k7dyy new 300 watt class D transmitter

[K7EK]

Greetings and salutations...

I have purchased a 75m version of the K7DYY SR transmitter. I must say that I absolutely
love it! When I get on with that transmitter, I am heard, and make lots of contacts. It
plays exactly as advertised with a conservative 300w of carrier. I am told that it will do
considerably more. I got all six channels programmed in 5 khz increments, starting at 3870.

I also purchased one of Bruce's audio processor boards, which is a must with the 'DYY. I
installed it in the base of my D-104. I have received glowing audio reports and nothing but good so far. It is definitely a winner and I highly recommend it. While running 300w of carrier on a typical long keydown AM contact, the DYY SR cabinet is barely warm to the touch.  I have paired my 75m DYY SR with a Drake R4 receiver. The size of the transmitter is less than 1/2 of the size of the R4. This makes for an excellent station that can fit into a very small space.

I like the 75m model so much that I plan to purchase the 160m model in the near future, when
my financial situation permits.

I look forward to chatting with you on 75m AM with my new powerhouse.

Best regards,

Gary E. Kohtala - K7EK

[WA3VJB]

Gary if there's any way someone you're in QSO with can roll a sound file of how they are receiving you, I would really enjoy hearing the new transmitter.

I also wonder if you've collected any thoughts about the characteristics of the audio processing board you mentioned. 

I am very curious whether the attack/release constants are sort of like the kind on your basic communications transceiver, or whether they allow some adjustments for peak limiting and a variable amount of slower acting amplitude compression.

[w1pe]

I have two of the K7DYY Mic Pre amps one on the D104 and one on a 10DA. Only adjustment I have found is the gain control. There is no documentation on it at all. That is the one thing I as well would like to see.

I sure do wish that my Sr had worked out. When it was on the air it was great but it would not stay stable so I am back to the old Globe King  LOL

Bob W1PE

[ve6pg]

...i shud have mine, next week. i chose 160.
  what is this i've heard about using an isolation transformer?...is there some problem i shud be aware of, before i put it on the air?...tim..sk..

[flintstone mop]

Hello All,
I own the K7DYY JR. which was Class D and capable of operating the entire 80M band without tuning. It's being repaired because of the shortcut of not using a transformer for isolation.........my bad and I think Bruce's bad, but he wants $80 to fix. It will have to sit until next month.

My question to the Forum about the K7DYY transmitters is about audio inpoot. I'm feeding mine with 600 ohms unbalanced audio and my EQ settings have to tweeked waaay out from their "normal" settings for the Kenwood/Titan station. How are your Class D or E transmitters performing using a typical Ham Radio station setup/audio chain??? OR no audio chain and or EQ. I'm wondering if my audio impedance is way off making me have to boost-tweek-EQ so much??? Anyone notice the high end restriction?? Too much sibilance and the transmitter goes to pieces!!!
Thanks
Fred

[flintstone mop]

A comment on the audio processor for the D-104.
There are no adjustments for attack/release and the design seems to be for very aggressive processing. In between words I hear my background room noise popping up in the TX audio. I set the mic aside for bad conditions.
I increased power of my "JR" to 200 watts and the modulation went to pot. I reset the power adjust to the 180 Watts approx. and modulation was beautiful. Maybe a weird thing with the Class D design.
When mine returns from repair, it will be nice to be anywhere on 80M and not have to worry about crapstals or tuning. I had good success with the VFO before I zapped the dam thing soldering wires to the PTT plug on the TX, while it was OFF BUT still plugged into the AC mains.

Fred

[ve6pg]

...maybe i missed it fred, but what vfo were you using,  and how did you wire it in?..tim..sk..

