Best choices for 220µF capacitors
Hi!
There is a lot of options for the 220µF capacitors.
Beside the 12.5mm max width, and max voltage 50/63 or 100V (depending on you PSU, mine is 47V DC),
what would you suggest ?
Lowest ESR ? Ripple current ? balanced (medium ESR, medium ripple?)
"Audio grade" if that's meaning anything?
Panasonics? Nichicons? Any brand ?
Thanks for your suggestion
JMK
Hi!
There is a lot of options for the 220µF capacitors.
Beside the 12.5mm max width, and max voltage 50/63 or 100V (depending on you PSU, mine is 47V DC),
what would you suggest ?
Lowest ESR ? Ripple current ? balanced (medium ESR, medium ripple?)
"Audio grade" if that's meaning anything?
Panasonics? Nichicons? Any brand ?
Thanks for your suggestion
JMK
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Each capacitor will have some "fingerprint" on sound, so the choice goes towards personal taste. My personal favourite is Nichicon FG (or FW) for demanding positions and Panasonic FC for the others. The latest is very neutral capacitor, while in some configurations might lack some instrument body.
For 47V rails you can use 63V rated 220uF Panasonic FC in the rails. I always use and supply in kits the Panasonic FCs and they perform very well. If you want to use "audio grade" capacitors then use them for the 2200uF ones. I use and recommend Panasonic FM here. These are nice, very nice caps.
Ground cnx for Peeceebee setup
Hi Shaan !!
I'm into reading carefully your detailed setup doc.
In section 2 - pagraph c., you write:
Make sure the heatsink is connected to the the power supply 0V ground. Without this .....
This is unclear to me : my 0V is nowhere connected to the chassis/earth.
I don't want to have my OV connected to any heatsink or chassis.
SMPS PSU (OV not connected to chassis) in dual mono setup, preamp also isolated etc
Is it OK to connect the 0V to the chassis through a 100 ohm resistor (how big ? 1/4W?)
Thanks
JMK
Hi Shaan !!
I'm into reading carefully your detailed setup doc.
In section 2 - pagraph c., you write:
Make sure the heatsink is connected to the the power supply 0V ground. Without this .....
This is unclear to me : my 0V is nowhere connected to the chassis/earth.
I don't want to have my OV connected to any heatsink or chassis.
SMPS PSU (OV not connected to chassis) in dual mono setup, preamp also isolated etc
Is it OK to connect the 0V to the chassis through a 100 ohm resistor (how big ? 1/4W?)
Thanks
JMK
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Ajit - 2 STEREO MODULES - PAID
steefdebruijn - 2 PCBS - PAID
amitskamal - 1 STEREO KIT - PAID
Neurotica - 2 PCBs - PAID
vvs07 - 4 PCBs - PAID
outtek - 2 PCB + 4 PAIR MOSFET - PAID
ejno - 2 PCBS - PAID
craydive - 4 PCBS - PAID
PinkPink - 4 PCBs - PAID
J.M.K - 4 PCBS + 2 PAIR MOSFET - PAID
CitizenKane - 4 PCBs - PAID
gaborbela - 2 PCBs - PAID
Kheon - 2 PCB's - PAID
Oracle1 - 2 PCBs + 4 PAIR MOSFET
The Prof - 1 STEREO KIT - INVOICE SENT
hallcon83 - 4 PCBs - INVOICE SENT
smouse - 2 PCBS - PM SENT
Boards will be ordered on Monday. I will receive the batch by August 20. Shipping will commence afterwards. Shipping invoice will be sent by mid-August to members from abroad.
If there is a mistake in the list then please let me know.
Thanks.
p.s. as usual, MOSFETs are already home. 30 more pairs coming next week.
Attachments
Hi JMK.
In a metal cabinet, without the ground connected to the heatsink via the chassis the amplifier may become unstable and oscillate, making all kind of problems starting with usually burnt zobel resistors. As this is a fast amplifier, it is prone to think of any capacitively coupled and electrically floating metal piece connected to its output (via the back of the MOSFETs) as an antenna and run into local RF positive feedback loop, causing the oscillation. Connecting the metal to ground will shunt the antenna effect and the amplifier will run properly.
