I did it the hard way cause I was cheap... in the end, the time spent... maybe I should have bought it too 
The bottom plate is 1/4" aluminum plate with slots cut into them for the venting as you see from the previous pic. The front and back plate as you see are 1/8" aluminum plate, and the heat sinks are from Antek. The feet are 2" Al rounds, the top is 1/8" perforated Al.
The hard part was drilling and tapping screw holes into the 1/4" bottom plate for the front and back plate. I don't like the look of angle irons so I did it the hard way
Oh I still have a front plate to add on, therefore the 4 holes, but I'm still tweaking.
So far it runs about 46C on the heatsinks.
The bottom plate is 1/4" aluminum plate with slots cut into them for the venting as you see from the previous pic. The front and back plate as you see are 1/8" aluminum plate, and the heat sinks are from Antek. The feet are 2" Al rounds, the top is 1/8" perforated Al.
The hard part was drilling and tapping screw holes into the 1/4" bottom plate for the front and back plate. I don't like the look of angle irons so I did it the hard way
Oh I still have a front plate to add on, therefore the 4 holes, but I'm still tweaking.
So far it runs about 46C on the heatsinks.
Last edited:
sorry i just have to comment here, can someone please explain how connecting an rca shield at one end does anything at all, since the shield and ground are directly connected together with rca? it makes no sense at all to me. lifting the shield can be helpful to sort out grounding errors with xlr until you sort it out the right way, as the ground wire and shield are not connected, but with rca it doesnt make any difference. ground and shield are the same thing, the noise will travel back towards the source where you connected it along with ground and then all the way back again along the ground wire, if you must describe it in linear terms at least.
even if you create a much lower impedance path to ground at the source from the rca by using a thicker gauge wire to connect ground than what is used in the cable signal ground, some current will still flow, but if its the same gauge, or thinner, little or none will flow to ground in the source at all.
even if you create a much lower impedance path to ground at the source from the rca by using a thicker gauge wire to connect ground than what is used in the cable signal ground, some current will still flow, but if its the same gauge, or thinner, little or none will flow to ground in the source at all.
Last edited:
Hi,
the Source connects to the receiver with a "Flow & Return".
A stereo Source will have two Flows and one or two Returns.
These Signal Flow and Signal Return must go into the Receiver.
The input stage of the Receiver measures the voltage between the Flow and Return while audio Signal current is flowing around the circuit.
The Problem comes from implementing a schematic literally, where all the different "Returns" are connected together and label GND.
You are required to think about the current flows in each circuit and arrange that the returns are connected ONLY where and if required.
The Signal Return should not be connected to the Power Ground.
This allows the input flow and return to be completed as a circuit for the audio Signal Current to flow around. No need to break returns to avoid loops. The shield can be attached at both ends.
Now connect the Signal Return (Ground) to the Power Ground. A loop !
Break the shield.
Now analyse the route that the audio signal current must flow to return to it's source.
Never connect the Signal Return to the Power Ground to allow a length of trace/wire to share a part route carrying different currents.
the Source connects to the receiver with a "Flow & Return".
A stereo Source will have two Flows and one or two Returns.
These Signal Flow and Signal Return must go into the Receiver.
The input stage of the Receiver measures the voltage between the Flow and Return while audio Signal current is flowing around the circuit.
The Problem comes from implementing a schematic literally, where all the different "Returns" are connected together and label GND.
You are required to think about the current flows in each circuit and arrange that the returns are connected ONLY where and if required.
The Signal Return should not be connected to the Power Ground.
This allows the input flow and return to be completed as a circuit for the audio Signal Current to flow around. No need to break returns to avoid loops. The shield can be attached at both ends.
Now connect the Signal Return (Ground) to the Power Ground. A loop !
Break the shield.
Now analyse the route that the audio signal current must flow to return to it's source.
Never connect the Signal Return to the Power Ground to allow a length of trace/wire to share a part route carrying different currents.
Yes. It seems to me I currently do not have a loop and that connecting the signal return to the power gnd and then removing the power gnd attachment from the board is sort of the same thing. Simpler path to the star but I do not know if that matters. I still don't see a loop but I could be missing it.
Hi qusp
Sorry but I am not shure I understand
RCA PHONO plugs most times is just one cable and a screen.
As I understand and may be totaly wrong
On Balanced Shield there is just as an extra vire a twisted pair will do the job
this is because the balanced circuit amplify the differential signal (same voltages with phase at 180 degrees) and as the noise is comon (same polarity same phase) it get deleted Comon Mode rejection
With RCA the one I have have 1 cable inside the screen (are those the cheap and nasty ones?)
