Brand New Desktop 600 watt Solid State Amplifier

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Brand New Desktop 600 watt Solid State Amplifier

Post by N4ATS » Fri Oct 12, 2007 11:18 am

I have rebuilt some 450 Yaesu FL-7000 amplifiers and with so many new solid state "complex" amplifiers on the market, I am in the process of designing a brand new simplified desktop 600 watt amplifier similar in style to the FL-7000 and basic features like band tracking, LEDS, Analog Meters and simplified user friendliness. This amplified will have that “Kenwood / Yaesu “ look to it and be low profile (17” X 14”X 5” high). New cooling techniques insure quiet operation.
I am looking for ideas that you as an end user would like to see, unlike competitors who never ask, we are asking up front.
A website linked to my web ( will be up soon with status and pictures as development occurs.
Please email your comments or ideas that YOU would like to see in a new amplifier to grassa at
This is also posted in the QTH feedback forum for comments
73's from:
18.133 Mhz.

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Post by K6HT » Fri Oct 12, 2007 2:52 pm

Hello Bill.

The one thing I would like to see in an amplifier is to be able to hook up using 2 radios at the same time. According to Tom K2ESE Yaesu quadra was originally design this way but was re-design at the last minute. He has a nice mod for the quadra that would allow you to have 2 radios on at the same time. So if you can incorporate this idea and keep the cost to a minimum, then sign me up for one. Thanks for asking.


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Post by K9RII » Mon Oct 15, 2007 8:07 pm

Hi, Bill!

I am very pleased to hear that you will be designing and marketing a new solid state 600 watt amplifier. I know it will be exceptional. As long as it operate properly with my FT-1000D and the K3 that I hope to buy at some point, I am on board with it. With your experience, you will have a top performer.

Good luck with your enterprise and 73, Bill


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New Solid State Amp

Post by K6SBA » Mon Oct 15, 2007 8:20 pm

Hi Bill,

I wish you well in this endeavor.

My suggestions:

Target the price in the $1800-2000 range (Is that possible?).

Consider a switching PS to keep the weight down.

Design as much fault protection as possible.

Is it possible to engineer a SS amp with enough protection so that it can safely be used with an external autotuner?

I really like the FL-7000 I purchased from you, but wouldn't mind something a little lighter and smaller.

73 de K6SBA
David in Santa Barbara CA

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New Solid State Amp

Post by W2DWL » Mon Oct 15, 2007 8:52 pm

Hi, Bill,
All the previous suggestion are very , but I was thinking how about "auto band switching".
But what ever you do I know it will excecptional.
Best of 73

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Post by N4ATS » Mon Oct 15, 2007 9:20 pm

YES , Thanks all and keep them coming!

I few "keys" in the design...

1) Florescent Backlit Meters , ANALOG!
2) Front panel adjustable ALC
3) QRP and low power TX Relay (for the IC-7000 and others with 70 mil max)
4) External Power Supply , DARN good idea. keeps RF Deck easy to cool!
5) Peak Hold!
6) Single frequency controlled cooling fan on over-rated heat sink (12 X 8)
7) 6 - MRF-150's , however use them at 50% instead of 100% , easy 600 watts output.
8) BUILT IN 3dB and 6dB input pad , easy input for those 100 and 200 watt rigs.
9) 60C Warning
10) 80C shutdown
11) NO CPS...
12) Kenwood and Yaesu "looks"
13) 6 meters
14) Simple Band LED's , NO displays and all that crap.

Turn it on , work it , turn it off , thru... Simple

Complexity is NOT always the answer. Simplicity IS...

Keep them coming...
73's from:
18.133 Mhz.

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Post by W7RCS » Mon Oct 15, 2007 9:50 pm

Glad to see someone really asking the field what they would like to have in an Amp!
Personally I would like it to include 6Meters AND a Tuner that will cover 6Meters at the full output. All the new HF rigs now include 6Meters so why not have an Amp that will match the rig's capabilities.

Thanks from a satisfied user of your services on my FL-7000!!!

Richard C. Strick

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Post by w7ry » Mon Oct 15, 2007 10:02 pm

*SO2R Contest capability! With this mode, only one transmitter transmits at one time. But the band switching MUST be fast.

* QSK operation with vacuum relays. No PIN diodes.

* Outboard power supply

* Auto tuners in amplifiers are over rated and not needed

* 600 watts+ RTTY contest rated (This is not has high a duty cycle as you might think).

* High/Low fan speed (Rag chew/Contest modes)

* 120/240 volt operation

* Built in PEAK READING wattmeter with simultaneous SWR/Reflected reading. No cross needle meters.

Sounds like a great project!

Jim W7RY

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Post by N4ATS » Mon Oct 15, 2007 10:39 pm

I agree on the tuner....

Good thinking on the dual speed fan , however I have the heak sink designed already with no need for the jet fan.

The problem is that most manufacturers UNDER-RATE for size. Not here. At work we put a heatsink to a pretty good test and at 12 X 8 inches with 3" fins , ONE 5 inch fan at normal speed kept it cool at 15 minutes key down.

