Why replace electrolytics with tantalum in Hi-Fi Mod?

[Onelasttime]

So I am collecting capacitors to recap about 5 different radio's. I have looked at Gold Fingers modifications for HiFi for more than one chassis. He sure does seem to like tantalums. In at least two radio's of mine he recommends a 16V Tantalum at 1uf to 2uf but in each case the OEM used 50V electrolytic in the .22uf and 1uf range.

I was always taught to devalue tantalum because they fail at .1 to 1% the closer to the specified rating they are run at. That assumes you do not get them hot either. On top of that when they fail they normaly fail in a short. To obey the Mil-Spec. that Kemet recommends on their sight I would need to run a 85-100V tantalum. That would be physically huge only available in axial when I need a radial and it would put more volume and mass in the signal path. I do not see how that would help the audio signal at all?

He also recomends mylar caps but again in 1uf to 2uf rating the smallest mylar or metalized film cap is 7.5mm on leading spacing attempting to replance parts that have 1.5mm to 2mm lead spacing.

I thought about using a film cap to bypass the best electrolytic I can find for the audio signal path but again space is an issue and you normally have to parallel an lytic with a film cap of at least 20% of the lytics capacitance to see any improvement.

In one case his recommendation is replacing a 50V .22uf lytic with a 16V 2.2uf that is a HUGE increase in capacitance and a huge decrease in the voltage rating.

Has anyone tried just increasing the capacitance but staying with the recommended voltage and capacitor type?

I thought about using some Panasonic stacked film caps but the difference in size is HUGE. If I tried to fit a film cap with LS of 7.5mm into a 2mm LS hole I would have to leave quite a bit of lead exposed to keep the huge wide head of the cap from touching. No way I can put it down close tot he board. I would imagine this would open the door for stray rf and for vibration damage long term?

My thoughts which I welcome correction on are that top of the line audio grade electrolytics are far better than they where 18 years ago and just increasing from the .22uf to the recommended 2.2uf should make a world of difference. After all the fidelity of a CB or Export radio is not remotely close to a home stereo amplifier or eq where a film cap in the signal path makes perfect sense. So is it worth my time to shoe horn film caps in and or is it largely a waste of time and really just a cap value issue more than material choice?

 

[Captain Kilowatt]

Sounds like this Gold Finger guy is trying to bedazzle and bull shit people. I would never put a 16 volt cap in a radio as it is simply too close to the supply voltage however if it is purely as an audio coupling cap then OK as long as the DC supply voltage is not across it. IMHO there is no sense in putting lipstick on a pig. In the end it is still a pig. Go with decent electrolytics that will fit unless the original is a tantalum in which case use a tantalum in it's place.

 

[543_Dallas]

I use electrolytic caps for these types of mods. I've even replaced stock mylar caps with bipolar electrolytics. The capacitance, polarity and voltage rating is all I worry about anymore.

 

[cbphreaker]

Audiophiles consider the D.A. and ESR when choosing to use Tant. over Elec.

The claim is some amount of audio will cause the resistance of the cap. to modulate which in turn will cause the plates of the cap to vibrate at an audio rate. The theory is the vibration of the plates colors the sound. Since tant, caps generally are considered low ESR they suffer less from the "microphonics." then an equivalent electro.

This may shed more light and cause some discussion:

http://www.bext.com/replacing-passive-components-to-improve-sound-quality/

 

[Captain Kilowatt]

Audiophiles consider the D.A. and ESR when choosing to use Tant. over Elec.

The claim is some amount of audio will cause the resistance of the cap. to modulate which in turn will cause the plates of the cap to vibrate at an audio rate. The theory is the vibration of the plates colors the sound. Since tant, caps generally are considered low ESR they suffer less from the "microphonics." then an equivalent electro.

This may shed more light and cause some discussion:

http://www.bext.com/replacing-passive-components-to-improve-sound-quality/

Yes and audiofools also think that copper free speaker wires sound better than plain old regular copper wires and that gold plated AC outlets work better than regular brass outlets. Sometimes those people astound me in what they can come up with. I really should open an audio supply store catering to those audiofools and make a ton of money off of them but I have a conscience.

 

[543_Dallas]

The same guys might even think a toob type linear and oxygen free coax has better sounding audio.

 

[sixstrings]

I gotta stop you two right here. I am a professional musician not a home guitarist and I can tell right here and now yes there is a difference. Just because you cant hear it does not mean it doesnt exist!

I am offended by your statment of"audio-fools" as a mater of fact you just bagged on your favourite musical artist or anyone in your family that plays an instrument.
I see your a broadcast engineer? I guess you make a living from the fact there are people in this world who can hear something that you CANT and not only can you not hear it your not even open minded enough to even think that some might be-able to do something you cant. And let me school ya -they can.

I dont know much about radio and I dont claim to nor di i really care but about 1 month ago I joined my citys local ham club. do you know the fist thing I learned in my test prep class? Ill bet you forgot. Code of conduct. You need to get back to basics pal.

