Hi all,
I think it might be a good idea to replace all the tantalum caps used
for coupling and decoupling purposes is Uher tape deck I'm fixing up
with new ones as I gather tants can go flaky over time. Now I have an
awful lot of these caps in NOS - see link - which I'd like to use up
if possible. I can't think of any reason why they shouldn't be
perfectly usable - can you? They're polysomething film types I
believe:
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTjegZQJ94Ng9dxJVpN4ISUbqPxfF_jFdBFCQ&s
Will I be okay to use them?
Hi all,
I think it might be a good idea to replace all the tantalum caps used
for coupling and decoupling purposes is Uher tape deck I'm fixing up
with new ones as I gather tants can go flaky over time.
Cursitor Doom <cd@notformail.com> wrote:
Hi all,
I think it might be a good idea to replace all the tantalum caps used
for coupling and decoupling purposes is Uher tape deck I'm fixing up
with new ones as I gather tants can go flaky over time.
Is there any evidence of failing capacitors?
On Mon, 19 Jan 2026 23:45:30 +0000, Cursitor Doom <cd@notformail.com>
wrote:
Hi all,
I think it might be a good idea to replace all the tantalum caps used
for coupling and decoupling purposes is Uher tape deck I'm fixing up
with new ones as I gather tants can go flaky over time. Now I have an
awful lot of these caps in NOS - see link - which I'd like to use up
if possible. I can't think of any reason why they shouldn't be
perfectly usable - can you? They're polysomething film types I
believe:
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTjegZQJ94Ng9dxJVpN4ISUbqPxfF_jFdBFCQ&s
Will I be okay to use them?
No. The caps in the photo are polycarbonate or polyester capacitors,
not tantalum: ><https://www.jameco.com/Jameco/workshop/ProductNews/different-types-of-capacitors.png>
I like to buy replacement recap kits on eBay (because I'm lazy). So
far, they all worked as expected. Where I had problems was when I
tried to save money with used parts or salvaged parts, or didn't
bother testing the replacement caps before soldering.
Hi all,
I think it might be a good idea to replace all the tantalum caps used
for coupling and decoupling purposes is Uher tape deck I'm fixing up
with new ones as I gather tants can go flaky over time. Now I have an
awful lot of these caps in NOS - see link - which I'd like to use up
if possible. I can't think of any reason why they shouldn't be
perfectly usable - can you? They're polysomething film types I
believe:
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTjegZQJ94Ng9dxJVpN4ISUbqPxfF_jFdBFCQ&s
Will I be okay to use them?
On 2026-01-19 18:45, Cursitor Doom wrote:
Hi all,You should be fine replacing the coupling caps.
I think it might be a good idea to replace all the tantalum caps used
for coupling and decoupling purposes is Uher tape deck I'm fixing up
with new ones as I gather tants can go flaky over time. Now I have an
awful lot of these caps in NOS - see link - which I'd like to use up
if possible. I can't think of any reason why they shouldn't be
perfectly usable - can you? They're polysomething film types I
believe:
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTjegZQJ94Ng9dxJVpN4ISUbqPxfF_jFdBFCQ&s
Will I be okay to use them?
Whether it works on the decaps sepends on whether the circuit requires
the higher ESR of the tants for stability. Some do, some don't.
Cheers
Phil Hobbs
On Tue, 20 Jan 2026 17:32:29 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
Cursitor Doom <cd@notformail.com> wrote:
Hi all,
I think it might be a good idea to replace all the tantalum caps used
for coupling and decoupling purposes is Uher tape deck I'm fixing up
with new ones as I gather tants can go flaky over time.
Is there any evidence of failing capacitors?
Just generally poor audio which I can't pin down to a specific stage. Tantalums are not noted for their reliability and seem to be the prime suspect in cases like this.
<pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2026-01-19 18:45, Cursitor Doom wrote:
Hi all,You should be fine replacing the coupling caps.
