What are the symptoms? Do you have a hum problem? Or is the sound distorted?samsagaz said:maybe i need to use a few hours the amp to get it sound better 🙂
Peter
no noticeable HUM, i just when turn the vol up (from the PC), i get distorted the bass.
and with my other amplifier (other simple LM3886 design) i dont get too much disorted.
and with my other amplifier (other simple LM3886 design) i dont get too much disorted.
will test it tomorrow right now finished to solder the 2nd channel.
I have an question 🙂 R2 say that need to be < 12K but the R2 = 33K , is that ok?
:S
I have an question 🙂 R2 say that need to be < 12K but the R2 = 33K , is that ok?
:S
I thought that R2 was 33k and R12 was 3.3K as well as R37. Thats what the BOM I am looking at says.
Uriah
Uriah
Fuses?
Hi, need some help on fuses. Powered my kits up with a 40watt lightbulb in series with mains. Relayes klicked in ok and mesured dc on outputs -0,1 mV, 3.2mV. Fuses were T2,5 A.
When power up directly from the mains both fuses blew. Kit is powered by a single toroid 300VA 230V 2x25V. Noticed when I got it that it messured 120x65, 10 mm higher than from spec, wonder if this being a thicker core may impact on inrush current? Is it ok to use 3(?) or 4 A fuses? My memory says that 4A was a bit too much. Softstart?
I have checked for short between chip and heatsink, insulation is ok.
Thanks again Udaily and Peter for a great GB.
Took me 9 hours to build the kits.
Hi, need some help on fuses. Powered my kits up with a 40watt lightbulb in series with mains. Relayes klicked in ok and mesured dc on outputs -0,1 mV, 3.2mV. Fuses were T2,5 A.
When power up directly from the mains both fuses blew. Kit is powered by a single toroid 300VA 230V 2x25V. Noticed when I got it that it messured 120x65, 10 mm higher than from spec, wonder if this being a thicker core may impact on inrush current? Is it ok to use 3(?) or 4 A fuses? My memory says that 4A was a bit too much. Softstart?
I have checked for short between chip and heatsink, insulation is ok.
Thanks again Udaily and Peter for a great GB.
Took me 9 hours to build the kits.
Re: Fuses?
I started with 2 x 160Va trafo's on a 250mA fuse. Lasted the first pwr up but not the second.. I then went to a 5 A fuse and it is holding well. 5 A @ 120 volts here.. 5A @ 220 seems like an awful lot.. I wouldn't expect you to need more than 2-3 Amps. Softstart should NOT be needed for less than 400VA...
nenne said:Hi, need some help on fuses. Powered my kits up with a 40watt lightbulb in series with mains. Relayes klicked in ok and mesured dc on outputs -0,1 mV, 3.2mV. Fuses were T2,5 A.
When power up directly from the mains both fuses blew. Kit is powered by a single toroid 300VA 230V 2x25V. Noticed when I got it that it messured 120x65, 10 mm higher than from spec, wonder if this being a thicker core may impact on inrush current? Is it ok to use 3(?) or 4 A fuses? My memory says that 4A was a bit too much. Softstart?
I have checked for short between chip and heatsink, insulation is ok.
Thanks again Udaily and Peter for a great GB.
Took me 9 hours to build the kits.
I started with 2 x 160Va trafo's on a 250mA fuse. Lasted the first pwr up but not the second.. I then went to a 5 A fuse and it is holding well. 5 A @ 120 volts here.. 5A @ 220 seems like an awful lot.. I wouldn't expect you to need more than 2-3 Amps. Softstart should NOT be needed for less than 400VA...
Yeay. It's annoying. I don't know why it says that. The TP BOM is the one we followed.samsagaz said:The PCB say that need to be < 12K, its why i ask
Anyone know why it says that?
peter
schro20 said:
Yeay. It's annoying. I don't know why it says that. The TP BOM is the one we followed.
Anyone know why it says that?
peter
Why Rm in chipamps is better around 10K (Read from Post #54 to #60)
Also kits from Chipamp.com use Rm=10K
Is this guy made a clone of the Rev C do you think?
http://cgi.ebay.com/LM318-LM3886-ST...12050QQcmdZViewItemQQ_trksidZp1742.m153.l1262
http://cgi.ebay.com/LM318-LM3886-ST...12050QQcmdZViewItemQQ_trksidZp1742.m153.l1262
I think so. It looks like it might be the Evolution version or it could be the very original version. Either way the layout looks very good, nevertheless its a rip off for sure.
Uriah
Uriah
looks similar, and i see other products from this seller that are similar to other design too, is that legit? they dont go into troubles doing that? look this http://cgi.ebay.com.sg/STEREO-AUDIO...3911.c0.m14&_trkparms=66:4|65:3|39:1|240:1318
F5 Amp :S
F5 Amp :S
Well look what country its coming out of.
My buddy builds huge metal containers for recycling and trash collection. They have had China ask them repeatedly to buy a few of the containers. They wont sell them the containers because they know they will be reverse engineered and sold all over the planet for prices they cant compete with. Nope, you cant do anything about it cuz the Chinese govt doesnt really care.
Uriah
GUYS GALS,
I will be gone for two weeks. Funeral in the Midwest and visiting other family while out that way. Will check in from time to time but not often.
My buddy builds huge metal containers for recycling and trash collection. They have had China ask them repeatedly to buy a few of the containers. They wont sell them the containers because they know they will be reverse engineered and sold all over the planet for prices they cant compete with. Nope, you cant do anything about it cuz the Chinese govt doesnt really care.
Uriah
GUYS GALS,
I will be gone for two weeks. Funeral in the Midwest and visiting other family while out that way. Will check in from time to time but not often.
udailey said:I think so. It looks like it might be the Evolution version or it could be the very original version. Either way the layout looks very good, nevertheless its a rip off for sure.
Uriah
No, it's not Evolution, it's a bad copy with cheap capacitors and a poor board layout (did you see how far are PS caps from chips???).
Attached a photo of an original MyRef
samsagaz said:is that legit? they dont go into troubles doing that?
No, it is not legitimate, if they do not have the consent of the original designer. And they are also not allowed to copy company logos or name tags on their boards, like in the case of the Pass F5. They get away with it, because people are reluctant to sue them. The chinese legal system is a bit difficult for foreigners.
We are seeing a change in the chinese attitude towards copyright infringement lately. The last years they did not care as long as they could make money out of it. Nowadays there is a rising pressure on them from foreign companies and governments that do business there. And the Chinese seem to become aware that copying everything leaves the impression that they cannot come up with competitive designs of their own, which leaves them ashamed.
It's not right that's for sure. The best thing to do is NOT to buy from these guys and spread the word to anyone you know to avoid them as well. These people are the reason some of the designers will not share with us. Thank (deity of choice here) for great people like Papa who willing share there wonderful stuff. It really stinks to see such a blatant rip off.
udailey said:I think so. It looks like it might be the Evolution version or it could be the very original version. Either way the layout looks very good, nevertheless its a rip off for sure.
Uriah
No, it's not Evolution, it's a bad copy of MyRef with cheap capacitors and layout is different from the original Mauro's gerbers.
A photo of an original MyRef:
An externally hosted image should be here but it was not working when we last tested it.
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