Capacitors in Mesa Boogie Dual Rectifier

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Capacitors in Mesa Boogie Dual Rectifier

Postby Ricotjuh » 12 Jan 2019, 23:54

Hey,

In a Dual Rectifier, 1uF capacitors are connected to the cathode. Via an LDR or resistor to GND.
But when I look at the PCB these are not ordinary electrolyte capacitors, but yellow capacitors that look very similar to the construction of a resistor. The + side seems to be a bit tapered. See image below. Picture is not from the DR, but from another Mesa. But it only concerns the type of capacitor.
Someone any idea what type of capacitor this is, and what the advantage is, compared to an electrolyte capacitor.

Image
Last edited by Ricotjuh on 13 Jan 2019, 00:22, edited 1 time in total.
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Re: Capacitors in Mesa Boogie Dual Rectifier

Postby temol » 13 Jan 2019, 00:05

Looks like tantalum axial capacitor.

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Re: Capacitors in Mesa Boogie Dual Rectifier

Postby Ricotjuh » 13 Jan 2019, 00:36

You mean something like this?:
https://goo.gl/images/YqVVNf
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Re: Capacitors in Mesa Boogie Dual Rectifier

Postby temol » 13 Jan 2019, 09:39

Exactly. Check this - 1u tantalum axial cap.

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Re: Capacitors in Mesa Boogie Dual Rectifier

Postby Ricotjuh » 13 Jan 2019, 09:45

Completely clear. Thanks for the quick response
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Re: Capacitors in Mesa Boogie Dual Rectifier

Postby Optical » 14 Jan 2019, 02:28

Yeah Kemet tantalums
They last for a long time vs electrolydics, dirt cheap, fail obviously and are generally more compact - reasons why Mesa uses them.
They also fail shorted (an obvious giveaway vs a slowly wearing out electro cap) but seem to work well and last for a long time in Mesa amps regardless
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Re: Capacitors in Mesa Boogie Dual Rectifier

Postby Rocket Roll » 15 Jan 2019, 15:29

Actually, they have a higher failure rate than electrolytics, all of the data suggests.

One of the possible reasons for using them is distortion. When placed on signal path, they tend to introduce non-linearities, the sonic signature of which is very much respected in both pro-audio (Rupert Neve) and guitar-based audio (Tube Screamer, Rat).
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Re: Capacitors in Mesa Boogie Dual Rectifier

Postby Ricotjuh » 07 Jun 2019, 14:00

Now I have the following question. In the power amp section of the amplifier there is a 100nF capacitor (C51) in the feedback loop. But I think this is an MLCC capacitor. Anyone have any idea why no Orange Drop type capacitor is used here like in the rest of the amplifier? This also happens with C52. This is also a 100nF capacitor.
Image
Image
These are the two capacitors at the very top. Just below the resistor of the middle tube.
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Re: Capacitors in Mesa Boogie Dual Rectifier

Postby plush » 07 Jun 2019, 21:02

Ricotjuh wrote:Now I have the following question. In the power amp section of the amplifier there is a 100nF capacitor (C51) in the feedback loop. But I think this is an MLCC capacitor.


It can also be XY cap for safety reasons.
Or because the board lacks space.
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Re: Capacitors in Mesa Boogie Dual Rectifier

Postby alexradium » 09 Jun 2019, 07:50

Ricotjuh wrote:Now I have the following question. In the power amp section of the amplifier there is a 100nF capacitor (C51) in the feedback loop. But I think this is an MLCC capacitor. Anyone have any idea why no Orange Drop type capacitor is used here like in the rest of the amplifier? This also happens with C52. This is also a 100nF capacitor.
[ Image ]
[ Image ]
These are the two capacitors at the very top. Just below the resistor of the middle tube.
you don't need a HV capacitor there,there is probabli 10/15Vdc on one side.
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Re: Capacitors in Mesa Boogie Dual Rectifier

Postby Ricotjuh » 09 Jun 2019, 09:07

Okay, but what type of capacitor is normally applied at this position?
I assume that Mesa deliberately chose this type ?!
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