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Author Topic: Why Orange Drops?  (Read 50031 times)
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K6JEK
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RF in the shack


« on: December 29, 2011, 04:01:22 PM »

I have an HRO-60 to go through. What caps to use is the question.

I used to use orange drops because they have a good reputation and seem more period appropriate. But somewhere along the line, I think it was an SX-62, I gave up and switched to yellow poly's because they fit in the crowded wiring. They are smaller and have axial leads. I have to admit, I don't like they way they look.  

Is there any technical argument for orange drops or is it just aesthetics?  And no, I'm not ready to do any capacitor re-stuffing.




* HRO-60detector.jpg (572.48 KB, 2736x3648 - viewed 710 times.)
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W4AMV
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« Reply #1 on: December 29, 2011, 04:34:42 PM »

Good question. I have measured the ESR and RF characterisitcs of both through 30 MHz and saw very little difference. Now the properties of the dielectric could be an issue in some applications and I cannot recall the dielectric type for Orange drop. So dielectric absorption in certain apps is a big deal and the poly I believe are better in those apps, like a PLL. Other opinions are certainly welcome.
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KE6DF
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WWW
« Reply #2 on: December 29, 2011, 04:36:10 PM »

Well there are always silk capacitors with oxygen free copper leads you could use to

"relieve the music's vibration energy"
and to "decrease the peak feeling sound at high compass and rough quality sound at middle compass"

http://www.thlaudio.com/elnaitme.htm

 Smiley  Huh  Roll Eyes  Grin
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K6JEK
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RF in the shack


« Reply #3 on: December 29, 2011, 04:51:00 PM »

Well there are always silk capacitors with oxygen free copper leads you could use to

"relieve the music's vibration energy"
and to "decrease the peak feeling sound at high compass and rough quality sound at middle compass"

http://www.thlaudio.com/elnaitme.htm

 Smiley  Huh  Roll Eyes  Grin
Or I could buy Black Beauties prized by guitar amp builders.
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WA1GFZ
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« Reply #4 on: December 29, 2011, 06:01:58 PM »

Orange drop caps are high quality parts but they are not RF caps. I would not use them for low Z bypass above about 1MHz without a disc ceramic in parallel. High Z circuits they are no worse than a wax cap but far higher quality. They should out live you if used properly.
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KM1H
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« Reply #5 on: December 29, 2011, 08:22:31 PM »

Tests myself and others have run on those to settle arguments show that the values used in that radio are series resonant in the mid HF range and are far from effective in the front end stages. Paper caps were even worse.

National started with all paper, then a mix of paper and mylar, then mylar and disc ceramic. This was over the 1952-68 production life.

Myself and others then made performance tests with the ugly OD's and discs from V-1 thru to the 2nd conversion but not IF stages.

The discs gave a noticable improvement on 10M of about a .5uV improvement for an AM SNR of 10dB. I also tested 10M but dont remember the difference but assume it was less and I didnt have a 6M AD coil.

Others have also reported that stock 60's with discs and out of tolerance resistors replaced (there are always many) were very sensitive even on 6M.

By the time I get thru with a typical 60 rebuild with selected tubes, a 6BY6 in both conversions and a 6GM6 mod for V-1 the 10M AM sensitivity is ~.25uV for a 10dB SNR.  It is one hot mutha and mine spends a lot of time on 10M.

Similar changes are made to the HRO-50, NC-183D and to the older NC-183 where a 6SB7Y is used for the mixer where it is a very decent 6M AM performer.

Carl
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ssbothwell KJ6RSG
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« Reply #6 on: December 29, 2011, 08:44:43 PM »

Well there are always silk capacitors with oxygen free copper leads you could use to

"relieve the music's vibration energy"
and to "decrease the peak feeling sound at high compass and rough quality sound at middle compass"

http://www.thlaudio.com/elnaitme.htm

 Smiley  Huh  Roll Eyes  Grin

wooah. who buys this stuff? i dont understand.

checkout this resistor description:
Quote
Thus far the resistor has been regarded as a necessary evil, something that was needed out of necessity but scorn for its negative impact on the fidelity of the signal.

