Which Audio Mod for DX-60B?

[KC4VWU]

I know there are several mods for the DX-60 in the tech files. Which one has yeilded the best results so far? I'm going to run it with the GSB-101 leenyar as soon as I can find suitable plate iron for it. Explaination about that will follow after I tuck my bottom lip back in.

Phil

[KX5JT]

I get excellent unsolicited audio reports from my DX-60 with the WC3K mods.  It sure helps to have the adjustable carrier level that is part of the mod when driving an amp.  The overmodulation indicator is right on the money and flashes red then the scope shows the envelop "flat lining" at the negative audio peaks.  You wont be sorry going with the WC3K mods. 

[KC4VWU]

That looks like a pretty simple mod. I probably have everything on hand except for the 50 ohm pot, so I may be able to start gathing everything up this evening.

Next, I need to locate a good plate trans. for the Gonset. Roughly 1KV CT is what I'm shooting for. I know that I could run more B+, but I really don't like to bludgeon the 811A's too hard: to me, the little extra output is not worth killing the life of the toobs. If I can't find somting usd, I may have to look to Mighty Fine Junk for a new one.

Phil

[K4TLJ]

That is a 50K pot... error in schematic.

Here is a schematic of my DX-60 audio mods for your consideration. Not quite as extensive but I received good reports...

http://home.comcast.net/~suptjud/HomemadeHiFi.htm#Heathkit%20DX-60%20Audio%20Mods

[KX5JT]

Heck, 811A's are still under 20 bucks apiece.  They are rated ICAS @ 1500volts for AB2 linear service or CCAS @ 1250 volts. 

http://kx5jt.net/AM/811arca.pdf

Make 'em sing!

[KC4VWU]

It should work out to around 1400v rectified and filtered with 1KV secondary. FW centertap into capacitor input filter; lose the choke and the 866's. That amp is a backbreaker in stock form, so I'm going to clean it up a bit. If need be, I can put it back to original; I had set it up for transcieve a few years back. I found that I had a transformer from a FL-2100B and installed it. Had everything warming up and neglected to take serious notice of the little "tick" sound in the rx.every once and awhile. Dip, load, rest; dip, load, rest. Lookin' good! Dip, load, zaaaaapppp! Frown! It didn't get a fuse or breaker, but it now has that nice arcing sound in the windings; kinda like an arc welder, only not nearly as loud. The iron was a freebie anyhow; guess now I know why. I wish it would have worked out, even though it was probably a little shy on the current capability; I was planning on limiting the carrier to around 100w anyways. 

Phil

[WU2D]

Phil,

Sounds like a fun DX-60 project.

I have an ancient GSB-201 with old 811As inside that I have abused in every way possible hooking it up to unmatched antennas, simple MOPA transmitters, military rigs like the GRC-9 and TCS and WS-19, the Marauder and SR-150 and I can not seem to break it. That solid state power supply is serious for a table top. Table top? - I can hardly move it.

The GSB is simple with 4 811's and an untuned input. One item that it does like is a tuning network on the input. This can be a simple single ended machit with a tapped tuned circuit and an input link or a Pi network. This will help out in many ways including filtering, drive and even linearity. Hooking it to a 15 Watt output 6L6 final transmitter for instance, the output goes from 75 Watts to 200 with the little box!

Mike WU2D

[Steve - WB3HUZ]

Good to hear you on 75 meters this morning. You were strapping here at 30-40 dB over 9!

It should work out to around 1400v rectified and filtered with 1KV secondary. FW centertap into capacitor input filter; lose the choke and the 866's. That amp is a backbreaker in stock form, so I'm going to clean it up a bit. If need be, I can put it back to original; I had set it up for transcieve a few years back. I found that I had a transformer from a FL-2100B and installed it. Had everything warming up and neglected to take serious notice of the little "tick" sound in the rx.every once and awhile. Dip, load, rest; dip, load, rest. Lookin' good! Dip, load, zaaaaapppp! Frown! It didn't get a fuse or breaker, but it now has that nice arcing sound in the windings; kinda like an arc welder, only not nearly as loud. The iron was a freebie anyhow; guess now I know why. I wish it would have worked out, even though it was probably a little shy on the current capability; I was planning on limiting the carrier to around 100w anyways. 

Phil