You can use 100ohm but 10ohm/1Watt is more common, along with a pair of 10A rated diodes in antiparallel configuration and a 0.1uF film capacitor. This is a typical ground-loop breaker module. The setup guide deals with individual channels installed on standalone heatsinks, so the Gound is suggested to be connected directly to the heatsink body without any resistor. In a chassis assembly, a loop breaker is used.
OK, then if I understand you right, as my heatsinks are parts of the steel chassis,
the heatsinks are already to ground. No need to have the O volts to ground.
The back of my mosfets will be isolated with mica pads.
There can't be any loop in my setup.
Some setups have OV to ground, some don't have it.
Thank you.
JMK
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The Ground I mentioned is the PSU's 0V, not mains earth ground. Are you sure the PSU ground is already connected to the chassis?
In my chassis, the PSUs's (2 PSUs) OV are not connected to chassis nor earth.
The PSUs's grounds are of course to earth (Cresnet SMPS).
And ground output to speakers also not to earth/chassis.
What is confusing is using the word "ground" and not mentioning if it's connected to chassis or not, given that the chassis has to be connected to earth via the main AC plug.
JMK
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Ok. I understand.
I will try to state it as clearly as I can.
>The PSU 0V needs to be connected to the chassis in order to prevent oscillation in this amplifier<.
But of course during assembly if you see no need to connect it to chassis (or in case it is already connected through the SMPSs) then don't.
Cheers!
shaan
I will try to state it as clearly as I can.
>The PSU 0V needs to be connected to the chassis in order to prevent oscillation in this amplifier<.
But of course during assembly if you see no need to connect it to chassis (or in case it is already connected through the SMPSs) then don't.
Cheers!
shaan
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Ok. I understand.
I will try to state it as clearly as I can.
>The PSU 0V needs to be connected to the chassis in order to prevent oscillation in this amplifier<.
But of course during assembly if you see no need to connect it to chassis (or in case it is already connected through the SMPSs) then don't.
Cheers!
shaan
Hi Shaan,
If I make a double mono, in one case, is it ok to wire the ground (0V) of the to PSU to the heatsinks, so the will be linked together by the cabinet ?
Do I need to wire the earth to the cab too ?
Thanks,
Fabio
ground ground
IF your heatsinks are parts of the chassis (and chassis linked to earth as it should), there is no need to do this (provided they're properly isolated from the amplifiers' modules).
If your heatsinks are not parts of the chassis, link them to it, and be sure the heatsinks are properly isolated from the modules.
This is what I always did for my dual monos, and check the input and output plugs that have to be also carefully isolated. Otherwise you'll have various loops .......
And check that your preamp's channels are also isolated !
JMK
IF your heatsinks are parts of the chassis (and chassis linked to earth as it should), there is no need to do this (provided they're properly isolated from the amplifiers' modules).
If your heatsinks are not parts of the chassis, link them to it, and be sure the heatsinks are properly isolated from the modules.
This is what I always did for my dual monos, and check the input and output plugs that have to be also carefully isolated. Otherwise you'll have various loops .......
And check that your preamp's channels are also isolated !
JMK
Hi Fabio.
Having the PSU 0V connected to all floating metal parts in and around an amplifier is more important than having the earth from mains plug being connected to chassis. This is not from a personnel safety standpoint, but amplifier stability standpoint.
If the heatsink metal is electrically connected to the metal of the chassis then it is ok to make one connection from PSU 0V to the chassis through a ground loop breaker.
Hi JMK.
As you mentioned previously, your SMPSs' 0V is already connected to mains earth. This means the 0V is also directly connected to your chassis because the mains earth is connected to chassis via the SMPS.
Most linear PSUs accept a stepped-down voltage trom transformer secondary and do not have an on-board terminal for connecting the mains-earth, unlike most SMPSs that are not double-insulated and are used in amplifeirs. Because of this, 1) the linear PSU's 0V needs a manual connection to the chassis to keep all metal at 0V potential for amplifier stability, usually through a loop breaker, and 2) the mains earth is bolted directly to chassis metal, for personnel safety during a primary-secondary short. This is exactly like your setup with SMPSs, except there is a loop breaker involved.
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If there is DC present at the output of the preamplifier then yes, a capacitor will be good. 10uF will be sufficient for adequate LF-response.