well pretty much done with mine.maybe a little cleanup and stuff. i do however get a buzz if i turn the pot over 75%.
Dear peter :
At post #31 you said that that Bare wire is okay, if it is not contact with other wires or chassis. But when i saw Post #44 you were using teflon wires to the binding post....
Can you explain it, why ???
At post #31 you said that that Bare wire is okay, if it is not contact with other wires or chassis. But when i saw Post #44 you were using teflon wires to the binding post....
Can you explain it, why ???
Because the bare wire I'm using is only 26ga and not suitable for output connection.
I usually use Kimber 19ga for speakers.
I usually use Kimber 19ga for speakers.
DC Offsets
Hi
I have built and tested 6 gainclones using the audiosector pcb's.
All 6 have hi dc offsets. lowest is 75mv, 80, 92, 94, 100 and highest is 120mv
These offsets are measured with no input or volume control and an 8ohm 20w resistor on the output. (same values are measured without the 8 ohm resistor on the output)
Pcb's are the same, the resistors are all measured so they are close to eachother. I am using the values recommended by the kit. all resistors are metalfilm 0.25w
I am using the same Power supply for all gainclones in the test.
trafo is 2x22 300VA the rectifier is also the one i got from audiosector wheere i got the gainclone pcb, they are populated with th Mur 860 diodes and 2 10uf caps.
Can anyone explain the offsets are so high? is over 100mv bad for the speakers.
I did after these tests put in a 10uf cap in series with the 680ohn resistor and the dc offset is now 1mv or close to zero.
Hi
I have built and tested 6 gainclones using the audiosector pcb's.
All 6 have hi dc offsets. lowest is 75mv, 80, 92, 94, 100 and highest is 120mv
These offsets are measured with no input or volume control and an 8ohm 20w resistor on the output. (same values are measured without the 8 ohm resistor on the output)
Pcb's are the same, the resistors are all measured so they are close to eachother. I am using the values recommended by the kit. all resistors are metalfilm 0.25w
I am using the same Power supply for all gainclones in the test.
trafo is 2x22 300VA the rectifier is also the one i got from audiosector wheere i got the gainclone pcb, they are populated with th Mur 860 diodes and 2 10uf caps.
Can anyone explain the offsets are so high? is over 100mv bad for the speakers.
I did after these tests put in a 10uf cap in series with the 680ohn resistor and the dc offset is now 1mv or close to zero.
That is quite normal, the offsets have been explained here: http://www.diyaudio.com/forums/audi...-kit-building-instructions-5.html#post1523699
Hello to everyone!
I have built my first gainclone (premium kit from audiosector) lately. It sounds great. Good work Peter!
But I have some serious problem with cellular phone signals interference.
I have followed the guide. Done power star grounding as suggested. My enclosure is all aluminum with 3mm back, 2mm top and bootom and 10mm side and front plates. And of course it is grounded to the same power star and iec power socket.
With all sealed and closed I'm not able to place my iphone closer then 4 meters from the amp. I have very loud and typical for phones distortions/noise otherwise.
I have placed 330pF polystyrene capacitor between 7th and 8th pin of the chip. Indeed that helped for occasional pops from all kind of power switching actions. I have a very reliable test for that with soldergun connected to the same power outlet as the amp. Before application of that 330pF capacitor switching off the soldergun produced loud pop. Now its gone.
The thing is, that did nothing to the cellular phone interference. Not a bit. What to do?
My speakers are dead silent with this amp. No humm, no buzz, nothing except phones. I have several bluetooth and wifi devices placed no more than a few centimeters from the amp. Nothing. But when I enter my room with the phone it is audible instatnly 🙁
I have built my first gainclone (premium kit from audiosector) lately. It sounds great. Good work Peter!
But I have some serious problem with cellular phone signals interference.
I have followed the guide. Done power star grounding as suggested. My enclosure is all aluminum with 3mm back, 2mm top and bootom and 10mm side and front plates. And of course it is grounded to the same power star and iec power socket.
With all sealed and closed I'm not able to place my iphone closer then 4 meters from the amp. I have very loud and typical for phones distortions/noise otherwise.
I have placed 330pF polystyrene capacitor between 7th and 8th pin of the chip. Indeed that helped for occasional pops from all kind of power switching actions. I have a very reliable test for that with soldergun connected to the same power outlet as the amp. Before application of that 330pF capacitor switching off the soldergun produced loud pop. Now its gone.
The thing is, that did nothing to the cellular phone interference. Not a bit. What to do?
My speakers are dead silent with this amp. No humm, no buzz, nothing except phones. I have several bluetooth and wifi devices placed no more than a few centimeters from the amp. Nothing. But when I enter my room with the phone it is audible instatnly 🙁
It is unusual as I often use the iphone for amp testing (the phone 20cm from the amp) and didn't observe any particular problems.