This has changed with the introduction of the Duelund Coherent Audio Resistors.
When designing these components the task was that the voicecoil of the speaker and the resistor be viewed as a whole rather than two separate entities.

The Duelund CAST proces applied to the top of the line resistor makes it an extraordinary component completely without peers. The result is a resistor which seemingly has no sound of its own and it allows the drivers to perform at their very best.

Duelund's "humble" opinion is that their resistors are the best "bang for the buck" upgrade available.
Simply replace your resistors for unparalled transparency and dynamic ability.
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ke7trp
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« Reply #7 on: December 29, 2011, 08:53:02 PM »

I use Orange drops because I got hundreds and hundreds of them from ham fests new very cheap.  Later, I just purchased the ready made Orange Drop kits from Tubesandmore dot com.  they contain most of the values I would need and seemed to be a decent price.  

The one thing that alot of people complain about with the orange Drops is that the leads come out the bottom.  Most of the time, This means you have to bend the leads around to fit into the location where the tubular cap was.  The radios never look as clean with the Drops.  

I do not care for the Yellow tubular caps.  Some of them are polorized and being a rookie, I have to look over the schematic if its not obvious as to wich way the cap goes.  Then, I had two of them fail on me after a year. I also noticed that the Yellow tubular capacitors have very thin light gauge leads. This is a problem as I like to use needle noise and an iron to wiggle the lead THRU the lug on all connections. With the Yellow caps, This is very difficult as the lead just bends.

I have never had an orange Drop fail after install.

C
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W4AMV
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« Reply #8 on: December 29, 2011, 08:55:11 PM »

Orange drop caps are LARGE devices. Gee Whiz, of course their SRF is not going to be in the GHz range. So lets get calibrated and take some data. I think you all will be surprised. I walked down to the lab, fired up the VNA and measured a .047 uF/ 100 VDC orange cap. The data is attached along with a model of the cap to fit the data. Bottom line, the cap has a series R of ~ 5 ohms and a series inductance of ~ 35 nH. Not bad for a physically large part. Can you do better. Sure! The SRF by the way is ~ 10 MHz, however the series L is small enough that this part will function to 100 MHz.


* An Orange Drop Cap.jpg (71.33 KB, 960x720 - viewed 715 times.)
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ke7trp
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« Reply #9 on: December 29, 2011, 09:04:53 PM »

Great info, Its to bad its for a 100Volt device.

C
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KM1H
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« Reply #10 on: December 29, 2011, 09:11:14 PM »

Great info, Its to bad its for a 100Volt device.

C

Agreed, its not a valid test. In any case "work to xx MHz" is also not a valid argument.
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W4AMV
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« Reply #11 on: December 29, 2011, 09:58:52 PM »

Let me know what would be useful to measure. Its not difficult and I will be glad to combine into one plot and display. I went through this several months ago as I was contemplating what to use on another receiver restore project. I got hooked on this measurement process.... when for giggles and grins I decided to measure a 5 KV plate tuning capacitor at 14 MHz... just to see if it really was 15-150 pF. Can you imagine what the SRF of these monsters are??!! Alarming as it may sound... sometimes we are really tuning a variable L !
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K6JEK
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RF in the shack


« Reply #12 on: December 29, 2011, 10:02:57 PM »

Tests myself and others have run on those to settle arguments show that the values used in that radio are series resonant in the mid HF range and are far from effective in the front end stages. Paper caps were even worse.

National started with all paper, then a mix of paper and mylar, then mylar and disc ceramic. This was over the 1952-68 production life.

Myself and others then made performance tests with the ugly OD's and discs from V-1 thru to the 2nd conversion but not IF stages.

The discs gave a noticable improvement on 10M of about a .5uV improvement for an AM SNR of 10dB. I also tested 10M but dont remember the difference but assume it was less and I didnt have a 6M AD coil.