[flintstone mop]

Guys
Check with Bruce about using a VFO. I don't think his new generation of K7DYY Tx's will give you that luxury.
And I think he was modifying the PTT circuit to be self contained and no further dangers of zapping the TX because of the lack of isolation transformer.
Bruce recommended a 500VA transformer for the old JR Class D 180Watt.
For you folks buying the 300Watters you will obviously need a bigger transformer.
"BAD THINGS WILL HAPPEN IF YOU DON'T!!!" Quote directly from Bruce

fred

[ka3zlr]

Howdy,

 Well other than some of these short comings that have little solutions to over come..How does everyone that owns one of these things Like'em...I'd like to know...i'm sure others would too, pleased with service.performance..etc..?...

73.

[Ian VK3KRI]

A comment on the audio processor for the D-104.
There are no adjustments for attack/release and the design seems to be for very aggressive processing. In between words I hear my background room noise popping up in the TX audio. I set the mic aside for bad conditions.
I increased power of my "JR" to 200 watts and the modulation went to pot. I reset the power adjust to the 180 Watts approx. and modulation was beautiful. Maybe a weird thing with the Class D design.
When mine returns from repair, it will be nice to be anywhere on 80M and not have to worry about crapstals or tuning. I had good success with the VFO before I zapped the dam thing soldering wires to the PTT plug on the TX, while it was OFF BUT still plugged into the AC mains.

Fred

k7dyy's ccts use either the SSM 2166/2167.  Both chips have a noise gate facility to drop gain below a certain threshold. I was using a different SSM2166 cct here until I went over to using the PC for processing. Changing comp ratio, noise gate point and limiting point  is just a matter of changing resistor values. Check out the data sheets on the Analog devices web site.

http://www.analog.com/en/prod/0,,765_1075_SSM2166,00.html
http://www.analog.com/en/prod/0,,765_1075_SSM2167,00.html

                                             Ian VK3KRI

[flintstone mop]

I found the problem with the quirky weird EQ settings for my "JR".........Bad mismatch from the station audio which is 600 ohms balanced and the inpoot to the "JR". I have many of those BOGEN WMT-1 matching transformers and when I installed it to feed the "JR", it sang it's little heart out with fantastic audio and the EQ is almost flat with a little rise around 4-5khz for listeners using narrow BW receivers.
Now I'm looking for a 500va isolation transformer

Fred

[Ed Nesselroad]

Those of us in the northwest have been listening to Bruce's beta-tested radios for some time.  They sound great.  I'd direct you to W7JHS' website. 
     [url]http://www.w7jhs.com/[url]
where you'll find fotos of Cormack's vast assortment of rigs.  Scroll down to see the DYY junior and senior.  The Senior can be heard afternoons on 3870.

The Senior sounds as good (or better) as any of the other rigs.  Seemed to take just a little on-air adjusting to get the pre-amp set right, but the Senior is a FB AM rig.  Plan to purchase one myself...
 

[ve6pg]

...got my tx about 10 days ago...just working on getting the audio nice...325 watts carrier on 160. so far, i've received gud reports, on the audio, as well as signal strength received...so far, i'm impressed...tim...sk..

[K7EK]

I have purchased one of K7DYY's SR transmitters for 75m, in addition to
his audio processor for a D-104 microphone. I have paired it up with a
Drake R4A receiver.  I must say that I have been extremely pleased with
the quality and performance of the transmitter. It is simply beyond comparison....
When I call, I get answers most of the time. After setting the audio with my
Heath monitor scope, I've been given nothing but superb audio reports. The nice
thing is that this transmitter puts out a very big carrier in a comparatively small
package, and does not even get warm in the process. A typical yay-emm ragchew
session might often entail continuous key down times of 10-15 minutes. With the
'DYY SR,  it just keeps on going and going, never getting warm. I like the 75m
'DYY SR so much that I will soon purchase the 160m model.  I highly recommend
these transmitters. You cannot go wrong. They are worth every penny.
See you on 3870  .

Best regards,

Gary, K7EK

[W7SOE]

Ordered K7DYY Sr. PCBs today.  ;-)

Rich