The other thing is direct flow of air. Most just put fans in. Waisted air is more than about 80% because there is no ducting. I am putting ducting in so that 95% of all air goes across the fins and not the inside of the box....

Should have a drawing posted here on the "looks" soon...
73's from:
18.133 Mhz.

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HF amplfier wish list (or wait for Elecraft)

Post by w9gb » Mon Oct 15, 2007 11:46 pm

Bill -

You may be aware that Elecraft is designing 2 HF solid-state amplifiers.
One in the power class that you are describing and another in the legal limit class.

It would be nice to see joint effort by US designers to have a "world beater" --
especially when the US Dollar versus Euro, Canadian Dollar and other currencies are at records lows. It should be possible to be price competitive beyond the US marketplace.
Elecraft did have to pause in their design -- due to the K3 rollout in 2007 -- may be an opportunity?
My K3 is coming soon, so it needs company in a year or so.

Features I hear the most often desired:

1. Automatic band switching (Icom, Kenwood, Yaesu, Elecraft)
2. Automatic antenna tuning option (not cheap)
3. Either analog meters OR the "full LED" approach, such as used by WD7S designs
4. Built in RF/SWR metering
5. Better thermal control -- than other designs
6. Reasonable power supply (weight, etc.)


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Post by N4ATS » Tue Oct 16, 2007 6:41 pm

I am leaning towards a 48 VDC switcher only because it will be a lot less weight. I have used switchers in the past and have been very satified with them.

I am thinking on a design that lets the owner place the power supply on the floor v/s incorporating it into the amp. I like it that way and I assume most do as well.

I am also thinking for easy "is it at 48VDC?" having three LEDS on the front of the remote power supply , Red Yellow and Green. Self explanitory...

I found a new heat sink today. The "fins" actually have a top on them that covers the entire fin area. It will be easy to duct air directly through it for maximum cooling at minimum noise.

The question came up today about using a standard 13.8 VDC componant for RF. This will give the owner a couple options...

1) Use it mobile
2) Use his own power supply , like an Astron RS-70M

73's from:
18.133 Mhz.

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Post by VE3TMT » Wed Oct 17, 2007 12:17 am

Hi Bill,

Great idea! I have never owned an amplifier in my life. I do yearn for a mid power solid state amp in the 400-600W range for a little help in the RTTY contests. 120V operation would be nice, and the simpler the better, to keep costs down. I don't need to buy an amp but if the price was right, I'd be in line.

Looking forward to updates on your web site.

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Brand New Desktop 600 watt Solid State Amplifier

Post by W5GA » Wed Oct 17, 2007 5:22 pm

1. Superb documentation with full schematics should be really high on the list.

2. Use finals that won't be either unaffordium/unobtainium in a couple of years.

3. Must do 160m - 10m.

4. Remote P/S is good.

5. Use standard connectors, nothing offbeat/proprietary. Any necessary connectors should be in the box with the amp.

6. 100% duty cycle, any mode, no time limit. Think of the original Alpha ads. That sold them a lot of amplifiers!

7. QSK ala TenTec regardless of exciter.

8. Lots of protection from those 3 a.m. contest screw ups like wrong or no antenna, etc.

9. Offer it with either SO-239's or N's.

10. Auto band switching regardless of exciter.

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Post by N4ATS » Wed Oct 17, 2007 6:19 pm

YES , thats alreay in my head... Standard connectors!

One thing I am going to do is incorporate QSK.

The duty cycle is already done , we ran 600 watts for 15 straight minutes on a new style heat sink and forced "ram" air thru ducting. Perfect...
73's from:
18.133 Mhz.

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Post by K2DC » Wed Oct 17, 2007 7:10 pm

Just curious as to why this thread is in the Feedback Forum, which is supposed to be for feedback on specific swap and sale transactions. It's getting a lot of positive responses, but it looks to me as though it should be in the Swap Caht Board rather than the Feedback Forum, but I could be wrong.
73 All,
Don, K2DC

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Post by N4ATS » Thu Oct 18, 2007 11:46 am

Because this is the perfect spot for it , it IS feedback and it IS about something new that we need info on and EVERYONE is helping out.

This area IS exposed the most as well.

Hope this helps answers your question.
73's from:
18.133 Mhz.

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Post by KA9FOX » Fri Oct 19, 2007 3:54 am

N4ATS wrote:Because this is the perfect spot for it , it IS feedback and it IS about something new that we need info on and EVERYONE is helping out.

This area IS exposed the most as well.

Hope this helps answers your question.
I'm glad it's working out well, and I applaud your efforts to get feedback from the customers BEFORE it is designed... but the Feedback Forum is not the place for this. The Feedback Forum is only for buyers and sellers to discuss specific transactions with other buyers and sellers.

I have moved this discussion to the "Free for All" section, which is more suitable. I left a link from the Feedback Forum so people can still find this discussion, as a personal favor.

73 - Scott KA9FOX

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Post by N4ATS » Mon Oct 22, 2007 10:52 am

Steve is putting a link on my web for the process of the new amp, stay tuned...
73's from:
18.133 Mhz.

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