307 Amps 2X6 Base Amp Issue

A 'scope is your friend. Setups that sound killer on AM will sound like doo-doo on sideband. If the radio is already flattopping and slicing off your voice peaks the amp will never sound right. If someone set the radio's ALC for a desired wattmeter reading, that could explain the radio's problem. The low-drive test with the radio alone will either reveal a bias fault in the radio. Or not. Turning the mike gain down to 1 or 2 Watts peak should sound clean. If it doesn't, that's just one of several likely problems with this setup.

The built-in driver creates a severe upper limit on drive level. Even if the radio sounds as clean as the driven snow it will have to be turned down so the driver transistors don't push the six finals to their "flattopping" limit.

In my experience you may find that the highest power level that sounds acceptable is one third or one half the AM peak power.

Not a hard and fast rule, just a typical trend.

73

Checked out his web site, very cool and looks like he does good work. I think his best bang for the buck would be a biased 4 pill base amp. Not a big fan of amps with a driver stage (1x4, 2x4, 2x6 and so on). With most of today’s radio’s being higher power a driver stage is not needed. Something like an old low powered Cobra 2000 or 148 works great on a 1x4 or 2x6 amplifier.
Anyway you have a pretty sweet amp there. Once you get it dialed in and don’t overdrive it should sound great.

Try that again on AM but this time don't flip up the SSB delay switch the one with the blue light. That is why your seeing 4.77w for a couple seconds in the video when you unkey.
As far as your deadkey power... the radio output might be set a little low for AM. Whats that at?
The main power on is the switch with the cover on it I'm thinking.

Doesn't that peak hold keep the number up when you quit talking?

AK321 said:

The center on the switch is standby. Up is AM. Down is SSB.

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You can verify that when you get a chance at opening it up and looking at that switch. If the green wire is soldered to the bottom connection on the switch then up is SSB.
2 watts deadkey might be OK on AM for a 1 pill driving 4 pills but this amp might need a touch more.

AK321, your statement is a bit confusing.

you stated the drive to the amp in PEP numbers which are peak modulated power, and then noted the deadkey coming out of the amp.

i think you had the deadkey on your radio set at 5 watts, and then tried 2 watts.
what is the deadkey set at on the radio that is giving you a 150 watt deadkey out of the amp?
LC

thanks for the reply.

I think your problem is with the radio, the power supply supplying the radio, or the power supply in the amp.

what power supply are you using for the radio?

has the radio had any mods done?

do you have a way to check the input SWR? (SWR meter in the radio would give you this, or put a meter in between radio and amp. amp on, AM mode, deadkey only).
What is that SWR?

you also stated in a previous post that you were monitoring your output on a galaxy radio.
is this radio in the same room with all your other equipment?

im wondering if you are getting "on-air" reports from others or just going by what you hear in that galaxy radio.
it's so close to your other gear, it's probably distorting the receive audio.

i still have a hard time believing that a two pill 2290 section needs a 5 watt deadkey in order to drive a set of 6 pills to a 150 watt deadkey.

hell my 4 pill will do a 100 watt deadkey with 3 watts put into it.

the amp looks nice, and well built. it is biased for SSB the same way many other amps are.

before you send the amp off, it would be a good idea to try to isolate the problem to the amp.

the way to do that is to strategically substitute other equipment in to the chain and see what changes.

also, the more detail you can provide about your setup, the better help you'll get here.
im talking about starting at the power cord and going all the way through to the antenna, listing everything in line, meters and all, and giving relevant numbers where you can.

this will help the techs here set up some experiments for you to do like the one i proposed early in this post.
LC

loosecannon said:

i still have a hard time believing that a two pill 2290 section needs a 5 watt deadkey in order to drive a set of 6 pills to a 150 watt deadkey.

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It's six 2879C's. The 150 watt transistors.

Friend of mine had a 2x6 Fatboy. Nothing but trouble with the two pill engaged. It had a switch to cut the two pill transistor section off. Ran great on the straight six.