Others have also reported that stock 60's with discs and out of tolerance resistors replaced (there are always many) were very sensitive even on 6M.

By the time I get thru with a typical 60 rebuild with selected tubes, a 6BY6 in both conversions and a 6GM6 mod for V-1 the 10M AM sensitivity is ~.25uV for a 10dB SNR.  It is one hot mutha and mine spends a lot of time on 10M.

Similar changes are made to the HRO-50, NC-183D and to the older NC-183 where a 6SB7Y is used for the mixer where it is a very decent 6M AM performer.

Carl
Carl, what do you use to replace leaky caps in an HRO-60 or 50?  Do you test disc ceramics?

I have to admit I assume paper caps are bad,  micas are a 50/50 proposition and ceramics are good. Is it time I revised my biases?

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W4AMV
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« Reply #13 on: December 29, 2011, 11:30:47 PM »

Great info, Its to bad its for a 100Volt device.

C

Agreed, its not a valid test. In any case "work to xx MHz" is also not a valid argument.

Not sure what you imply... "is not a valid test". I could bias the unit to 100 V, and re measure its Z vs. frequency. So, what is invalid? As far as work to xx MHz... yes, you would need to investigate if this actual Z vs. frequency is compatible with the remaining network, for example, a series R of 5 ohms is not negligible if I am matching to a 1 ohm device.
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Dave K6XYZ
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« Reply #14 on: December 30, 2011, 02:34:03 AM »

Orange drops used to have a black line on one end that indicated the outer foil.
This lead is supposed to go to the low impedance part of the ckt such as from cathode to ground....the line side goes to ground.
For coupling a plate to the grid of the next stage the line would connect to the plate.

There is a way to determine which lead is the outside foil....it is not always the same one.
Connect a scope to one lead and the ground lead to the other. There will be some noise pickup.
Then reverse the leads....the lead with the highest hum level is the outer foil.

I'm not an audio phool so don't any of youse jokers jump on me about this!  Angry  Roll Eyes
I didn't believe it at first but it's true and does make an improvement in noise.
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kb3rdt
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poop cup


« Reply #15 on: December 30, 2011, 02:35:11 AM »

They are not cheap like a disk but you get what you pay for they have a better tone to audio then others they say. But I think the frequncey so low or high we can't even hear them but you use film cap. looks like yellow shot gun shells.
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The Slab Bacon
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« Reply #16 on: December 30, 2011, 08:49:36 AM »

Dave,
        I have always hooked them up that way! What sucks is like you said, they stopped marking the lead from the outside foil. that was the same reason that I didn't care for the yellow "tootsie roll" polys.

Orange drops are / were usually mylar dialectric, as were just about all of the "epoxy dipped" tubulars, and were immune to moisture / humidity issues, because they had nothing in them that could absorb it.

The problem with the early paper dialectric caps was the paper, as back in the day they used to bleach the paper with sulphuric acid. There was always trace amounts of the stuff left in the paper. Add any amount of moisture and the cap got an identity crisis. It didn't know whether it wanted to stay a capacitor, or change itself into a resistor.

One problem that I ran into with orange drops was that for a while they had tinned steel leads. (as did the tootsie rolls) Because the ODs were radial lead caps, you had to sometimes get "creative" in forming the leads to get everything where you wanted it, and I have had the leads come loose inside the epoxy while twisting and bending them. Even though the tootsie rolls had steel leads, this was much less of a problem due to the fact they were axial leaded caps.

This is a topic I have discussed ad nauseum at the Mid atlantic Antique Radio Club. And here is the main thing you ALWAYS should keep in mind when replacing caps in an old piece of equipment- - - - Whatever kind of cap you decide to use to replace an old waxed paper cap, (mylar, poly, disk, etc) is going to be 1000 times better than the one that you are replacing! ! ! ! ! ! and keeping in mind that disks and modern caps aren't marked for which lead is the outside foil, it really doesn't make much difference when using them for bypassing as the cap itself will keep itself at RF ground! ! ! !

