Group Buy: Mauro Penasa MyRef Rev C kit

[kaushik]

Cool - where did you get the Panasonic 10,000 uF in Bangalore? I gave Anil the stock kit with Panasonic 6800 uF/50V, which is also the same in Captain Rajesh's kit. The stock Panasonics are good value for sure, but I'll probably be running out of those shortly, so I need to scout for good replacements.

shreekanth got them from some source..liked how the amp handled fast transients

 

[gobble]

Don't worry, I don't think there's any audible difference between 60:40:0, 63:37:0 and 62:36:2 Snb:Ag solder. Most of the differences relate to ease of soldering, wetability and flow characteristics. The silver solder is recommended for soldering on bare copper or gold, because the intermetallic compound between Cu:Ag and Au:Ag has good conduction as well as mechanical properties.

On another note, I forgot the most relevant mod to the MyRef kit: Use a high quality polypropylene film/foil input-coupling cap (C13) like a Solen, Obbligato, Mundorf or similar. Some of the Russian military-surplus Teflon, PIO and PETP caps on EBay are also getting good reviews.

You can use these to either replace or bypass the 4.7uF/63V film cap supplied in the kit. If you bypass it, you can use a small value like 47 or 100 nF without losing bass slam, while at the same time getting cleaner highs.

Talking in practical terms - how do I bypass this capacitor already in the PCB/Circuit.

I placed them on a table tried walking past a few times from left to right and right to left, ignoring them completely. there was no change in SQ. Then I realized, I had forgotten to switch on my stereo. Still no difference... somehow I am suspicious that is not what you meant ...

Cheers

 

[linuxguru]

I placed them on a table tried walking past a few times from left to right and right to left, ignoring them completely. there was no change in SQ. Then I realized, I had forgotten to switch on my stereo. Still no difference... somehow I am suspicious that is not what you meant ...

It depends - if you have played a lot of heavy-metal or oily music (say from the soundtrack of the movie Grease), then the wires and capacitors may get clogged and eventually blocked, and it won't allow the music to pass smoothly. Then you need to take the MyRef to a hospital and get an ECG and angiogram done to check if it needs a bypass - If necessary, the capacitors can then be bypassed. Sometimes, they say that a bypass is not necessary, and a balloon angioplasty or stent is sufficient to allow the music to flow smoothly again...

On a more relevant note, you just have to run two wires (one from each terminal of the on-board 4.7uF Panasonic ECQ (brown) input-coupling cap) to the two terminals of your bypass cap, say a 100..470nF Solen or Mundorf or whatever. You can use 2-core shielded wire for this, in which case you need to ground the shield to the signal ground near the input connector on the PCB. You should try to keep this cable run as short as possible to reduce the lead inductance.

Alternatively, if you have the space, you can solder the bypass cap on the bottom of the PCB and/or keep it adjacent to the edge of the PCB.

This is entirely optional, since the supplied Panasonic ECQ film cap is actually pretty good on its own, even on the highs.

 

[linuxguru]

Update: I'm still waiting for LM3886TF chips to come back in stock - they're virtually unavailable now at regular prices of Rs.200 or lower.

Until I get the chips, I can provide partial MyRef kits with the PCB + all the parts except the LM3886 - PM me for details. You can use any of the following chips on the MyRef: LM3886T, LM3886TF, LM3876T, LM3876TF. Only the LM3886T is now available in limited quantity in the market.

 

[captrajesh]

yes captain, very difficult to decide.
you better make room for all........ the amps I mean :lol:

Hi Hiten,

Neither of them can be kept in one room however big the room may be. I mean :lol:

It depends - if you have played a lot of heavy-metal or oily music (say from the soundtrack of the movie Grease), then the wires and capacitors may get clogged and eventually blocked, and it won't allow the music to pass smoothly. Then you need to take the MyRef to a hospital and get an ECG and angiogram done to check if it needs a bypass - If necessary, the capacitors can then be bypassed. Sometimes, they say that a bypass is not necessary, and a balloon angioplasty or stent is sufficient to allow the music to flow smoothly again...

:lol:I thought you are of a serious kind but pleasantly surprised with the sense of humour.

 

[Hiten]

Neither of them can be kept in one room however big the room may be.

They will never get along well with each other in the same room.
...... again I mean speakers and different amps

 

[captrajesh]

Hi guys,

The amp has been doing the duty of improving SQ of my kids' TV sound diligently for all these days and a detailed listening session was long overdue.

Yesterday, I invited my trusted old friend Sashi Kumar for a listening session. On the agenda was to audition the Amp as well as used Audio Quest cables that I had purchased from a forum member.

Took the amp out and connected it to the Marantz CD 6003 via a potentiometer. The CDP was having a CD from previous listening session "Tribute to RD Burman" which are basically re-recorded songs sung by Anuradha Podwal and Abhijeet (I think) and originally sung by Lata and Kishore.

The vocals, instrument separation, clarity are mesmerising. Gone are the harshness and tremendous slam. But the sound was very forward and very detailed.

We then played our old reference songs of Santana and Dire Straits. Wonderful sounding amp we concluded.

We then replaced the 16 gauge OFC cables with the Audio quest cable. This cable is from their flat series and each cable has two sheaths each having two single strands of copper wire.

The first thing that we noticed was that the sound has become more laid back and more refined. However, the immediacy of the OFC cable along with its forwarding sounding nature was gone.

After some listening, we went back to my new work horse, Luxman. We played Jimi Hendrix to see how it fares. The usually harsh and bright sounding electric guitar of Jimi never sounded so good. The session went on till 1230 A.M. An evening well spent, over a few shots of Blenders Pride.