Ground loops
Now your preamplifier is connected to the ground with the safety earth on the mains plug. (do no mess with it)
Your amplifier have also a grond connected to earth with the mains plug (do not mess with it even more)
There would be a small difference in potential between the 2 caused by small difference in the earth cables.
You do not want noise to get in to the cable so you put a screen on the cable and connect at the preamplifier end the noise can not go in to the preamplifier and get amplified as that is an output.
Now you cant stop the noise getting in the screen of the cable
Connect the screen at the amplifier end there would be a small difference in potential between your Preamplifier and Amplifier and a small difference at the different conection point the small stuff does not get rejected (Comon Mode Rejection) as in the balanced circuit.
It get amplified.
Now if you have exactley the same resistance between the different point in to wich the Ground is connected the different point will be exactley at the same potential. But you can't have exactley the same potential as (bit extreme) 1 mm extra lengt of cable will ad 1mm extra of cable resistance and cause a small difference in potential.
This small difference get amplified you got a ground loop.
Ad the screen conection to the other chanell on the amplifier now you have 3 cables that should be at the same potential but they can not be as maybe you have 1 extra mm of lenght on the second screen so more difference get amplified.
On the F5 you got 15dB gain so no big deal bit of noise but not much but it is there truble is at times this will go around in circles and each time it get amplified a bit more.
Use just one conection for part of the circuit that should be at the same potential and you cut the loop.
One thing to keep in mind the Earth cable is there for safety and it shuld be never cut or messed about with
Sorry but I am not shure I understand
RCA PHONO plugs most times is just one cable and a screen.
As I understand and may be totaly wrong
On Balanced Shield there is just as an extra vire a twisted pair will do the job
this is because the balanced circuit amplify the differential signal (same voltages with phase at 180 degrees) and as the noise is comon (same polarity same phase) it get deleted Comon Mode rejection
With RCA the one I have have 1 cable inside the screen (are those the cheap and nasty ones?)
Ground loops
Now your preamplifier is connected to the ground with the safety earth on the mains plug. (do no mess with it)
Your amplifier have also a grond connected to earth with the mains plug (do not mess with it even more)
There would be a small difference in potential between the 2 caused by small difference in the earth cables.
You do not want noise to get in to the cable so you put a screen on the cable and connect at the preamplifier end the noise can not go in to the preamplifier and get amplified as that is an output.
Now you cant stop the noise getting in the screen of the cable
Connect the screen at the amplifier end there would be a small difference in potential between your Preamplifier and Amplifier and a small difference at the different conection point the small stuff does not get rejected (Comon Mode Rejection) as in the balanced circuit.
It get amplified.
Now if you have exactley the same resistance between the different point in to wich the Ground is connected the different point will be exactley at the same potential. But you can't have exactley the same potential as (bit extreme) 1 mm extra lengt of cable will ad 1mm extra of cable resistance and cause a small difference in potential.
This small difference get amplified you got a ground loop.
Ad the screen conection to the other chanell on the amplifier now you have 3 cables that should be at the same potential but they can not be as maybe you have 1 extra mm of lenght on the second screen so more difference get amplified.
On the F5 you got 15dB gain so no big deal bit of noise but not much but it is there truble is at times this will go around in circles and each time it get amplified a bit more.
Use just one conection for part of the circuit that should be at the same potential and you cut the loop.
One thing to keep in mind the Earth cable is there for safety and it shuld be never cut or messed about with
Progress report
Same bias setting as yesterday 4 hours run
46.4 C at spreader
offset steady at 2 mV
Twin mosfets at 4 A rail 25 V or such
beat the cra... out of an old speaker today
1) 20 V out scope set at 1 V division probe at X10
2) 22 V and clipping but have a look at 6 it sounds great
3) 20 V 5V division probe at X1
4 and 5 )100 KHz square baad but then have a look at the botom that is the output of the generator (need to work same more overtime and get a better one)
6) Plaiing same music Yolanda be cool We no speack Americano again 5 Vdivision
was going to post Gold and Brown but not shure about the Brown part
I got it set up to play MP3 files out of the PC troug an Akai SS1
I need a preamplifier but can't get the bits for it (HINT!)
6) triing to get the PC to take same mesuraments.
I got a decent sound card M delta Audiophile 192
but not realy ready to post pictures of it
THD 0.014 THD and Noise 0.038 tried with (gogolit but do not pay for it jet)
True RTA and ARTA.
ARTA seems much beter IMO
tried same beter squares out of those 2 programs but not shure what is hapening there I will have to read the manuals + the SS1 (I remember seeing the glossy pictures of those when I was 14 ) is on the signal chain so preaty shure the THD figures are wrong.
So tanks to Papa for one more most enjoable day is on order.
