Amazon, eBay, Mouser, DigiKey, Arrow... a web search for the barrel size you'd like to use (you didn't mention the size for your PSU) should produce plenty of results. Solder your own wire of choice, or many come with wires pre-soldered.
Here's an example of a search I used for a 3.5 mm female chassis mount barrel connector. Adjust accordingly for the size of the connection on your PSU. Ensure that you know if your PSU barrel uses a positive center or negative center prior to wiring the female for your amp. Again, assuming male from PSU.
3.5mm female barrel connector chassis mount - Google Search
Here's an example of a search I used for a 3.5 mm female chassis mount barrel connector. Adjust accordingly for the size of the connection on your PSU. Ensure that you know if your PSU barrel uses a positive center or negative center prior to wiring the female for your amp. Again, assuming male from PSU.
3.5mm female barrel connector chassis mount - Google Search
Question on twisted pair from RCAs to board
Hello-
I am nearly finishing the first of two amps, and as I try to figure out how to fix the LEDs in place, I notice that I did not twist the grey/white and grey/red pairs from the RCAs to the board. I'd like to avoid- especially- reworking the RCAs, but I can probably put a few twists in by de-soldering the wires at the board.
I am doing the 1.8, and at a certain point I just went with the 1.8 wiring diagram.
I have a basic understanding of the theoretical importance of twisting low signal wires, but how important is this, here?
Thanks, Clay
Hello-
I am nearly finishing the first of two amps, and as I try to figure out how to fix the LEDs in place, I notice that I did not twist the grey/white and grey/red pairs from the RCAs to the board. I'd like to avoid- especially- reworking the RCAs, but I can probably put a few twists in by de-soldering the wires at the board.
I am doing the 1.8, and at a certain point I just went with the 1.8 wiring diagram.
I have a basic understanding of the theoretical importance of twisting low signal wires, but how important is this, here?
Thanks, Clay
Clay,
Do not worry about twisting the input pairs. Just keep each pair close to each other along their length. (Tape or ty-wrap them?)
For the LEDs see the suggestions in step 44 of the build guide. Amp Camp Amp V1.6 Build Guide - diyAudio Guides
Or 'build up' their thickness with tape again?
Do not worry about twisting the input pairs. Just keep each pair close to each other along their length. (Tape or ty-wrap them?)
For the LEDs see the suggestions in step 44 of the build guide. Amp Camp Amp V1.6 Build Guide - diyAudio Guides
Or 'build up' their thickness with tape again?
This could be a number of things, but you will need to narrow the options down before we can help. First, is the noise happening with no inputs connected or just when you short the inputs together? Could be your preamp/input source if you get the hum there. If not, try a different power supply as it could be that too - the quality and design of SMPSs varies wildly in my experience if that is what you are using. Next, measure resistance between the RCA/Balanced inputs and the chassis and the same with the speaker posts - are they isolated from the chassis? Try to narrow things down to either the input sources, power supply or the amp and we can try to help your debug there.
Also as @6L6 always reminds people, post clear pictures of your build/setup.
--Tom
Also as @6L6 always reminds people, post clear pictures of your build/setup.
--Tom
This could be a number of things, but you will need to narrow the options down before we can help. First, is the noise happening with no inputs connected or just when you short the inputs together? Could be your preamp/input source if you get the hum there. If not, try a different power supply as it could be that too - the quality and design of SMPSs varies wildly in my experience if that is what you are using. Next, measure resistance between the RCA/Balanced inputs and the chassis and the same with the speaker posts - are they isolated from the chassis? Try to narrow things down to either the input sources, power supply or the amp and we can try to help your debug there.
Also as @6L6 always reminds people, post clear pictures of your build/setup.
--Tom
It's the input rca, when it's inserted, it has the noise. It is normal to have this kind of idle noise?
is it supposed to be dead silent? im not sure about this. however, once it get real hot, it start to be much better
1 more thing is that i have adjusted the dc offset using 24 SMPS meanwell , from 10.+ to exactly 12 V , somehow it sounded lack of power compare to 10V+ (heatsink is hot) to 12V ( heat sink is normal, able for 5 sec touching)
may i know what is dc offset when comes to this? increasing would be good or decreasing ？ or is it dont affect sound or watt anyway ?
1 more thing is that i have adjusted the dc offset using 24 SMPS meanwell , from 10.+ to exactly 12 V , somehow it sounded lack of power compare to 10V+ (heatsink is hot) to 12V ( heat sink is normal, able for 5 sec touching)
may i know what is dc offset when comes to this? increasing would be good or decreasing ？ or is it dont affect sound or watt anyway ?
in the quiet of your room, while seated at your listening chair, you should not hear anything when music is not playing....there are factors to consider, for example, is your air conditioning adding to ambient noise?
i have not encountered an amp that is dead quiet unless you stick your ears close the the tweeters....
DC offset isn't really the best term to use, it is a DC bias point you set and setting it to half the supply voltage (so 12 volts on a 24 volt supply) means the amplifier can deliver maximum voltage swing above and below this point. In other words it will clip symmetrically.
It has no effect on total heat generated, only the heat distribution per device.
It has no effect on total heat generated, only the heat distribution per device.
thanks for the information. then what about the premium parts, tungsten mod suggesting 12.4 V, and sound quality is slightly improved. what actually is changing inside this ?
You should have a silent amplifier at idle, so any notable noise/hum is not expected. An amp with no inputs connected, but outputs connected, should have next to no noticeable noise on the speakers or something is not setup correctly. If you experience noise/hum *after* you connect something to the input, its likely that device is the reason for the loop.
Since you mentioned it only happens when you connect to the input on the RCA, have you tried a different input source? I've had ground loops in the past because of misbehaving input devices and their interaction with the amp.
The way I've tracked these down in the past is to get the old DVM Meter out and start measuring for continuity points and looking for unexpected voltages on the grounds indicating currents flowing and loops. As a general rule, the circuit's return should have continuity to earth/chassis ground at a single "star ground" point point and otherwise isolated from that point. That start point is only connected to chassis ground the 3-type isolator (diode bridge, resistor and cap). Take a look at this really well put together article on this topic for some other ideas that also explains why this is important:
Audio Component Grounding and Interconnection - diyAudio
For your ACA, check to ensure you haven't accidentally connected the negatives somewhere to the chassis. I did this accidentally on my very first build where I bent the negative on the RCAs too far and it touched the chassis in a tiny place. The DVM will catch these cases %100 the time - just listen for the beep as you probe around!
--Tom
That is close enough; you don't need to be perfectly on 24VDC. I've actually built a linear that delivers a little more than 24VDC and its fine too. Ensure that you are biasing to less than or equal to half the actual rail voltage (not simply 24v) and you should be pretty spot on.
--Tom