• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Tram D201a

sir. witchback

Pied Piper
Sep 26, 2009
28
1
11
44
WV USA
My brother is wanting to trade me 3 Tram D201a's. I have no idea if they work, or not.. Nor does he. (2) are 40 ch, and one is a 23. I was thinking about cleaning them up to sell. Would it be worth my while?
 

Yeah, they are great radios.
The 23 channel radio would be better with a Siltronix 90 VFO; but I'm sure someone will still want it for what it is and find the VFO themselves.

The 40 ch radio will sell faster, as it is a favorite for those that know their CB's.
SO long as it works and it isn't damaged, you should do all right...
 
The Trams have a built in VFO which was usable in transmit mode with a simple mod, no need for an outboard VFO. the 23 channel covered 40+ no problem, and is easily modified for more. Depending upon where/to whom your selling the 23 (D201) channel can be more desirable and have more worth. It also depends where the radio was assembled.

The Tram 201A (40 channel) had a few trouble-spots, Channel Selector is probably the worse. there are a few common ones that plague both. Typical the most valuable Tram in the 201 series is the Hand wired version, which is also easily distinguishable from the others by its available Vox feature.

Depending on condition you could have anything from $75 dollar parts boxes, to 500+ dollar treasures.

Even if they currently work, the potential for costly repairs/parts replacement is very likely, mostly due to age.

Electrolytic capacitors, Under rated,Over-heated resistors, loose/lifted traces on circuit boards, bad tubes. These are among the common problems with a used D201.

Don't let this put you off, the Tram is a desirable and excellent working vintage radio given proper maintainance and care.
 
Just to clarify, the D201 was 23 channel, and all D201A's are 40 channel with the channel selector that went south. They are still popular, and will sell, but condition is the deciding factor.

PR
 
cool beans guys. I have been beating around on the idea of getting them and going through em all the way. If nothing els, They might look nice on my shelf. What is the typical power out put on these, and frequ range?
 
Frequency range and power out would also depend upon mods that have been done to the radio.

Its been a number of years since I had a D201A, from memory transmit on the variable was up around 27.8-9ish, and a few below 1. the D201, I believe is about 27.6 and a few below 1. The 201 I have here has also had the common -1 mod done and with the flip of a switch goes down around 26.3 or so.

As for Power out, a good working 201 with good tubes could be made to easily run about 12 watts carrier, maybe 30-35 PEP. also another common mod which involved jumping some large power resistors to increase voltage. Many mods to the radios over the years, some even put 6146 in for the PA.

I would suggest forgetting about "Strapping" the power resistors, and leave it at stock voltage, leave the 6L6 coast along at the factory original output level which yielded 3-8 watts or so. My reason for suggesting this is the cost and difficulty in obtaining suitable 6L6 tubes. Which are in big demand by the audio guys Good RCA 6L6 tubes will easily bring $50 each, and they won't get any cheaper....
 
Last edited:
I would have to agree with leaving the radios output stock. They are getting older, and the parts were marginal when new, and will be strained by modification. Extra heat means extra problems. Besides, they are one of the best sounding radios to begin with, so why not just enjoy a Tram as it was meant to be.(y)
 
Plan to change out some of the resistors on the printed circuit board models. They drift high and make the receive deaf.

The world is full of cheap 6L6s. There are certain suffix 6L6s which are sought after by audio pholks. You won't need those types. That radio does indeed make a nice 12 watts and about 50 P.E.P. with one of those wirewounds jumpered. It can make 30 watts carrier if more are hacked across but the modulator does not keep up.

I put a pre-war 6L6 in mine just to be on the air with a 70 year old tube.

Any power mods need to be followed by adjustment of the AM audio compressor to keep negative modulation below 100%. The compressor circuit is very good. Find a good D-104 cartridge for best transmit audio. No preamp is needed. That will actually make the tone worse.

Noise blanker is pretty good.

Widebanding the thing will probably show up the usual CB radio bandwidth fall off problems. I have one on 10 meters and it works well across 300 khz then Po and receive start to roll off.

A rough estimate of the use of these rigs is to look at paint discoloration on the underside of the lid. The tOOb's heat gets to the paint.

Best of luck.
 
Hey HiDef post a source for these "cheap" 6L6 tubes, american made? perhaps your definition of cheap is different then mine.

There is also a noticable difference in the audio quality of the radio with crappy 6L6, and some of those cheap russian/chinese tubes just don't cut it...


I'd definitely not run a 201 that hard.... even at 12 watts the transmitted audio starts suffering without mods

Pretty much any of the US made 6L6 will bring 30+ dollars, and about 15% more if your willing to ship to Japan..
 
Last edited:
Gotta say I love my Tram D-201 VOX radio. As far as an out of the box radio goes, this was the best sounding CB rig ever produced. Plate modulated audio from a 25 watt 6L6GC sure had Browning stumbleing to acheive the same audio and power output. The Tram still sounds good with the smaller of the two wire wound voltage dropping resistors shorted. Will key about 10 watts then with lots of PEP.

Thanks to Svetlana, the problems of locating a quality 6L6GC are over. Check out the SV6L6GC. The tube is about $35 and has been designed to be a winner. Heavy mica insulators, gold grid wires, and heavily coated oxide cathode really gives some stiff competition to the old RCA.
 
