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 Post subject: New Drake 4B project
PostPosted: Nov Mon 23, 2020 3:59 am 
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Joined: Oct Sun 11, 2020 7:40 pm
Posts: 64
Location: Guthrie, OK USA
I am trying to assemble Drake 4B twins. The T4XB should arrive Tuesday. R4B is still up in the air (EBay). I have to find or make the connecting cables. Sure wish I knew what type of cable to use. All I know for sure is the connectors are RCA type.

I will have to buy an AC4 power supply too but later. Baby steps, not wealthy.

Your thoughts will be appreciated.

Johnny


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 Post subject: Re: New Drake 4B project
PostPosted: Nov Mon 23, 2020 4:45 am 
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The only critical cable is the injection cable which should be low capacity coax, keep it as short as reasonable. The antenna connecting cable can also be made from the same low capacity coax or any small decent coax. The rest of the cables just need to be decent quality shielded because they are at AF or DC.

The most accurate alignment is accomplished once you have them cabled together so that the actual loading of the units and cable is in place.

Enjoy your "new" 4 line. The Drake 4 twins were the choice of most contesters and DXers because of their excellent performance. And unlike most vintage gear, they will easily operate on the later "WARC" bands with the addition of accessory range crystals. Drake also made the FS-4 synthesizer to provide general coverage, there are now also other external synthesizers designed to work with the 4 line.

Rodger WQ9E


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 Post subject: Re: New Drake 4B project
PostPosted: Nov Mon 23, 2020 5:15 am 
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These are great radios. I like a manufacturer that created radios and accessories so you could collect the whole station with one look--radios, antenna tuner, RF power meter, mic's, dummy loads, the works. These Drakes are fairly easy to service and align. There aren't many parts to change--the filter caps and a few paper caps if you desire.

Norm


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 Post subject: Re: New Drake 4B project
PostPosted: Nov Mon 23, 2020 1:40 pm 
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Posts: 7431
Location: Liberty, Missouri
Hi Johnny, Congratulations on your NEW toy. These are seriously nice radios, even with someone's dumb idea of a side mounted, military PL-068 mic jack.

Image

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 Post subject: Re: New Drake 4B project
PostPosted: Nov Mon 23, 2020 7:00 pm 
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Joined: Oct Sun 11, 2020 7:40 pm
Posts: 64
Location: Guthrie, OK USA
rsingl wrote:
The only critical cable is the injection cable which should be low capacity coax, keep it as short as reasonable. The antenna connecting cable can also be made from the same low capacity coax or any small decent coax. The rest of the cables just need to be decent quality shielded because they are at AF or DC.

The most accurate alignment is accomplished once you have them cabled together so that the actual loading of the units and cable is in place.

Enjoy your "new" 4 line. The Drake 4 twins were the choice of most contesters and DXers because of their excellent performance. And unlike most vintage gear, they will easily operate on the later "WARC" bands with the addition of accessory range crystals. Drake also made the FS-4 synthesizer to provide general coverage, there are now also other external synthesizers designed to work with the 4 line.

Rodger WQ9E


Thanks Roger that is what I needed.

Johnny,
KE5YRV


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 Post subject: Re: New Drake 4B project
PostPosted: Nov Mon 23, 2020 7:08 pm 
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Joined: Oct Sun 11, 2020 7:40 pm
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Location: Guthrie, OK USA
Norm Johnson wrote:
These are great radios. I like a manufacturer that created radios and accessories so you could collect the whole station with one look--radios, antenna tuner, RF power meter, mic's, dummy loads, the works. These Drakes are fairly easy to service and align. There aren't many parts to change--the filter caps and a few paper caps if you desire.

Norm


Thanks Norm.

I have already decided to install replacement filter caps from Hayseed Hamfest. They fit the original holes. I will replace the paper caps too. Probably with those yellow Cornel Dubilier caps.

Really look forward to getting it all refurbished and working well.