I think it might be a good idea to replace all the tantalum caps used
for coupling and decoupling purposes is Uher tape deck I'm fixing up
with new ones as I gather tants can go flaky over time. Now I have an
awful lot of these caps in NOS - see link - which I'd like to use up
if possible. I can't think of any reason why they shouldn't be
perfectly usable - can you? They're polysomething film types I
believe:
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTjegZQJ94Ng9dxJVpN4ISUbqPxfF_jFdBFCQ&s
Will I be okay to use them?
Whether it works on the decaps depends on whether the circuit requires
the higher ESR of the tants for stability. Some do, some don't.
Thanks, Phil. You're the word of God AFAIC. :-)
I'm also grateful to our other contributors of course. We often
disagree over fine points like this and sometimes it's impossible to
know whose approach is most appropriate in any given circumstance.
Cursitor Doom <cd@notformail.com> wrote:
On Tue, 20 Jan 2026 17:32:29 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
Cursitor Doom <cd@notformail.com> wrote:
Hi all,
I think it might be a good idea to replace all the tantalum caps used
for coupling and decoupling purposes is Uher tape deck I'm fixing up
with new ones as I gather tants can go flaky over time.
Is there any evidence of failing capacitors?
Just generally poor audio which I can't pin down to a specific stage.
Tantalums are not noted for their reliability and seem to be the prime
suspect in cases like this.
If the DC voltages on the various transistors are correct, the volume
control isn't noisy and there is no hum when working from the mains, I
would leave the capacitors alone and look elsewhere for the problem.
On Wed, 21 Jan 2026 20:27:07 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
Cursitor Doom <cd@notformail.com> wrote:
On Tue, 20 Jan 2026 17:32:29 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
Cursitor Doom <cd@notformail.com> wrote:
Hi all,
I think it might be a good idea to replace all the tantalum caps used >>> >> for coupling and decoupling purposes is Uher tape deck I'm fixing up
with new ones as I gather tants can go flaky over time.
Is there any evidence of failing capacitors?
Just generally poor audio which I can't pin down to a specific stage.
Tantalums are not noted for their reliability and seem to be the prime
suspect in cases like this.
If the DC voltages on the various transistors are correct, the volume >>control isn't noisy and there is no hum when working from the mains, I >>would leave the capacitors alone and look elsewhere for the problem.
I'm going to have to start from scratch again, anyway. The reference
tape I made which I had implicit faith in despite not checking it for >fidelity first turned out to have every bit as much distortion as that
which the fault itself was giving rise to. Assumptions. The mother of
all fuck-ups!
So now it's back to square 1. :-(
On Wed, 21 Jan 2026 22:27:23 +0000, Cursitor Doom <cd@notformail.com>
wrote:
On Wed, 21 Jan 2026 20:27:07 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
Cursitor Doom <cd@notformail.com> wrote:
On Tue, 20 Jan 2026 17:32:29 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
Cursitor Doom <cd@notformail.com> wrote:
Hi all,
I think it might be a good idea to replace all the tantalum caps used >>>> >> for coupling and decoupling purposes is Uher tape deck I'm fixing up >>>> >> with new ones as I gather tants can go flaky over time.
Is there any evidence of failing capacitors?
Just generally poor audio which I can't pin down to a specific stage.
Tantalums are not noted for their reliability and seem to be the prime >>>> suspect in cases like this.
If the DC voltages on the various transistors are correct, the volume >>>control isn't noisy and there is no hum when working from the mains, I >>>would leave the capacitors alone and look elsewhere for the problem.
I'm going to have to start from scratch again, anyway. The reference
tape I made which I had implicit faith in despite not checking it for >>fidelity first turned out to have every bit as much distortion as that >>which the fault itself was giving rise to. Assumptions. The mother of
all fuck-ups!
"That which is obviously correct, beyond any need of checking, is
usually the problem". I forgot where I stole that.