I have repaired 100s of old radios and pieces of ham gear over the years. Unless you are replacing something that is application specific (HV, doorknob, silver-mica etc) It really doesn't for the most part matter what you use, so look for deals and dont pay bazillions of bux for fancy-assed caps that you dont really need! ! ! ! ! ! ! ! ! ! ! !  
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The Slab Bacon
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« Reply #17 on: December 30, 2011, 08:52:37 AM »

I have an HRO-60 to go through. What caps to use is the question.

I used to use orange drops because they have a good reputation and seem more period appropriate. But somewhere along the line, I think it was an SX-62, I gave up and switched to yellow poly's because they fit in the crowded wiring. They are smaller and have axial leads. I have to admit, I don't like they way they look.  

Is there any technical argument for orange drops or is it just aesthetics?  And no, I'm not ready to do any capacitor re-stuffing.


Oh, yea, for what it's worth those white tubular caps are quite often early generation mylar dialectrics and usually dont go bad. You may want to remove 1 and bust it open to see what the dialectric is.



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WA1GFZ
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« Reply #18 on: December 30, 2011, 09:34:38 AM »

somebody said the ESR measures around 5 ohms. In a high Z tube circuit this is nothing but I want to roll on the ground when I see them used to bypass a low Z solid state final.
The performance limit of all these foil caps is the method the leads are attached to the foils. This usually adds some series inductance.
Sanders Associates made their own foil caps that were terminated in a way that reduced the series L to a very low inductance. I saw them blow away OJ caps when we were EMI testing a high power deice system years ago.
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Bill, KD0HG
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« Reply #19 on: December 30, 2011, 09:39:57 AM »

In older radios, like my 1939 airplane dial Sky Buddy, I have removed the defective original wax/paper caps, heated them up and removed the guts. Then I insert a small modern metalized film cap into the tube and resealed the ends with some of the saved wax from the old caps. I have used beeswax as well.

You can usually rebuild the old metal can caps like those in Command sets in a similar way.

Cosmetically perfect, and I have always liked the performance of metalized film caps. They are compact. Any technical magic to Orange drop or Black Beauty caps is strictly urban legend, IMO.
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W4AMV
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« Reply #20 on: December 30, 2011, 09:59:50 AM »

somebody said the ESR measures around 5 ohms. In a high Z tube circuit this is nothing but I want to roll on the ground when I see them used to bypass a low Z solid state final.
The performance limit of all these foil caps is the method the leads are attached to the foils. This usually adds some series inductance.
Sanders Associates made their own foil caps that were terminated in a way that reduced the series L to a very low inductance. I saw them blow away OJ caps when we were EMI testing a high power deice system years ago.

Correct! Yes, I measured 5 ohms series R on this 100 V OD, and that is awful for Solid State work. I guess the point of this thread at least from my perspective, if at all possible,  when these WISE tails rise up from the dungeons... let's measure. Again... In GOD we trust, all others bring data.  Smiley
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The Slab Bacon
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« Reply #21 on: December 30, 2011, 10:43:33 AM »

That is all well and true for modern solid state stuff, but.................

This thread was originally started about an HRO-60 which is neither modern or solid state  Grin  Grin

I wonder if they even knew what ESR was back then  Huh  Huh
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Todd, KA1KAQ
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« Reply #22 on: December 30, 2011, 11:06:34 AM »

And to the original question posed, the only technical advantage to using them was better reliability and higher quality some years back, when the Asian offerings were questionable at best.

As for any other reason, it's been batted around here numerous times. Until recently, ODs were manufactured right here in the good ol' USA, so it was an opportunity to support a 'local' supplier. They are also great quality, offered in a large variety of sizes and voltages needed for old equipment. They still are made here, but on a limited basis now, mainly custom runs. The bulk are now made in China.