Johnny


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 Post subject: Re: New Drake 4B project
PostPosted: Nov Mon 23, 2020 7:10 pm 
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Joined: Oct Sun 11, 2020 7:40 pm
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Location: Guthrie, OK USA
Mikeinkcmo wrote:
Hi Johnny, Congratulations on your NEW toy. These are seriously nice radios, even with someone's dumb idea of a side mounted, military PL-068 mic jack.

Image


Mike, can you recommend a mic? I need something until I can find a Drake mic.

Thanks,

Johnny


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 Post subject: Re: New Drake 4B project
PostPosted: Nov Mon 23, 2020 9:28 pm 
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Location: Dallas,TX
Johnny,

With my Drake's I use a Electrovoice EV-644 and a Shure 444. Both sound great. As far as capacitors, change the electrolytics and don't worry about the others. Drake used high quality capacitors and I've never found a bad one. Congratulations on becoming a Drake owner but I have to warn you they are habit forming. :D

Mike B.
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 Post subject: Re: New Drake 4B project
PostPosted: Nov Mon 23, 2020 11:20 pm 
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Location: Liberty, Missouri
Quote:
...Mike, can you recommend a mic? I need something until I can find a Drake mic....
I'm going to defer to Rodger, or "the other Mike", because I don't use VOX, and, my station mic is an Astatic D-104, which has peaked frequency response Drake seems to specifically dislike.

I don't know why that is, but I can only presume their "flat response" preference has to do with VOX operation, and/or audio response shaping in the transmitter's mic audio circuitry.

I did take a quick look at the schematic, and the grid of the input mic amplifier stage has a 3.3 Meg Ohm resistor to ground, which would imply the use of crystal mics would be OK.

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 Post subject: Re: New Drake 4B project
PostPosted: Nov Tue 24, 2020 12:33 am 
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Joined: Oct Sun 11, 2020 7:40 pm
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Location: Guthrie, OK USA
Mike Bracey wrote:
Johnny,

With my Drake's I use a Electrovoice EV-644 and a Shure 444. Both sound great. As far as capacitors, change the electrolytics and don't worry about the others. Drake used high quality capacitors and I've never found a bad one. Congratulations on becoming a Drake owner but I have to warn you they are habit forming. :D

Mike B.
(the other Mike)


Thanks for the warning about habit forming Drakes.

Johnny


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 Post subject: Re: New Drake 4B project
PostPosted: Nov Tue 24, 2020 12:36 am 
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Joined: Oct Sun 11, 2020 7:40 pm
Posts: 64
Location: Guthrie, OK USA
Mikeinkcmo wrote:
Quote:
...Mike, can you recommend a mic? I need something until I can find a Drake mic....
I'm going to defer to Rodger, or "the other Mike", because I don't use VOX, and, my station mic is an Astatic D-104, which has peaked frequency response Drake seems to specifically dislike.

I don't know why that is, but I can only presume their "flat response" preference has to do with VOX operation, and/or audio response shaping in the transmitter's mic audio circuitry.

I did take a quick look at the schematic, and the grid of the input mic amplifier stage has a 3.3 Meg Ohm resistor to ground, which would imply the use of crystal mics would be OK.


Thanks again.

I just received an original speaker for my HQ 160. Sounds grea!

Johnny

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 Post subject: Re: New Drake 4B project
PostPosted: Nov Tue 24, 2020 5:49 am 
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Joined: May Thu 17, 2018 12:16 am
Posts: 96
Location: Edmonds, WA USA
Are there paper caps in the Drake 4 Line? I would expect disc ceramics but the manual doesn't have a parts list. I am thinking of looking for a 4B Line so would like to know.

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 Post subject: Re: New Drake 4B project
PostPosted: Nov Tue 24, 2020 6:06 am 
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Location: Costa Mesa, California
There are a few paper caps underneath the chassis. In the photo of a this T4X they have been replaced with "orange drops." Also a photo of the R4B underneath. I see maybe one or two there.

Norm


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Bottom of R4B.jpg
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 Post subject: Re: New Drake 4B project
PostPosted: Nov Tue 24, 2020 2:28 pm 
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Joined: Oct Sun 11, 2020 7:40 pm
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Location: Guthrie, OK USA
Norm Johnson wrote:
There are a few paper caps underneath the chassis. In the photo of a this T4X they have been replaced with "orange drops." Also a photo of the R4B underneath. I see maybe one or two there.