If you seem to have hit a wall, and can progress no further along the
current line of reasoning, then stop and check your assumptions. One
or more assumptions will likely be wrong. If that doesn't yield
results, verify your procedures to make sure you're not dividing by
zero. If everything sounds distorted, remove your ear plugs, clean
the wax from your ears, and turn off anything that might be producing
out of band noises, such as ultrasonics or ringing.
So now it's back to square 1. :-(
The number 1 squared is still equal to 1. It also stays at 1 no
matter how many times you square it. No matter how many times you
repeat the mistake hiding in square 1, your answer will remain
unchanged and wrong.
Tantalum caps do cause problems. However, the problems appear as
noises, not distortion.
"Tantalum capacitor causing scratchy noise in phono input?" ><https://www.facebook.com/groups/242963289391919/posts/2733303303691226/>
If you want to go hunting for noisy components, spray the suspect with
freeze spray. If the noise disappears, you've found the culprit or at
least localized the cause. ><https://www.google.com/search?q=electronic%20freeze%20spray&udm=2>
If you want to go hunting for noisy components, spray the suspect with >>freeze spray. If the noise disappears, you've found the culprit or at >>least localized the cause. >><https://www.google.com/search?q=electronic%20freeze%20spray&udm=2>
Yeah, I've had some good results with that stuff in the past. However,
I've only used it when a fault develops after the equipment's been
switched on for a while. I then spray it to see if it 'cures' the
problem. Not sure how much use it would be in this case where the
fault is present right from switch on. :-/
On Thu, 22 Jan 2026 12:36:39 +0000, Cursitor Doom <cd@notformail.com>
wrote:
If you want to go hunting for noisy components, spray the suspect with >>>freeze spray. If the noise disappears, you've found the culprit or at >>>least localized the cause. >>><https://www.google.com/search?q=electronic%20freeze%20spray&udm=2>
Yeah, I've had some good results with that stuff in the past. However,
I've only used it when a fault develops after the equipment's been
switched on for a while. I then spray it to see if it 'cures' the
problem. Not sure how much use it would be in this case where the
fault is present right from switch on. :-/
Freeze spray works well with semiconductors and not so well with
capacitors and resistors. The big problem is condensation. If you
spray a PCB (printed circuit board) with freeze spray, moisture will
condense on the PCB. For any PBC or components that are not water
tolerant, it will cause the circuitry to fail until you dry off the
PCB. You can do that with a hot air gun or oven to accelerate
evaporation.
Pre-heating the PCB before testing with freeze spray, is a bad idea.
Most common components are not rated for thermal shock. Cracking
components, such as MLCC caps, are possible. If you've heated the PCB
to accelerate evaporation, I would let the PCB temperature drop to
room temperature before repeating the freeze spray test.
You're not looking for a "cure" for the distortion problem. You're
looking for something that causes the distortion to CHANGE. It
doesn't matter if the distortion becomes better or worse. If the
component is sensitive to changes in temperature, it's a likely
culprit worthy of replacement.
Hint: Make a shield. Punch a hole in a sheet of cardboard or
plastic. Place the hole over the likely culprit and spray it. The
idea is to only apply freeze spray to one component at a time.
On Thu, 22 Jan 2026 10:41:41 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:
On Thu, 22 Jan 2026 12:36:39 +0000, Cursitor Doom <cd@notformail.com> >>wrote:
If you want to go hunting for noisy components, spray the suspect with >>>>freeze spray. If the noise disappears, you've found the culprit or at >>>>least localized the cause. >>>><https://www.google.com/search?q=electronic%20freeze%20spray&udm=2>
Yeah, I've had some good results with that stuff in the past. However, >>>I've only used it when a fault develops after the equipment's been >>>switched on for a while. I then spray it to see if it 'cures' the >>>problem. Not sure how much use it would be in this case where the
fault is present right from switch on. :-/
Freeze spray works well with semiconductors and not so well with
capacitors and resistors. The big problem is condensation. If you
spray a PCB (printed circuit board) with freeze spray, moisture will >>condense on the PCB. For any PBC or components that are not water >>tolerant, it will cause the circuitry to fail until you dry off the
PCB. You can do that with a hot air gun or oven to accelerate
evaporation.