The biggest drawback is the radial lead arrangement, not well-suited for all environments. Though they do have long enough leads, this combined with the size of the higher voltage pieces makes them difficult to fit into some rigs. This does not lend them well to re-stuffing old caps, of course. And if you're old like Carl, bright colors make you dizzy.  Grin

Never been inside a HRO-60, but the timeframe is right. They'd probably be right at home, especially if you had some of the older Sprague-labeled units.
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k4kyv
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Don
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« Reply #23 on: December 30, 2011, 12:40:59 PM »

I usually use orange drops or disc ceramics, depending on their function, to replace old-fashioned wax-paper caps. I try to find new disc ceramics to replace failed ones, and good micas to replace failed micas.

I have boxes full of n.o.s. and salvaged capacitors of every description.  I usually just try to find something that is compatible in my junkbox that checks good, using a capacitor checker to test for leakage or else the brute-force method of DC power supply and mirco-ammeter (hoping the cap doesn't abruptly short out while under test), because I usually need it RIGHT THEN, not a few days later when one I ordered online comes in.  If I need it immediately and can't find a replacement, I try the local electronics store (not Radio Shack), but there is only about a 50-50 chance they'll carry it. I haven't had a great deal of problem with replaced caps crapping out, but that could explain some of the intermittents I seem to be plagued with.

Carbon composition resistors seem to be a greater problem than the old wax caps.  I'd say over 75% of the ones I check, whether residing in existing equipment or still n.o.s., have drifted in value, anywhere from 30% to over 100%. In non-critical parts of the circuit, I rarely see any improvement when replacing one of these with one of the proper value, so I just  leave them alone. In critical applications I may buy a new one if I can't find one that has not drifted.

Old mica caps bear watching, too.  Disc ceramics seem to hold their values, but I have had quite a few of these to short out (that's why I use two in series for the blocking cap between plate and mechanical filters in my 75A-4).

Like Bill, in the relatively rare event when I am interested in preserving the appearance of a piece of antique equipment, I re-stuff the caps, even to the point of re-using the original leads or same size wire (the newer caps tend to have smaller gauge wire, which not only detracts from the appearance; it is often too flimsy to hold the re-stuffed capacitor in place).

For replacing the old body-tip-dot resistors, if I want to maintain the original appearance and cannot find an exact replacement, I take the ohmmeter and look for one the proper resistance value, regardless of its nominal value.  I have found that even the drifted ones are fairly stable; maybe they have gone through most of their drift and settled down to their new value and will stay there. One could even re-paint the body, tip and dot to indicate the new nominal value, although  to date I haven't gone that far.

I tend to stay with carbon comps for anything that handles considerable power, since I have found the newer film resistors to be delicate, often opening up at a relatively slight overload or an accidental short with a meter test probe.

I replaced many of the by-pass caps in my 75A-4 with orange drops, and several of the little red mica coupling caps with newer micas.  It would be tremendously laborious to replace all the 1/2-watt carbon comp resistors, but the day may come when that's the only way to keep some of this older stuff going, assuming we can still find working replacement tubes by then.
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Don, K4KYV                                       AMI#5
Licensed since 1959 and not happy to be back on AM...    Never got off AM in the first place.

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K6JEK
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RF in the shack


« Reply #24 on: December 30, 2011, 01:30:14 PM »

...
 Until recently, ODs were manufactured right here in the good ol' USA, so it was an opportunity to support a 'local' supplier. They are also great quality, offered in a large variety of sizes and voltages needed for old equipment. They still are made here, but on a limited basis now, mainly custom runs. The bulk are now made in China.
...

Anyone know anything about the American Capacitor Corporation?  Looks like  they make caps in the US of A. and  not hand rolled, bees wax and paper sonic superiority stuff. The first distributor I checked will accept orders of $30 or more.  I may go out on a limb and buy some of their stuff  (if I can) just to avoid filling the HRO-60 with Chinese parts. Yes, I know this makes little difference in the big picture but at least I won't be thinking about China every time I turn the big tuning knob.

http://www.americancapacitor.com/

pictures

http://www.americancapacitor.com/case.htm

or maybe these guys

http://www.filmcapacitors.com/

I can't bring myself to re-stuff caps. Bill and Don are some kind of restoration heroes for doing it.
 

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