Norm


Thanks for the pix Norm. I too like orange drops. Good idea.

The next two or three generations in my family can enjoy it too.

Johnny
KE5YRV


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 Post subject: Re: New Drake 4B project
PostPosted: Nov Tue 24, 2020 3:55 pm 
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The C line only needs electrolytics, if anything. I bought the receiver that already had Hayseed cap installed. My transmitter has the original can in it, but I rebuilt the AC 4 with a homemade PC board and new caps mounted on it. And installed a time delay relay I had in an octal socket where a can was removed. Vastly cheaper than buying the custom can caps. I bought the custom dust covers for mine as they are not hardly used on a daily basis. They are secondary to a modern radio. Oh, there was the cost of a new set of finals and several other tubes were weak. I would buy a new set of finals if you intend to use it much as spares. They don't make them anymore and it is hard to tell if supply or demand is greater. Shop around for those, you can save at least 50% off ebay prices for good new matched brand NOS finals. I also tapped 12 filament and rectified and filtered to run a 12V computer, cheap low current fan bolted to the back of the cage to keep some air movment thru the finals. I used the accessory RCA jack hole on the back of the TX for that. The filter is not big enough to maintain full voltage so the fan is lower RPM and is very quiet.

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 Post subject: Re: New Drake 4B project
PostPosted: Nov Tue 24, 2020 4:07 pm 
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Joined: Oct Sun 11, 2020 7:40 pm
Posts: 64
Location: Guthrie, OK USA
wazz wrote:
The C line only needs electrolytics, if anything. I bought the receiver that already had Hayseed cap installed. My transmitter has the original can in it, but I rebuilt the AC 4 with a homemade PC board and new caps mounted on it. And installed a time delay relay I had in an octal socket where a can was removed. Vastly cheaper than buying the custom can caps. I bought the custom dust covers for mine as they are not hardly used on a daily basis. They are secondary to a modern radio. Oh, there was the cost of a new set of finals and several other tubes were weak. I would buy a new set of finals if you intend to use it much as spares. They don't make them anymore and it is hard to tell if supply or demand is greater. Shop around for those, you can save at least 50% off ebay prices for good new matched brand NOS finals. I also tapped 12 filament and rectified and filtered to run a 12V computer, cheap low current fan bolted to the back of the cage to keep some air movment thru the finals. I used the accessory RCA jack hole on the back of the TX for that. The filter is not big enough to maintain full voltage so the fan is lower RPM and is very quiet.


Thanks for the tips. I'll keep an eye open for finals.

I'll be testing all of the tubes soon.

Johnny
KE5YRV


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 Post subject: Re: New Drake 4B project
PostPosted: Nov Tue 24, 2020 4:12 pm 
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With the 4 line (separates or transceiver), always make sure the bias supply filter caps in the mating AC-3 or AC-4 have been replaced. A failure of the bias supply will cook the transmitter finals even in standby mode because they still have plate and screen potential applied.

I use Astatic D-104 microphones with my T-4 series gear. It was a popular choice for the 4 line separates when they were in production because many contest/dx stations used 4 line twins and the audio response of the D-104 was a favorite for cutting through pileups.

6GJ5 finals will also work in the 4 line twins instead of the stock 6JB6 tubes and are often less expensive, a couple sets of mine are using them. Sylvania was the preferred brand by Drake but I have also had good luck with RCA. Avoid the "Servicemaster International" tubes for any position, their parentage is random and they are often junk.

A small fan to cool the finals will add to their life. A simple "muffin" fan with one sided foam tape attached to the bottom and placed over the final cage will suffice.

The 4 line in all incarnations are still excellent rigs and I love my slightly modified C line for CW.

