Not actually i already have dc protection board. I switch between my speakers and I worry about accidentally touch/short the output speaker cables of my amplifier.
Then it would be best to use connectors that don't have their contacts exposed, so you cannot accidentally short them. I learned this the hard way.
Recommended practice is to switch the power amplifier off when changing any cables, input or speaker. You may also consider building a speaker switching box. You could even have remote control and be able to switch from your listening chair.
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Thanks. I guess i will follow Fab suggestion use test points and try to make a sensing circuit.
Mr. Fabian;
I can not find any good 2k resistor %1 and non inductive.
What about using single resistor, it "MP930-1.00K-1%" replacement of R23/24 and R25/26 couples.
Its non inductive but probably could have more current noise than wirewounds due to thick film structure.
the best option is probably MRA-121K000FE12 but it is out of stock and very expensive.
Mr. Fabian;
I can not find any good 2k resistor %1 and non inductive.
What about using single resistor, it "MP930-1.00K-1%" replacement of R23/24 and R25/26 couples.
Its non inductive but probably could have more current noise than wirewounds due to thick film structure.
the best option is probably MRA-121K000FE12 but it is out of stock and very expensive.
Hi potstip
The Caddock MP930 is a good part and the part used for the FSSA amplifier for its high power dissipation with an heatsink. Without heatsink it is rated 2,25W. This is less than 3W+3W parts used in the USSA5 bom. However, the power rating specified is over designed like I prefer. If you use 4 x MP930 (2K) total then there is a lot of margin to prevent small change of value due to temperature drift under max signal amplitude. Using 2 x MP930 is also acceptable and if you install a small to-220 heatsink it is even better. But the problem you would encounter is to physically secure the installation of these to-220 type resistors on the pcb....
Fab
The Caddock MP930 is a good part and the part used for the FSSA amplifier for its high power dissipation with an heatsink. Without heatsink it is rated 2,25W. This is less than 3W+3W parts used in the USSA5 bom. However, the power rating specified is over designed like I prefer. If you use 4 x MP930 (2K) total then there is a lot of margin to prevent small change of value due to temperature drift under max signal amplitude. Using 2 x MP930 is also acceptable and if you install a small to-220 heatsink it is even better. But the problem you would encounter is to physically secure the installation of these to-220 type resistors on the pcb....
Fab
The following two resistors are non-inductive
Mills Resistor 2K Ohm 5W MRA-5 Series
Ohmite Resistor 2K0 Ohm 5W AG5 Series
Thanks
Do
Mills Resistor 2K Ohm 5W MRA-5 Series
Ohmite Resistor 2K0 Ohm 5W AG5 Series
Thanks
Do
Sorry, can't post my search. I just did a simple Google search for TPs and Digikey.
Cheers,
Greg
Cheers,
Greg
I bought them on amazon, they’re Uxcell parts:
Amazon.com: uxcell 200Pcs Black Gold Tone Soldering PCB Board Breadboard Test Point Pin: Home Improvement
Hi AnthonyA
No match required, they are used as current sources and there are pots for current adjustment.
Fab
No match required, they are used as current sources and there are pots for current adjustment.
Fab
@Anand: those were already on my radar, but thank you for your heads-up.
@Greg: the Uxcell parts were the ones I was asking about. After a google search I found them for sale on Ebay and Aliexpress for a substantially lower price than on Amazon. Do you know if they are made of brass?
Thanks guys.
@Greg: the Uxcell parts were the ones I was asking about. After a google search I found them for sale on Ebay and Aliexpress for a substantially lower price than on Amazon. Do you know if they are made of brass?
Thanks guys.
I do not know what they are made of. FWIW, they work and fit well. Hopefully, you just use them once.....😉
Is 5A at 26.4watts sufficient?
I know this might be bonkers, but I'm actually thinking of using Ian Canadas LifePO4 to power USSA. The LifePO4 modules are actually capable of 10's of amps instantaneous, however the relays are maximum of 8A - so 5A is comfortable and anything over 8A should be expected to damage the relays.
So, is this idea at all sensible? Battery powered USSA!
I know this might be bonkers, but I'm actually thinking of using Ian Canadas LifePO4 to power USSA. The LifePO4 modules are actually capable of 10's of amps instantaneous, however the relays are maximum of 8A - so 5A is comfortable and anything over 8A should be expected to damage the relays.
So, is this idea at all sensible? Battery powered USSA!
It's not bonkers, no more than my idea of powering a low wattage class A design with a FW tube rectifier.
The problem that I see is dealing with the tremendous heat dissipation in the chassis. This type of battery chemistry is very stable and you will get a lot of cycles out them, but heat is not their friend.
Using really soft sounding hexfreds in a standard CRC type supply might be a better choice than the LifePo.
It would certainly benefit and probably yield a different sound to the amp for sure. However, the noise floor could end up being higher.
I think the LiFePo is more appropriate for linestage supplies. Again, because of heat. So, if you do this, I would locate them in another chassis.
Just my .02c (in your case, my 2p)
Cheers,
Greg
The problem that I see is dealing with the tremendous heat dissipation in the chassis. This type of battery chemistry is very stable and you will get a lot of cycles out them, but heat is not their friend.
Using really soft sounding hexfreds in a standard CRC type supply might be a better choice than the LifePo.
It would certainly benefit and probably yield a different sound to the amp for sure. However, the noise floor could end up being higher.
I think the LiFePo is more appropriate for linestage supplies. Again, because of heat. So, if you do this, I would locate them in another chassis.
Just my .02c (in your case, my 2p)
Cheers,
Greg
Thanks - yes LifePO4 would definately have to be thermally separated.
I think I'm likely to go with XRK's SLB power supply if the LifePo4 route doesn't bare out.
Any other suggestions for cheap / low noise power?
I think I'm likely to go with XRK's SLB power supply if the LifePo4 route doesn't bare out.
Any other suggestions for cheap / low noise power?