In my eyes you went from Capt. kilowatt to Capt Milliwatt

"click" -did you hear that?t -I just hung up the internet on you

goodbye please

 

[543_Dallas]

The comment I made was in regard to cb/amateur radio. The tube comment was for RF amplifiers not audio ampifiers.

 

[Mudduckmobile]

The same guys might even think a toob type linear and oxygen free coax has better sounding audio.

ox-free coax = less money in your pocket more money in the pocket of the seller....JMHO
And for what it's worth, I think I may have heard OL'Gordo (West) say on "This week in Ham" that ox-free is a waste of $. But, Then What does old G. West know?????

 

[Robb]

When critical frequency accuracy is required, a tantalum is used. You see them mostly in PLL circuits, but not exclusively. Accuracy with frequency synthesis is critical. Tantalum caps are not invulnerable either, they are quite sensitive to stresses and abuses and will break down. More suspect of failure in an audio circuit than any other place.

 

[543_Dallas]

ox-free coax = less money in your pocket more money in the pocket of the seller....JMHO
And for what it's worth, I think I may have heard OL'Gordo (West) say on "This week in Ham" that ox-free is a waste of $. But, Then What does old G. West know?????

I made up the oxygen free coax but that could be a real thing. On the original topic I believe there are caps that are better suited for audio but when we're modifying a receiver in a CB radio they aren't worth the extra cost. If you want the best you would be better off investing in another receiver.

 

[Mudduckmobile]

I made up the oxygen free coax but that could be a real thing. On the original topic I believe there are caps that are better suited for audio but when we're modifying a receiver in a CB radio they aren't worth the extra cost. If you want the best you would be better off investing in another receiver.

I do beleave it was on "ham Nation" #267 that Gordon West was talking about OX-COAX, I could be wrong...I don't want to watch 1:12:41hrs of rerun to check...

UP DATE: 543_DALLAS, I was wrong! I just reviewed Ham Nation # 267. I was wrong. Amanda Alden was talking with George Thomas @ 1:08:54 about ox-free speaker wire not coax. My bad.

 

[Captain Kilowatt]

I gotta stop you two right here. I am a professional musician not a home guitarist and I can tell right here and now yes there is a difference. Just because you cant hear it does not mean it doesnt exist!

I am offended by your statment of"audio-fools" as a mater of fact you just bagged on your favourite musical artist or anyone in your family that plays an instrument.
I see your a broadcast engineer? I guess you make a living from the fact there are people in this world who can hear something that you CANT and not only can you not hear it your not even open minded enough to even think that some might be-able to do something you cant. And let me school ya -they can.

I dont know much about radio and I dont claim to nor di i really care but about 1 month ago I joined my citys local ham club. do you know the fist thing I learned in my test prep class? Ill bet you forgot. Code of conduct. You need to get back to basics pal.

In my eyes you went from Capt. kilowatt to Capt Milliwatt

"click" -did you hear that?t -I just hung up the internet on you

goodbye please

Oh look.....another newbie that just joined up and got all butt hurt because he saw someone on the internet post something he does not agree with and decided the best course of action was to insult the admin that posted it. Not a great move I must say. I used the term audiofool and I meant it. Despite all the mumbo-jumbo about electro-chemical properties there is no scientific proof that it makes any difference. I worked under someone who was arguably the best audio/RF engineer east of Toronto and he would say the same thing I had to say about oxygen free cable and gold plated AC outlets. Just because you disagree with something does not give you the right to start a bitch-fest about it...........especially as a newbie and ESPECIALLY to an administrator on this forum. As for code of conduct....news flash....we are not on the air which is what the code of conduct was all about and YOU should think about your own conduct. Pretty easy to mouth-off when you are hiding behind an IP proxy-server like IPVanish. Now think about how you want to respond and see if you can anticipate my reaction. Think carefully.

 

[Robb]

Matter of fact, I had to replace a tantalum cap today in a local op's radio. A Ranger/Freedom One, which uses the same board as a Galaxy 959. The audio had fallen way down in output level.

Checked the tantalum from that circuit on a ESR tester. This 2.2uF/16v cap showed a series resistance on 10+ ohms. Waaay too high. Also upgraded it to a 25v, since 16v is too small. That, and that is the only voltage I had in that value - lol. Also had to replace the TA7222AP audio amp.

Short a tantalum once or twice, and they cannot be trusted to continue working. Fussy and expensive, they are designed in and one of the first area I will look at in a circuit if there is one in it. Ounce of prevention, and sometimes the cure . . .

 

[unit_399]

All this talk about hi-fi cb is just that...TALK. Sure, you can modify a modulator to produce a more natural sounding frequency response. And ... you can open up the bandwidth to get that "hi-fi" sound. But ........ who is ever going to hear it ?? The majority of cb receivers are so bandwidth restricted by their filtering and diode detectors that any audio improvements can't be heard anyway. So, what are these improvements worth if no one can hear them ????
If "audiophiles" can post mods that make a CB transmit HI-FI audio, why don't they post receiver mods that would allow listeners to hear them ???

Sorry, but I use CB radio to communicate. I could care less whether my voice sounds natural or not. All I care about is that the listener understands EVERYTHING I'm saying. To me, this hi-fi stuff is just a total waste of time.

- 399