This is an extremely good sounding amp and is a great way to begin the audio journey especially for guys on a shoe string budget. What it cost me is given below: -

1. Pair of PCBs with the associated components from Linuxguru - Rs. 3000
2. Cost of 24-0-24 V 200 VA Toroidal transformer from SV Troniks - Rs. 1200
3. Cost of populating the boards and mounting on a breadboard - Rs. 1500
(Including cost of internal wiring, speaker binding posts and pot)
4. Cost of heat sink - Rs. 150
5. Cost of female RCA plugs - Rs. 26

So for about Rs. 5876/- a newbie can have an amplifier which can give any of the main stream integrated amps a run for their money.

 

[crisscross]

Thanks for the detailed review captain. How do these compare to the CDA-254?

 

[gobble]

Thanks for the detailed review captain. How do these compare to the MoonPhase Pro-X98? Or the SolarAudio Extreme 45s?

Cheers

 

[linuxguru]

Captain, thanks for your detailed review. I believe it's possible to make the audible sonics of the MyRef even smoother and more fluid with a few component upgrades - which I mentioned earlier in the thread.

 

[captrajesh]

How do these compare to the CDA-254?

I find that the two are different species. Like Neandrethal and Homo Sapiens. Class D really excels in micro dynamics. It produces all the nuances of the mid range in sweetest of sweet presentations but is little lean on bass.

In comparison, the LM 3886 amp has typical Class AB character of being an alrounder. Good overall presentation.

I don't know if this is due to the transformer as some forum members have suggested. How is your Amp build coming along? Have you purchased the trafo yet?

How do these compare to the MoonPhase Pro-X98? Or the SolarAudio Extreme 45s?

The little red devil at work again ha.hyeah:

I believe it's possible to make the audible sonics of the MyRef even smoother and more fluid with a few component upgrades - which I mentioned earlier in the thread.

Will look into those surely.

 

[captrajesh]

I'm really upset with not being able to get a dead amp from Ritchie street and finding functional amps instead.

Some one suggested that I scout around Moore Market (Next to Chennai central) where I'm sure to get it but am told that they would be shady characters.

Any pointers guys on how to deal with them?

 

[captrajesh]

No one knows about Moore market??:sad:

I will take my chance and visit that place to check it out.

 

[captrajesh]

Hi Hemant,

It was nice talking to you today morning. I posted the pic of the amp here

I posted on the purchase of technics amp here

Hope I can get a dead amp somehow.

Rgds


Rajesh

 

[hemantwaghe]

Not to confuse anyone- Myself and captain had a discussion about Cabinets.It was not sort of some secret discussion!hyeah:hyeah

Basically captain is looking for junk amp just for "body" or casing.
Now I requested that give me minimum dimensions in which the assembled setup can be accomdated and airflow and cooling can be maintained.

Other members can also chip inn.

Basically many amps ae around 17 Inch Bredth ,2-3 Inch ( or Higher ) Height and 12 Inch depth.
Offcourse there are smaller amps so I need MINIMUM dimensions

Members can anyone help? Also anyone is having junk amp lying around ,can he donate? I am trying to procure but you know things in used market are not available when required!hyeah:hyeah: Also shipping will be an hassle.

Also thinking on another direction and thinking what alternates can be used

1) Metal Box ( large chocolate box) is there danger of electric shock?
2) Wood box ( Need holes in front and rear ,to accommodate swiches and connectors
3) Plastic Box

NOW HEAT MAY MELT/BURN WOOD AND PLASTIC RIGHT?

4) How about old pc case for time being?Available at kabadi ..or with many members ,can it be used?

Members please let the ideas flow..


Also can anu other audio gadget box can be used? like tuner or tape deck?

IN CHENNAI ANYONE HAS DONAR ITEM?( This "item" is nothing to do with "items "in "item song")hyeah:hyeah:hyeah:hyeah:

 

[captrajesh]

Hi

Thanks Hemant. Couldn't go to Moore market today.

Hope I'd get lucky tomorrow.

Rgds


Rajesh

 

[jls001]

but am told that they would be shady characters.

The shadier the dealer, the deader the amp ought to be:lol:

Capt, are u through with your Class D? Sorry, not been following this thread, but nevertheless interested in its stage of completion/incompletion, but more importantly, how it sounds. You located decent transformers?
Joshua

 

[captrajesh]

The shadier the dealer, the deader the amp ought to be:lol:

:lol:You are right.

Capt, are u through with your Class D? Sorry, not been following this thread, but nevertheless interested in its stage of completion/incompletion, but more importantly, how it sounds. You located decent transformers?
Joshua

Yes Joshua, I had made some time ago. It sounds pretty nice but the slam is missing. Don't know if that is due to the transformer. I'll have to source a good torodial trafo and check the result.

I found this thread after making the Class D amp.

You can see the picture here

You can read about a brief review here

Cheers


Rajesh

 

[crisscross]

I find that the two are different species. Like Neandrethal and Homo Sapiens. Class D really excels in micro dynamics. It produces all the nuances of the mid range in sweetest of sweet presentations but is little lean on bass.

In comparison, the LM 3886 amp has typical Class AB character of being an alrounder. Good overall presentation.

I don't know if this is due to the transformer as some forum members have suggested. How is your Amp build coming along? Have you purchased the trafo yet?



The little red devil at work again ha.hyeah:



Will look into those surely.

Hi captain. I have ordered the trafo but I also have a speaker build I need to do and was busy trying to get the inductors for those as well. I finally have everything ordered and should pick it up today/tom.

I am not sure if I can build it right away though.. I am taking the GMAT in sometime and that plus work is taking most of my time.

 

[captrajesh]

Guys,

Am I the only one who made this amp or are there more? Posting your pics and opinions would help new / late comers.