Commercial Gainclone kit- building instructions

[masood]

Originally Posted by erikb1971

Parts lost?

Hi all

I plan to start soldering tomorrow. Knowing me, I was taking the parts out already to see if I had everything, since it is pretty me to lose vital parts. And it could be me, but it seems to me as if I have a bit too many of some, and too few of other parts. I have taken a picture of the content of the premium kit as I have it now. Could you guys take a look and help me out please? Tnx!

PS If it turns out some parts are missing, Iam sure they got lost here somewhere, I trust Peter a lot better with sending than I trust myself with storing.

Erik

dear all,
canany one share this pcb art work.thanking you masood

[bobfig]

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%.

[Overdream]

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 ???

[Peter Daniel]

Because the bare wire I'm using is only 26ga and not suitable for output connection.
I usually use Kimber 19ga for speakers.

[gille]

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.

[Peter Daniel]

Originally Posted by gille

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)

That is quite normal, the offsets have been explained here: Commercial Gainclone kit- building instructions

[piquadrat]

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

[Peter Daniel]

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?

[gille]

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

[piquadrat]

Originally Posted by Peter Daniel

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?

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

Originally Posted by gille

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

Lucky you. I have to be online at all time and want(-ed I'm affraid) to use this amp all day.