PS was worring a while ago about speaker protection the amp and the speaker had a year worth of bubus done to them today and no problems there
Silence with no signall or disconected cables is realy good
No tumps on speakers at start up and power down
Same bias setting as yesterday 4 hours run
46.4 C at spreader
offset steady at 2 mV
Twin mosfets at 4 A rail 25 V or such
beat the cra... out of an old speaker today
1) 20 V out scope set at 1 V division probe at X10
2) 22 V and clipping but have a look at 6 it sounds great
3) 20 V 5V division probe at X1
4 and 5 )100 KHz square baad but then have a look at the botom that is the output of the generator (need to work same more overtime and get a better one)
6) Plaiing same music
Yolanda be cool We no speack Americano again 5 Vdivision was going to post Gold and Brown but not shure about the Brown part
I got it set up to play MP3 files out of the PC troug an Akai SS1
I need a preamplifier but can't get the bits for it (HINT!)
6) triing to get the PC to take same mesuraments.
I got a decent sound card M delta Audiophile 192
but not realy ready to post pictures of it
THD 0.014 THD and Noise 0.038 tried with (gogolit but do not pay for it jet)
True RTA and ARTA.
ARTA seems much beter IMO
tried same beter squares out of those 2 programs but not shure what is hapening there I will have to read the manuals + the SS1 (I remember seeing the glossy pictures of those when I was 14 ) is on the signal chain so preaty shure the THD figures are wrong.
So tanks to Papa for one more most enjoable day is on order.
PS was worring a while ago about speaker protection the amp and the speaker had a year worth of bubus done to them today and no problems there
Silence with no signall or disconected cables is realy good
No tumps on speakers at start up and power down
Tanks dazed2
Yes it there steady at +- 2 mV at start up is about 25 mV
this is just with the one chanel and the case open.
I will keep an eye on it
Once I have a chance to get the ther ready and close the case it will be a different story but case is just a very light aluminium frame and sides and top are made with a sandwich of wire mesh and wood. (pictures posted earlier on this tread)
At this stage I am not using the current limiters.
I will be triing different combinations like Papa and Erno cascode
Toshibas Farchild and IRF
I am running 2 A on each of the 4 mosfets and so far is prety cool will have to wait and see as I would like to try the balanced version as well (the extra screws on the heath spreaders) but sems like is not a god idea with 4 homs speakers (not that I have realy understod why so far).
Yes it there steady at +- 2 mV at start up is about 25 mV
this is just with the one chanel and the case open.
I will keep an eye on it
Once I have a chance to get the ther ready and close the case it will be a different story but case is just a very light aluminium frame and sides and top are made with a sandwich of wire mesh and wood. (pictures posted earlier on this tread)
At this stage I am not using the current limiters.
I will be triing different combinations like Papa and Erno cascode
Toshibas Farchild and IRF
I am running 2 A on each of the 4 mosfets and so far is prety cool will have to wait and see as I would like to try the balanced version as well (the extra screws on the heath spreaders) but sems like is not a god idea with 4 homs speakers (not that I have realy understod why so far).
Parts Check
Ok guys, getting ready to make a parts order for my f5 PSU (using Cviller boards, thank you christian) and am posting for a quick double check before buying.
CAPS = PANASONIC|ECOS1VP333EA|CAPACITOR, 33000UF, 35V | element14 Australia
2K2 = VISHAY DALE|CW02B2K200JE73|RESISTOR WIREWOUND, 2.2KOHM, 3W | element14 Australia
.47 = VISHAY DALE|CW02BR4700JE12|RESISTOR WIREWOUND, 0.47OHM, 3W | element14 Australia
REC = VISHAY FORMERLY I.R.|VS-GBPC3502A|BRIDGE RECTIFIER, 35A, 200V | element14 Australia
My two concerns are:
1: Are 5% resistors OK??
2: Why can i get this bridge rec for $7 or one with similar specs for $25, will the cheapy work for the f5 or?
Cheers for any advice
Dean
Ok guys, getting ready to make a parts order for my f5 PSU (using Cviller boards, thank you christian) and am posting for a quick double check before buying.
CAPS = PANASONIC|ECOS1VP333EA|CAPACITOR, 33000UF, 35V | element14 Australia
2K2 = VISHAY DALE|CW02B2K200JE73|RESISTOR WIREWOUND, 2.2KOHM, 3W | element14 Australia
.47 = VISHAY DALE|CW02BR4700JE12|RESISTOR WIREWOUND, 0.47OHM, 3W | element14 Australia
REC = VISHAY FORMERLY I.R.|VS-GBPC3502A|BRIDGE RECTIFIER, 35A, 200V | element14 Australia
My two concerns are:
1: Are 5% resistors OK??
2: Why can i get this bridge rec for $7 or one with similar specs for $25, will the cheapy work for the f5 or?
Cheers for any advice
Dean