Rodger WQ9E


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Drake line.JPG
Drake line.JPG [ 807.51 KiB | Viewed 556 times ]
drake tc.JPG
drake tc.JPG [ 414.6 KiB | Viewed 556 times ]
Drake VHF.JPG
Drake VHF.JPG [ 238.4 KiB | Viewed 556 times ]
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 Post subject: Re: New Drake 4B project
PostPosted: Nov Tue 24, 2020 4:39 pm 
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Joined: Oct Sun 11, 2020 7:40 pm
Posts: 64
Location: Guthrie, OK USA
rsingl wrote:
With the 4 line (separates or transceiver), always make sure the bias supply filter caps in the mating AC-3 or AC-4 have been replaced. A failure of the bias supply will cook the transmitter finals even in standby mode because they still have plate and screen potential applied.

I use Astatic D-104 microphones with my T-4 series gear. It was a popular choice for the 4 line separates when they were in production because many contest/dx stations used 4 line twins and the audio response of the D-104 was a favorite for cutting through pileups.

6GJ5 finals will also work in the 4 line twins instead of the stock 6JB6 tubes and are often less expensive, a couple sets of mine are using them. Sylvania was the preferred brand by Drake but I have also had good luck with RCA. Avoid the "Servicemaster International" tubes for any position, their parentage is random and they are often junk.

A small fan to cool the finals will add to their life. A simple "muffin" fan with one sided foam tape attached to the bottom and placed over the final cage will suffice.

The 4 line in all incarnations are still excellent rigs and I love my slightly modified C line for CW.

Rodger WQ9E


Thanks again Roger,

I will look for those tubes. Maybe I will stock a couple for future use too.

Johnny
KE5YRV


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 Post subject: Re: New Drake 4B project
PostPosted: Nov Tue 24, 2020 4:44 pm 
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Joined: Oct Sun 11, 2020 7:40 pm
Posts: 64
Location: Guthrie, OK USA
rsingl wrote:
With the 4 line (separates or transceiver), always make sure the bias supply filter caps in the mating AC-3 or AC-4 have been replaced. A failure of the bias supply will cook the transmitter finals even in standby mode because they still have plate and screen potential applied.

I use Astatic D-104 microphones with my T-4 series gear. It was a popular choice for the 4 line separates when they were in production because many contest/dx stations used 4 line twins and the audio response of the D-104 was a favorite for cutting through pileups.

6GJ5 finals will also work in the 4 line twins instead of the stock 6JB6 tubes and are often less expensive, a couple sets of mine are using them. Sylvania was the preferred brand by Drake but I have also had good luck with RCA. Avoid the "Servicemaster International" tubes for any position, their parentage is random and they are often junk.

A small fan to cool the finals will add to their life. A simple "muffin" fan with one sided foam tape attached to the bottom and placed over the final cage will suffice.

The 4 line in all incarnations are still excellent rigs and I love my slightly modified C line for CW.

Rodger WQ9E


I have been looking at EBay for D104 mics. How do you tell a highZ from a lowZ? Ebay listers don't identify them usually.

Johnny


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 Post subject: Re: New Drake 4B project
PostPosted: Nov Tue 24, 2020 5:16 pm 
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Johnny,

I believe all of the original D-104 elements are either ceramic or crystal and they are designed to work into a high impedance.

HOWEVER-a lot of the original elements died so when buying from Ebay you may get one with a dead original element or one where the element died and was replaced with something else so it is a bit of a gamble. In my experience, original ceramic elements held up well but the crystal elements are often dead or severely degraded.

It is possible to retrofit a condenser or dynamic element to the D-104, in the past kits were available from various sellers to do so but I don't know if that is still the case. A lot of later D-104 microphones have a preamp built into the base because that is what the large CB market wanted. In many cases, the ceramic element is still fine and it is the preamp that has died and you can just bypass it. You don't need the preamp for your T-4XB anyway so if the D-104 you get has one I would bypass it to avoid future issues.

The Drake T-4 series presents a very high microphone input impedance and a wide variety of microphones will work well and easily with it. In general, even a microphone designed for lower impedance will work into a high impedance input but with a different audio response; the reverse isn't true and a high impedance microphone generally won't provide sufficient output when looking into a very low impedance load. A few rigs (some Icom sets come to mind) used a condenser microphone that requires voltage from the rig to operate and this type won't work with your T-4XB.

Rodger WQ9E


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