TX-1 or DX-100B Which one if you has a choice

[Jerry-n5ugw]

I've got a decission to make on which one of these to get. They are in stock condition and I will be running a SB-10 for ventage SSB. Which one would you choose and why?

[Jim KF2SY]

The DX100 has 160.

[Jerry-n5ugw]

Yes it does, but it also has 1625's as moders and TX-1 has EL-84's

[W3SLK]

First, the Apache has EL-34's not 84's. 6CA7's on this side of the pond. Now I echo what Jim said about 160. If you aren't going to operate 160 then it becomes a little more narrower. The DX-100 is a very simple rig to work on. The Apache, a little more flashy-er but if you have noted from the one thread on here, it has its little personality traits. So with that, make your decision. Either one is easy to modify for decent audio without hacking and slashing the chassis.

[WA1QHQ]

I'm not sure how easy it would be to splice an SB10 into a DX100, the Apache was set up to readily accept the SB-10. I have also found the VFO in the Apache to be more stable than that of the DX100 but I'm sure there are mods around to fix that problem. I also found that the SB10 wasn't that convenient to use, it required carrier re-nulling with frequency change and the carrier null drifted over time IIRC, it was a long time ago.

[W3SLK]

Mark said:

I'm not sure how easy it would be to splice an SB10 into a DX100, the Apache was set up to readily accept the SB-10.

Most DX-100B's I've seen have already been modified for the SB-10 adapter. It seems to me that there was a kit you could purchase from Heath for the mod.

[Jerry-n5ugw]

I meant 84's just fat fingered it... Lots of coupling going on with the bandswitch in the TX-1.

[W8IXY]

I'd choose the DX100.  If both are stock, the DX100 has less "tinny" sounding audio.  I modified mine to use 807 modulators, more easily available (at least to me).  I replaced the sockets and wired the filaments in series to run from the 12 volt filament bus.

If you intend to do some audio mods, then the choice is narrower.  The DX100 is easier to modify.

The mod to use the DX100 on SSB was to bring the feed from the driver RF stage out to an SO239 on the rear chassis (some later DX100s had the hole already punched out by Heathkit).  Then another SO239 was mounted on the back chassis right behind the 6146's, and all you needed to do was run a lead from the SO239 to the grid bus of the 6146's.

The other part of the mod was to add two 0B2 regulators in series, and change the screen resistors to the 6146's to allow a regulated 210 volts on them, and add a bias adjustment pot to allow biasing the grids of the 6146's to approximately AB1 operation.

To use the DX100 "straight", you'd build up a short cable with PL259's to connect the driver to the PA grids.  To use the SB10, you'd insert it between the driver output and the 6146 Pa inputs.

73
Ted  W8IXY

[Pete, WA2CWA]

I've got a decission to make on which one of these to get. They are in stock condition and I will be running a SB-10 for ventage SSB. Which one would you choose and why?

I would buy the TX-1. The TX-1 is ready-to-go with the SB-10. VFO improvement over the DX-100 and DX-100B (100 and 100B use the VF-1 design) unless you love drift.  TX-1 also has "time sequence" keying for chirpless CW (great for break-in). Switching for AM/SSB/CW right on the front panel. Has a spotting switch for the VFO. SB-10 color and style match the TX-1. TX-1 has great audio on AM if you read and understand how to adjust the two audio controls. You can use the output of the SB-10, when connected to the TX-1, to drive a transverter for 6 or 2 meters. Buy a matching RX-1 receiver (cough), and be the envy of your fellow hams. Note: to achieve consistent and reliable carrier null with the SB-10, replace the carrier null pots with 5 or 10 turn devices.

[KL7OF]

I would get them both and play with them and get rid of the one I didn't like.....or keep them both as they are both cool tx's...........Steve

[WBear2GCR]

correct me if I am wrong, but I thought both tx's have the same can size mod iron, and that the only difference is the matching (ratio)?

       _-_-bear

[w5rkl]

Both transmitters are nice, I favor the Apache.

A simple, easily done, modification to the DX-100's audio is to change out the 510pf interstage coupling caps to .01ufd orange drops. The same change can be done to the Apache.

The DX-100 had a wider final tank impedance if I remember correctly, something like 50 to 500 ohms or so, where the DX-100B final tank impedance was redesigned for 50 to 75 ohms.

A DX-100B will fit nicely in an Apache, Mohawk, or Marauder cabinet. I don't believe the DX-100 will fit in these cabinets, I could be wrong.

Both transmitters are heavy, not easily moved around on the desk.


73's
Mike
W5RKL

[Jerry-n5ugw]

I could get both and play but I would have to give up the Rx-1 to do so. One concidration is the cost of the modders in the Tx-1. I don't use 160m very much. I have read that if you know how to adjust the pot properly you can get rid of the scratchy sound. Or just mod the TX-1. It seems the DX-100b mod is quite extensive, being I will be in my travel trailer with limited layout area. How detailed is the TX-1 mod.

[w5rkl]

Hello Jerry,

This link shows the schematic of W3SCC and W3YGC's Apache mod. As you can see, compare to the Apache's original schematic, a rewire of the speech amplifier V7, removal of V8 and the 6AL5 clipper tube, removal of the small black round filter, and removal of the pot behind the CW jack. A few added components to the 12BY7 driver tube and the addition of a .01ufd 3KV disc cap across the modulation transformer's secondary.

http://www.amfone.net/AMPX/71_2.gif

My Apache has this mod and the audio is excellent. I use a non-amplified D-104 microphone.

The other, more simpler mod, replaces both 512pf and the .01ufd inter stage coupling disc caps in the speech amplifier to .01ufd 600VDC orange drop capacitor. The 3 caps are located on the phenolic board mounted to the side of the chassis in the modulator section. The schematic showing each of the caps is:

http://k9sth.com/uploads/audio_schematic_1.JPG

73
Mike
W5RKL

[Jerry-n5ugw]

Thanks for the input, I'll see witch one works best at first then mod the other. Once both are done i'll get opinions on which works best and stash to other just incase..

[Steve - WB3HUZ]

Some other DX-100 mods. FWIW, I've heard more good sounding DX-100s on the air than Apaches.

http://www.amwindow.org/tech/htm/dx100.htm

http://www.amwindow.org/tech/htm/dx100/dx100.htm

[Ed-VA3ES]

About 2001 or so, Tim WA1HLR offered to post some Apache mods.  I have here a tape by Tim, describing  Apache mods, which I can transcribe to print when I find some time.
Or, alternatively, I can send the tape to anyone who requests it  for the postage ($5.00).