What speaker cables and interconnects are you using? Maybe they pick up interferences?
Could be also your local network, what happens if iphone is in Airplane Mode?
What speaker cables and interconnects are you using? Maybe they pick up interferences?
Could be also your local network, what happens if iphone is in Airplane Mode?
iPhone disturbance
Hi
I also have the same problem with the iPhone going in on the signal of the audiosector amp. I also have it sealed in a metal box but that doesn't help
My soultion is to shut off the phone or place it somewhere far away.🙂
This solves 2 things
1. I do not get interrupted while listining to music😀
2. The noise in the amp i s gone
Best regards
Edwin
Hi
I also have the same problem with the iPhone going in on the signal of the audiosector amp. I also have it sealed in a metal box but that doesn't help
My soultion is to shut off the phone or place it somewhere far away.🙂
This solves 2 things
1. I do not get interrupted while listining to music😀
2. The noise in the amp i s gone
Best regards
Edwin
I'm using all Zu's stuff: speakers: "Druids mkIV", interconect: "Varial", spk cables: "Libtec".
DAC: your NOS in a separate aluminum box. DAC tested with all EMI conditions and it is most probably not a source of the problem.
The interferences occur when there is some gsm radio activity of the phone. I used to force the iphone to talk to BTS by sending push notification to myself (or phoning myself with a second device). And that produces those loud distortions in speakers. Of course in Airplane mode gsm radio is shut down and wi-fi is not a problem as I said previously.
I was trying to isolate the source in (some could say) primitive way. I was changing the proximity of my iphone to the cables, speakers, amp's power transformer (i have separated it from the rest of the amp with a meter long cables) and the amp's pcb-s. Most definitely the sound was the loudest near the amps printed boards.
In the distance of 20 cm between the phone and the amp the distortions are in fact so loud that one can be afraid of the speakers. No way to put the phone and the amp on the same desk. And here are some observations:
- Distortions do not depend on the potentiometer and it's position (including 0 position).
- They do not depend on the source selected with the selector (including setting unconnected input or shorted to ground input)
- They do not depend on devices connected to the amp (DAC I mean), whether they are switched on or off, or not connected at all.
- They are louder in the right channel (I switched the speakers to put them out of equation) but present also in the left one.
- The sound does not depend on the distance between the power transformer and the amplifier, length of the power cord, wall power outlet position (I have three in my room)
- But of course it depends on the phone position in my room and on its relation to the amp. I think it has something to do with BTS location and the antenna beam forming but I'm not an expert by any means.
As I said I was trying to place a 300pF capacitor at the chips inputs. Later I put another pair betwen the (+) input and the ground, another pair between amp's (i mean rca) inputs and ground and between outputs. To no avail.
Now I'm scratching my head 🙁
Lucky you. I have to be online at all time and want(-ed I'm affraid) to use this amp all day.
Hi,
when I am near the amp (premium kit) and I have the Iphone in my pocket I also occasionally hear the typical buzz of cell phone interference but at low level and when I sit back on the armchair the buzz stops.
Renato
when I am near the amp (premium kit) and I have the Iphone in my pocket I also occasionally hear the typical buzz of cell phone interference but at low level and when I sit back on the armchair the buzz stops.
Renato
Forgive me for asking a question which is probably answered somewhere in the labyrinth of Gainclone posts (I tried a search too to no avail). What's the best earthing arrangement for a true dual-mono (two transformers & rectifier boards) Gainclone in the same chassis?
Many thanks!
- John
Many thanks!
- John
Found what I needed here post 714: http://www.diyaudio.com/forums/audi...l-gainclone-kit-building-instructions-72.html
And post 73: http://www.diyaudio.com/forums/audi...-kit-building-instructions-8.html#post1518369
Might be an idea to add both of these to the sticky for others using stereo and/or dual mono setups in same chassis?
😉
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Just to make things clearer for anyone building a true dual-mono Gainclone, but housed in the same chassis, Peter says:
"In case of dual mono, I would connect AC Earth ground directly to chassis first and then run CHG from each amp board to that point through 10R resistors each."
"In case of dual mono, I would connect AC Earth ground directly to chassis first and then run CHG from each amp board to that point through 10R resistors each."
That advice is potentially dangerous.
I'll explain why, because Peter takes exception to me posting on this commercial sector of the Forum.
Here's the scenario:
The mains Live wire breaks, or the mains transformer breaks and this failure results in a mains connection to some part of the secondary side of the amplifier. The audio side shorts out that high AC voltage to any route it can find back to mains Neutral.
That route will be via the PE wire in the mains cable.
How does the faulty mains voltage get to PE?
