Group Buy: Mauro Penasa MyRef Rev C kit

[linuxguru]

What will the difference be between the Panasonic 6800uF in the kit and premium high-capacitance options, like the 18,000 or 22,000uF/50V Panasonic TS-UP ?

Actually, I don't really know. The 6800uF was good enough for fairly deep bass (~40 Hz and lower) on Capt. Rajesh's Kenwoods. Maybe for bass-heavy music at high SPL, like hard rock, hip-hop, disco, etc., there may be an advantage with the larger caps. It may also help to drive large-diameter woofer loads (say 12" or higher) at high SPL.

I just left it as an option for those who would like to experiment - it may well be the case that the overall sonics may be worse with a high-capacitance PSU filter, as compared to something in between, like 6800 or 10,000 uF.

 

[linuxguru]

Quick update: Just powered up the first Version 1.3 board and everything seems fine.

No smoke, everything cool/mildly warm to the touch, output offset is 1.6 mV (the lowest I've seen on any MyRef), Grateful Dead playing smoothly without issues.

I'll give further updates later today. Local DIYers are welcome to audition it (PM me for contact details).

 

[stereorules]

No smoke, everything cool/mildly warm to the touch

Thats good to hear....You sure spared the Bangalore sorry, Bengaluru Fire department ..:lol: Just kidding .. Nice to know that things are moving along nicely..Can't wait to build it.

 

[madvenu]

Hello All

Thanks to Linuxguru .. I have assembled a pair of MyRef v 1.3 circuits.

Tomorrow, I intended to test them..


Cheers
venu

 

[Hiten]

:thumbsup: Neat job Venu. All the best.
Where did you find the parts placement schematic ?

 

[quad]

Attaching the parts layout. Linuxguru made a few more tweaks after
this, but this should still be sufficient to get an idea.
Edit: Looks like the attachment is automatically resized by the site, so
even though I attached a bigger pic, it is showing up rather small.
Now added the larger image as a gzip file.

 

[madvenu]

:thumbsup: Neat job Venu. All the best.
Where did you find the parts placement schematic ?

I got the schematic from Linuxguru / Siva at his place ! Yes, he has started deliveries on the group buy ! It was cool to meet Siva and see the amount of work he has done in researching, redesigning the PCB, getting it done from China, sourcing all the components from various places etc.

And, when I had doubts, a quick email to him produced responses in 10 minutes, even at 10pm at night !!

Cool
venu

 

[linuxguru]

Thanks, Venu. That was quick work by you on the assembly! Make sure that you check and double check everything - placement, polarity, solder joints, connections, etc. before powering up.

 

[gobble]

Hello All

Thanks to Linuxguru .. I have assembled a pair of MyRef v 1.3 circuits.

Tomorrow, I intended to test them..


Cheers
venu

That was fast!! when I met Siva, you had not yet picked up your parts.. and I am still panning on next week ...

Where did you get the trafo from?

Cheers

 

[captrajesh]

Hi Shiva,

The trafo is ready. When are you coming to Chennai?

There are ppl waiting eagerly for your arrival.

Rgds


Rajesh

 

[madvenu]

Thanks, Venu. That was quick work by you on the assembly! Make sure that you check and double check everything - placement, polarity, solder joints, connections, etc. before powering up.

OK... powered up my first board and connected a car speaker to test.... It works so cool......

The noise floor is pretty low... even with the exposed cabling etc...

Tomorrow, will get the cabinet done.. and then.. the speakers from soundsgreat !

cheers
venu

 

[denom]

OK... powered up my first board and connected a car speaker to test.... It works so cool......

The noise floor is pretty low... even with the exposed cabling etc...

Tomorrow, will get the cabinet done.. and then.. the speakers from soundsgreat !

cheers
venu

:clapping: Enjoy

 

[gobble]

OK... powered up my first board and connected a car speaker to test.... It works so cool......

The noise floor is pretty low... even with the exposed cabling etc...

Tomorrow, will get the cabinet done.. and then.. the speakers from soundsgreat !

cheers
venu

Nice! Whats the source?

cheers

 

[madvenu]

That was fast!! when I met Siva, you had not yet picked up your parts.. and I am still panning on next week ...

Where did you get the trafo from?

Cheers

Hello Rahul...

Though I had the circuits ready last week... only today did I get the courage to power it up... straight from a 6.5amp 24-0-24 EI transformer. I searched on SP road at Bangalore last week and could not find one, till I called Siva and was rescued !

ciao
venu

 

[gobble]

Hello Rahul...

Though I had the circuits ready last week... only today did I get the courage to power it up... straight from a 6.5amp 24-0-24 EI transformer. I searched on SP road at Bangalore last week and could not find one, till I called Siva and was rescued !

ciao
venu

Searched on SP road for what?!! I meant what is your source CDP ...

I know you picked it up from Siva ...

Did you also search for a amplifier kit locally on SP road? I think thats what your post implies ... correct?

Isnt it safer to use a Variac when powering an amp for the first time ,and measure key readings before turning the voltage to a full 230V?

How much for a Variac on SP road? I need it anyways for my other projects ...

Cheers

 

[anilva]

How much for a Variac on SP road? I need it anyways for my other projects ...

Cheers

Variac on SP road? I have my doubts. Variacs usually are quite expensive and are based on the VA ratings, and they are toroidal (if you want continously variable type and not the stepped type).

 

[gobble]

Variac on SP road? I have my doubts. Variacs usually are quite expensive and are based on the VA ratings, and they are toroidal (if you want continously variable type and not the stepped type).

The step type should be fine right? Next time I go I will ask around.

How expensive is expensive?

Thanks

 

[anilva]

The step type should be fine right? Next time I go I will ask around.

How expensive is expensive?

Thanks

Minimum 4K and above for 1KVA variac type. I am also on the look out. At one point in time, I had access to over 40 of these units of different capacities (thanks to my dad's business).

 

[borg]

if your application is low voltage dc(like 24v-36 for the amps and other hobby electronic circuits), better option is to go for a continuosly variable dc powersupply in which you can adjust both voltage level and also have a variable current limit . Variac is usually useful for testing equipments working directly on line.

 

[captrajesh]

Hi guys

We've populated one board. Pic is enclosed. Shiva was kind enough to provide a diagram and has marked the changes.

Mathew Syriac, was has helped me by assembling the amp is our forum member is an experienced DIYer, having designed and developed his own 7 channel amp.

They have initially connected the amp to a 12-0-12 V trafo to avoid frying the amp in case of any wrong connections. Not finding any issues, (heating/hum etc) we decided to connect the amp to the main trafo 24-0-24 200 VA and to small bookshelfs.

Again no issues and hence we have connected to the source, Marantz CD6003. Played a track or two. It played on nicely.

We then connected to Torvin Two way tower. Tremendous slam, the amp was playing very cleanly upto 40% volume beyond which, there was some distortion. We then connected it to a Oscilloscope. We have noticed clipping
of signals with bass heavy content after about 40%.

Took it home and connected to the APs and my towers. One thing I noticed is this amp excels in lows with even drum sounds having much more texture, mids are a little lean, highs are ok. Ofcourse, my listening time was very limited. I'll post a detailed writeup sometime later.