my_ref revC group buy (Mauro Penasa LM3886 design)

[AndrewT]

100VA will power between 50W and 100W of maximum output.
The disadvantage of the smallish transformer is the increased regulation. This does not reduce the maximum power output. But it does increase the voltage across the chipamp when either quiescent or playing quiet signals.
The down side of this is that the increased dissipation of the chipamp will make it run hotter.
The solution is easy. A bigger heatsink to keep the chipamp at the same temperature that the lower regulation transformer would achieve.
The solution for increased ripple due to the increased impedance of the smaller transformer is a bit more smoothing capacitance.
A commercial offering would not bother with either solution, all they want is maximum profit.
You have the choice. Be informed and make a choice that suits you.

 

[samsagaz]

Well, so to test the amp, will be OK to use the 100VA toroidals 🙂 after i collect some money and purchase an bigger one.


Btw in having some problems with the C4 and C5 Cap, i will try to see if have in stock other size from other kit that i purchased some time (i have a few at home that dont build yet).
if dont have it at home, i just need to curve the pin of the cap to try to reach the hole, right?

another one, the Blue terminals (the ones that have 2 holes to insert some wires), where i need to use it? 😀

 

[audiosteve]

I'm getting depressed reading all these posts of gleeful people receiving their kits. I missed the buy. If there is another buy planned or if anyone has a kit or kits they don't want, please let me know.

Thanks

 

[schro20]

Btw in having some problems with the C4 and C5 Cap [...]
another one, the Blue terminals (the ones that have 2 holes to insert some wires), where i need to use it?

Indeed, C4/5 as we purchased them have lesser spacing between their leads than what the board has. They go in just fine if you bend the legs carefully with needle nose pliers.

The terminal blocks are optional for use on the input and the LED. Some people like soldering directly others enjoy the terminal blocks... there is no specific need for them.

peter

 

[AndrewT]

it is always a good idea to place extra pads for all capacitors on a PCB, to allow for alternative pin pitch/s.
The next group buy could very easily incorporate these extra pads.

 

[samsagaz]

well, im just ready to connect the transformer, but i really want to ask before do it 🙂

the trafo are 220 / 25-0-25, how i connect it?

 

[udailey]

Sam, search for the "NEW MyREFc" thread. Its pretty short right now, but it shows even with pics and schematic how to do exactly what you are asking.
You will find it fast for sure.
Uriah

 

[samsagaz]

thanks

 

[dudaindc]

Got my stuff!

Peter & Uriah
I just returned from an overseas trip and found my kits and extra parts waiting for me.
What a wonderful job you guys made putting this together - you set the bar pretty high for other group buys!
I am not sure if I should wait until I finish unpacking before I turn the soldering station on... 😀
Thanks again!

 

[marc brown]

Re: color coded BOM

Attached is the BOM color coded according to the bags. Yellow is the capacitor bag (everything small is labeled EXCEPT for the 12 220nF bypass caps [small yellow boxes] which correspond to C7/17/18/19/20/21). Blue is for the resistor bag (everything labeled except for the big cement 0R47). The "silicon" bag is highlighted in pink here. Note that the nylon bushings are in that bag loose. So when you open the bag, be sure not to have those little buggers roll off under the couch...

Peter

I'm sure there were but I can't find them -- was there a post that gave assembly instructions or guidelines?

thanks for indulging my ineptitude 😕

 

[noodle]

Any chance someone would be kind enough to put up a pic/instructions for hooking up the "uriah" toroid? Poked thru the various threads and couldnt find anything that was suitable.

Thanks.

 

[troystg]

Can you post a picture of what you are calling the "Uriah" Trafo?

 

[marc brown]

Any chance someone would be kind enough to put up a pic/instructions for hooking up the "uriah" toroid? Poked thru the various threads and couldnt find anything that was suitable.

Thanks.

Here's a link to documentation from the manufacturer. Scroll down to the bottom of the pdf for connection information.

 

[jonclancy]

Thanks!!!

Peter and Uriah,

I collected my packages yesterday morning and am now back in the UK admiring your hard work! 😎

Many thanks for executing such a huge GB. I can only imagine the colossal amount of time and effort you put in on our behalf!

Awesome!!!

Jon 😀

 

[troystg]

Any chance someone would be kind enough to put up a pic/instructions for hooking up the "uriah" toroid? Poked thru the various threads and couldnt find anything that was suitable.

Thanks.

Noodle-

Did you get what you were looking for or do you need more guidance?

I am more than happy to help to my limited ability. If I don't know I can ask too!!

 

[noodle]

Kind of you to ask. More guidance please.
While the link was appreciated, it was still a tad above my level. Just a quick what goes where would be most appreciated. Am guessing there may be others in my situation.

Thanks

 

[troystg]

Kind of you to ask. More guidance please.
While the link was appreciated, it was still a tad above my level. Just a quick what goes where would be most appreciated. Am guessing there may be others in my situation.

Thanks

Was yours the ILP trafo?

2 white leads, ONE red, black, yellow and blue?

Look like this?

http://www.diyaudio.com/forums/showthread.php?postid=1730705#post1730705

If not post a picture of the torid you have please.

No worries we WILL get you hooked up (pun intended)!! 😀

 

[troystg]

Yesterday I brought the Rev_C to Mr. Gerald's for him to listen to it.

We took out a tube amp and put the Rev_C in it's place in his work shop system.

Source: Magnavox CD player rebuilt. Apparently the CD drawer mechanism is suppose to be good but the rest was all rebuilt.

Pre: Passive and tube 12au7 (or ua7) active

Amp: AES (Cary) set amp

Speakers: 6.5" two way, SS revelator mid-woofer, Seas softdome tweeter.

CD: Jennifer Warnes "The Hunter"

We listened to the system, swapped out the amp and listened to the same tracks again.

He liked the Rev_C more.. 😀

We swapped out the passive pre with the active tube pre and listened to the same tracks again..

We then swapped out the amps and put the tube amp back in..

That lasted 2 tracks and the Rev_C came back in...


Rev_C is killer for the money...

Then we went into his listening room and played the same tracks on his main system.

Well the Rev_C wasn't THAT good... 😀

ML 39 cd, ML 4x1 amp, Kimber Monocle XL spkr cable to his three way 10" speakers..

 

[gabanyayaya]

received the pcb last week just promised. Thank you uriah for such excellent job and friendly help. diy world need more helpful and friendly fellow like you...cheers.

 

[nania]

troystg
What did it sound like when you plugged the myref into Mr. Gerald's main system? Do you know what the lowest impedence dip is on his speaker system?