Pre-heating the PCB before testing with freeze spray, is a bad idea.
Most common components are not rated for thermal shock. Cracking >>components, such as MLCC caps, are possible. If you've heated the PCB
to accelerate evaporation, I would let the PCB temperature drop to
room temperature before repeating the freeze spray test.
I think I'd just wait for ambient temp to do its work, tbh.
You're not looking for a "cure" for the distortion problem. You're
looking for something that causes the distortion to CHANGE. It
doesn't matter if the distortion becomes better or worse. If the
component is sensitive to changes in temperature, it's a likely
culprit worthy of replacement.
Good point! Thanks, Jeffrey. You're right of course (as ever).
Hint: Make a shield. Punch a hole in a sheet of cardboard or
plastic. Place the hole over the likely culprit and spray it. The
idea is to only apply freeze spray to one component at a time.
I'd go for the mask idea in the endgame as it were, but I'd just have
a spray around various small areas containing several components
first, otherwise the process would take too long. I like to zoom
in.....
:)
On Tue, 20 Jan 2026 09:05:34 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:
On Mon, 19 Jan 2026 23:45:30 +0000, Cursitor Doom <cd@notformail.com>
wrote:
Hi all,
I think it might be a good idea to replace all the tantalum caps used
for coupling and decoupling purposes is Uher tape deck I'm fixing up
with new ones as I gather tants can go flaky over time. Now I have an
awful lot of these caps in NOS - see link - which I'd like to use up
if possible. I can't think of any reason why they shouldn't be
perfectly usable - can you? They're polysomething film types I
believe:
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTjegZQJ94Ng9dxJVpN4ISUbqPxfF_jFdBFCQ&s
Will I be okay to use them?
No. The caps in the photo are polycarbonate or polyester capacitors,
not tantalum:
<https://www.jameco.com/Jameco/workshop/ProductNews/different-types-of-capacitors.png>
I like to buy replacement recap kits on eBay (because I'm lazy). So
far, they all worked as expected. Where I had problems was when I
tried to save money with used parts or salvaged parts, or didn't
bother testing the replacement caps before soldering.
Yeah, I'm aware they're different types, Jeff. But AI said it would be
fine to swap tants for polys in an audio amp chain of stages. However,
On 2026-01-20 3:33 p.m., Cursitor Doom wrote:
On Tue, 20 Jan 2026 09:05:34 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:
On Mon, 19 Jan 2026 23:45:30 +0000, Cursitor Doom <cd@notformail.com>
wrote:
Hi all,
I think it might be a good idea to replace all the tantalum caps used
for coupling and decoupling purposes is Uher tape deck I'm fixing up
with new ones as I gather tants can go flaky over time. Now I have an
awful lot of these caps in NOS - see link - which I'd like to use up
if possible. I can't think of any reason why they shouldn't be
perfectly usable - can you? They're polysomething film types I
believe:
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTjegZQJ94Ng9dxJVpN4ISUbqPxfF_jFdBFCQ&s
Will I be okay to use them?
No. The caps in the photo are polycarbonate or polyester capacitors,
not tantalum:
<https://www.jameco.com/Jameco/workshop/ProductNews/different-types-of-capacitors.png>
I like to buy replacement recap kits on eBay (because I'm lazy). So
far, they all worked as expected. Where I had problems was when I
tried to save money with used parts or salvaged parts, or didn't
bother testing the replacement caps before soldering.
Yeah, I'm aware they're different types, Jeff. But AI said it would be
fine to swap tants for polys in an audio amp chain of stages. However,
You are aware that often when AI doesn't actually know the answer it
simply hallucinates something. And it doesn't TELL you that it doesn't
know so how do you trust anything produced by it.
I often see Google AI suggestions that are total crap - repeats of the
top ten sites, which are mirrors of each other. Back to Duck Duck form
my search engine!
Try using data sheets and learning about the differences between
capacitors or you will always be just another hack.
John :-#(#
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