Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dude on June 07, 2024, 03:21:51 pm
-
On a PCB bd can a small low 15v 10uf E-cap be replaced with a non-polarity ceramic cap, if on the bd there are “no polarity marks (+ and -).”
-
Yes. Any e-cap can be replaced with an equal value/voltage rating cap.
-
Yes. Any e-cap can be replaced with an equal value/voltage rating cap.
Sluckey, thank you very much. I posted the real question in effects but not much in answers there. The schematic designates a 10/16v cap, has a + on one lead on the schematic but “is crossed out” on the schematic, looks like when it was originally written too. No marks on the bd.
-
Here a shot of the cap, crossed out..? Never seen this, so non polarity can be used here. C1
-
cap, crossed out..?
The schematic you posted is blurry. Here are some suggestions for you. GIYF
https://www.google.com/amp/s/www.electricaltechnology.org/2019/09/capacitor-symbols.html/amp (https://www.google.com/amp/s/www.electricaltechnology.org/2019/09/capacitor-symbols.html/amp)
(Looks like Japanese symbol for polarised e-cap to my ageing retina)
-
Wow, l saw the symbol on the schematic l’m dealing with. So, confused. Bottom line: this is a pedal, a friend bought this boss blues driver mod, asked me to do it. I notice the poly film caps replacing e- caps, l figured Fromel Electronics knows their stuff, so the questions. Would you hesitate to follow his instructions replacing a few e-caps with his ploy film? I notice not all e-caps on the full schematic are marked like that, just some and those are the ones he sent in his mod kit.
If you hit the link, schematic gets clear better, just view it, not download
-
You're obsessing over nothing. Read reply #1 again.
-
They might be tantalum caps. I've built some stompboxes that use tantalum in the audio signal.
That would explain why some polarized caps in that schematic seem to look different.
-
that symbol was pretty common in SS schematics
-
Hey, not obsessing, just Tubeswell suggested the symbol was polarized. Ok, l figured before l posted no issue, but l was just asking for a second opinion.
Done, over, l’ll do the mod.
Thanks again
-
Yes. Any e-cap can be replaced with an equal value/voltage rating cap.
Sluckey, thank you very much. I posted the real question in effects but not much in answers there. The schematic designates a 10/16v cap, has a + on one lead on the schematic but “is crossed out” on the schematic, looks like when it was originally written too. No marks on the bd.
With all due respect, the question as posted in Effects was difficult to grasp. Also in the guitar pedal world there's various types low voltage caps, that aren't used in tube amp applications.
-
And if you really want to cover your bases, you can use a bipolar e-cap!
I'm with Sluckey on this one. As long as your capacitance and voltage ratings are good, a film cap can reliably replace an electrolytic cap.
-
My assumption is that a 10uF 16V film cap would have too large a form factor to replace a similarly rated ecap?
-
And if you really want to cover your bases, you can use a bipolar e-cap!
Sounds like you're suggesting that his ball club recruit my mother.
Dave
-
If the small schematic you posted is the schematic that correspond to your board
the + of the e-cap is connected to the pin #1 (the emitter) of the transistor
don't you see it ?
(https://i.imgur.com/8NDw1WG.jpeg)
the plus symbol is below zero by 10/16
follow the path from the empty hole wher there was the capacitor till the 10K resistor and you know which is the side to connect because the emitter (pin #1 of the transistor) is connected to ground via that 10K resistor (R2)
Franco
-
If the small schematic you posted is the schematic that correspond to your board
the + of the e-cap is connected to the pin #1 (the emitter) of the transistor
don't you see it ?
(https://i.imgur.com/8NDw1WG.jpeg)
the plus symbol is below zero by 10/16
follow the path from the empty hole wher there was the capacitor till the 10K resistor and you know which is the side to connect because the emitter (pin #1 of the transistor) is connected to ground via that 10K resistor (R2)
Franco
Franco, YES I see it, thanks. I understand how to connect e-caps from a schematic, you’d have to read all the posts to understand my question about the schematic. I see the +. But notice it’s marked different then other cap symbols on this same schematic, (marks across the = lines). Making me believe a non-polarized cap can be used there. But l’ll run with what Sluckey affirmed.
-
Is that a Boss schematic? It’s not crossed out, that’s just the symbol they used for elecrolytics.
In any case, you can use a film cap there.
-
Making me believe a non-polarized cap can be used there. But l’ll run with what Sluckey affirmed.
Yes you can use a film cap there - agree with Steve and everyone else. Bear in mind the schematic says 10uF (but IMO overkill).
Needless to say that if you find that the <1uF film cap that you are likely to find in an appropriately sized package sounds a bit thin, you can (if you want) use a polarised e-cap in the 5 to 10uF range. In which case, the '+' end has to be oriented towards the higher +ve source voltage (in this case, the NPN emitter). You can also use a bipolar e-cap, or not. As always, YMMV
-
If you ever find yourself unsure of polarity just measure. In scenarios like this where you have a working circuit that you're swapping values in it is very easy to determine which is the higher voltage side and thus the orientation of a polarized cap.
-
I see the +. But notice it’s marked different then other cap symbols on this same schematic, (marks across the = lines). Making me believe a non-polarized cap can be used there. But l’ll run with what Sluckey affirmed.
There are only two capacitor symbols used on the schematic, non-polar and polar.
(https://www.experimentalistsanonymous.com/diy/Schematics/Distortion%20Boost%20and%20Overdrive/BOSS%20BD-2.gif)
-
As Merlin says and as Tubeswell pointed to
That simbol is a version used in Japan (and may be in other places) to indicate a polarized cap
(https://i.imgur.com/6yXXyOF.png)
Franco