Via whatever secondary side connections to chassis that exist. Most of the amplifier is insulated from chassis. The Main Audio Ground is connected to chassis via PD's proposed 10r resistor.
The next part becomes the problem:
Mains voltage is trying to return to Neutral via PE and through that 10r resistor. 230Vac across 10r is ~ 5.3kW and could be >32Apk.
The resistor almost instantaneously overheats and then goes on to "frazzle" itself. This sequence of resistor failing to open takes just a few microseconds. This period is too short to reliably rupture the fuse fitted in the equipment nor to open the circuit breaker back at the distribution board.
Now the potentially FATAL part of the scenario:
The mains fuse is not open.
The Main Audio Ground to Chassis resistor is open.
The faulty mains connection to the secondary side makes all the internal components LIVE.
Those LIVE parts can be connected to other double insulated equipment.
Both the faulty amplifier and all the other (connected) ClassII equipment now have Mains voltage on the LV side.
Touching any conductive part of the LIVE equipment will kill you, or your child.
The Main Audio Ground Must be connected to Chassis by a route that can pass Mains Fault Current to PE and this route MUST survive long enough to ensure that the Mains Fuse ruptures and the arc extinguishes.
If PD only mentions that 10r resistor and makes no mention of the other "Fault Current" route components then he is wrong in advising only a resistor. A plain wire is safer.
But any Member should help themselves by reading all/some/many of the other Threads that discuss this topic and read the ESP site about this same subject.
Summary
The Main Audio Ground of mains powered equipment MUST be connected to Chassis.
This "Connection" MUST be capable of passing "Fault Current".
There are no exceptions in ClassI equipment, (all diy audio builds using mains power).
I'll explain why, because Peter takes exception to me posting on this commercial sector of the Forum.
Here's the scenario:
The mains Live wire breaks, or the mains transformer breaks and this failure results in a mains connection to some part of the secondary side of the amplifier. The audio side shorts out that high AC voltage to any route it can find back to mains Neutral.
That route will be via the PE wire in the mains cable.
How does the faulty mains voltage get to PE?
Via whatever secondary side connections to chassis that exist. Most of the amplifier is insulated from chassis. The Main Audio Ground is connected to chassis via PD's proposed 10r resistor.
The next part becomes the problem:
Mains voltage is trying to return to Neutral via PE and through that 10r resistor. 230Vac across 10r is ~ 5.3kW and could be >32Apk.
The resistor almost instantaneously overheats and then goes on to "frazzle" itself. This sequence of resistor failing to open takes just a few microseconds. This period is too short to reliably rupture the fuse fitted in the equipment nor to open the circuit breaker back at the distribution board.
Now the potentially FATAL part of the scenario:
The mains fuse is not open.
The Main Audio Ground to Chassis resistor is open.
The faulty mains connection to the secondary side makes all the internal components LIVE.
Those LIVE parts can be connected to other double insulated equipment.
Both the faulty amplifier and all the other (connected) ClassII equipment now have Mains voltage on the LV side.
Touching any conductive part of the LIVE equipment will kill you, or your child.
The Main Audio Ground Must be connected to Chassis by a route that can pass Mains Fault Current to PE and this route MUST survive long enough to ensure that the Mains Fuse ruptures and the arc extinguishes.
If PD only mentions that 10r resistor and makes no mention of the other "Fault Current" route components then he is wrong in advising only a resistor. A plain wire is safer.
But any Member should help themselves by reading all/some/many of the other Threads that discuss this topic and read the ESP site about this same subject.
Summary
The Main Audio Ground of mains powered equipment MUST be connected to Chassis.
This "Connection" MUST be capable of passing "Fault Current".
There are no exceptions in ClassI equipment, (all diy audio builds using mains power).
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Thanks for the above advice Andrew - I attached the main audio grounds direct to the chasss earth point, without the 10R resistors. Fortunately absolutely no hum that I can decern, otherwise I guess one then needs to implement the disconnecting network shown on ESPs website.
Extremely pleased with the end result - stunned in fact. These little chips really are quite something!
Thanks for your help Andrew.
John.
Extremely pleased with the end result - stunned in fact. These little chips really are quite something!
Thanks for your help Andrew.
John.
Perhaps a dumb question but I am not sure. I will change my gainclone tomorrow to a dual mono amp. But I am not sure how to wire the stargrounding. Only CHG from chipboard or also from the rectifier board (I now have grounding from CHG and pg+ and PG-)? My guess is the only grounding needs to be from CHG grom both chipboards.
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Like johnm I ran both chg to the chassis without any 10R resistors and had no bproblem with hum.No connection to the chassis from the power supply only to the amp board.
There's no common ground on rectifier boards (separate grounds for each rail which connect on amp board), so in your case just the wires from CHG for stargrounding.