Any power mods are almost guaranteed to cause trouble. Circuit board damage is almost guaranteed, and power supply problems are probable. Lots of these great radios died at the hands of uninformed modders. Look at all of the trams being sold on ebay with problems.Remember, these radios are getting pretty old, and were built with parts that were just able to do the job, and not much more. They work great as designed, so why do more that a good tune up?:confused:

PR
 
Any power mods are almost guaranteed to cause trouble. Circuit board damage is almost guaranteed, and power supply problems are probable. Lots of these great radios died at the hands of uninformed modders. Look at all of the trams being sold on ebay with problems.Remember, these radios are getting pretty old, and were built with parts that were just able to do the job, and not much more. They work great as designed, so why do more that a good tune up?:confused:

PR

Packrat makes a valid point however it only applies to the D-201A made in Mexico. Just before Tram went out of business they tried to cut costs. The core on the power transformer used in the last radios made was 33% smaller in size and 33% less powerful. Evidence of this is found by looking at the power output stages of late model radios. The final tube was stepped down to a 6DG6 and a 10 ohm resistor was added at the final tube socket to reduce output.

This is certainly not the case with the older D-201. The radio was a powerhouse with a 6L6 modulating another 6L6 and a power supply with plenty of headroom. These tubes are about four times higher plate dissipation then the 6AQ5 or 6BQ5 used in any other CB output stages. With this in mind I have to disagree with this radio being built without extra headroom.

Most failures in the D-201 are related to the old carbon resistors changing value, filter caps drying out, and tubes gone bad. All of these problems can be greatly reduced by installing a small fan on the back of the rig. I can't count how many Trams I've seen over the years with open resistors in the B+ line feeding the SSB IF RX tubes. I can count how many I've seen with a blown power transformer. It was a single D-201A in decades, made in Mexico.

I suppose it really comes down to what you are doing with the radio as to if you should mod it to do more power. For example if you're driving an amp, 2 or 3 watts either way could make a huge difference in output, while being barefoot this power change means almost nothing. An old Tram with the full sized power transformer can easily make twice the rated carrier and still 100%modulate it without stress.
 
Jumping the wirewound resistor to make the radio do 12 watts makes zero change in the power transformer's load. The transformer delivers power to which is wasted as heat in the resistor or extra DC power input power to the final when jumpered.

If your D201 can't fully and cleanly modulate 12 watts of AM/50 watts P.E.P. (with the resistor jumpered) it's sickly and needs attention.
 
If your D201 can't fully and cleanly modulate 12 watts of AM/50 watts P.E.P. (with the resistor jumpered) it's sickly and needs attention.

let me make this a bit clearer, and this IS from experience, and was noted on BRAND NEW, fresh out of the box 201 radios.

Increasing output power beyond 7-8 watts carrier WILL make a noticable difference in transmitted modulation. Will the Tram 100% modulate A 12 watt carrier, yes it will, will there be a notable difference in transmitted audio between a 5 or 6 watt carrier, and a 12 watt carrier, YES there will be. Will this difference be recognizable by an average CB'er probably not.
 
I think what some people miss here is that these resistors are not just voltage dropping resistors. They are part of the Heising modulation circuit used in the radio. These resistors have an electrolytic cap across them for a reason. The resistors reduce DC power to the tube while the cap allows the AF modulation power to pass through without reduction. The overall effect is reduced carrier and increased modulation.

There is obviously going to be a balance here between the maximum carrier that can be produced while still being able to fully modulate it. As mentioned this limit is around 8 watts carrier. That's why you should only bypass the smaller 1.5 K ohm 10 watt resistor if you need more power and not the 2.7 K 15 watt.

A previous post suggested that this will not place more load on the power supply since we are no longer wasting power as heat in the resistor. This is not exactly correct. You will place about 20% more load on the plate supply because without the resistor there is more current flowing. Less resistance means more current. Voltage divided by resistance will tell you that.

Some may find this hard to believe but I once modified a D-201 for a customer that produced a 35 watt carrier with 140 watts PEP! The final stage was still class C and plate modulated. I replaced the AF and RF tubes with 6146B's and replaced the power transformer with one that made 600 volts DC.

I regulated the screen voltage on both tubes with OA2 voltage regulators, used a zener for cathode bias on the modulator and replaced the modulation transformer. Added an adjustable voltage regulator for the solid state pre driver so that the radio could have variable power too.

One thing I did overlook was the mode switch could not handle the extra B+ voltage across it's contacts and flashed over on the first transmission! I replaced the damaged wafer in the switch and rewired it so a relay would switch between modulated B+ on AM and pure DC on SSB.

This modification is very labor intensive and took over 40 hours of bench time. The only reason I did it was because the customer said "money is no object if you can accomplish what I want! A thousand dollars later and one week in time produced exactly what he wanted 10 years ago. The radio is still working great today with no service time at all.
 

dxChat
Help Users
  • No one is chatting at the moment.
  • dxBot:
    Tucker442 has left the room.
  • @ BJ radionut:
    LIVE 10:00 AM EST :cool:
  • @ Charles Edwards:
    I'm looking for factory settings 1 through 59 for a AT 5555 n2 or AT500 M2 I only wrote down half the values feel like a idiot I need help will be appreciated