected to his 6300 and I don't think it gets better than that. It auto tunes with the radio, has auto antenna selection/switching and a host of other features which I love. He is hoping to get the 2K-FA after which I will grab the 1K-FA from him. )

YV5WZ

yes,  I talked to people from Experts at TX...I liked 1K-FA ...but ATU limit is 3:1 SWR....And if SWR is over 3... amplifier go to fault and it can't be "by pass" .. I have a Hustler Vertical 6BTV and I have to fight with 9-10 SWR on 80 mts and its not really flat the curve on 15 mts ....beside I have to wait 3 weeks for amplifier comes from europe to USA...and the 2 more weeks  to Venezuela....plus that means Taxes to to enter USA...and Taxes to enter to Venezuela.....its cost will be around 6500 $ ...so 1K-FA  was not best deal for me.......by other side Elecraft  is proudly made at USA, its a really well positioned enterprise with lot of quality on its products....500watts  free of worries  of changed bands or high SWR.....Cheers!   

chris hartley (G3VjV)

I'm using the 1K-FA with my 6300, seems a pretty good combination, it tunes my 18m/54ft wire antenna on all bands above 40m, I use a home-brew remote manual tuner on the lower bands.
 I live in the UK so the Expert is easy to purchase here.

YV5WZ

Thank you Chris for you recommendation ...!!! Sadly 1K-FA was not my choice although I'm sure its amazing Amplifier....I went for Elecraft KPA500....I could tell It works wonderful 

https://community.flexradio.com/flexradio/topics/atomic-combination-for-daily-flex-6300-use

Hope to see you on bands

George
YV5WZ

YV5WZ

Message to Jim Gilliam:  
Ameritron 811 amp fault was one of the three tubes, technician told me he think was a tube fail, not cause by overdrive it, he suggested to write to Ameritron....however I dont want to waste my time.....Ameritron its already fixed with all 3 brand new Taylor tubes 

Greetings 

George
YV5WZ
Venezuela