Group Buy: Mauro Penasa MyRef Rev C kit

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Thanks to Linuxguru a group buy (PCB + Components) of an amp kit which went for Rs. 7000 to Rs. 8000 in DiyAudio was made available cheap for Indian DIYers, if I remember correctly Rs. 3000 value for money kit, that too with improved signal and ground traces on the pcb. I think he spent his own money and efforts just to test and run simulation on this amp, not an easy job.
 
Sent PM to Venkat & Madbullram. Venkat responded promptly and promised action. Madbullram was busy in some family function I was informed.
 
Thanks for the support from DIYers across the board - I just saw the thread and also the PM informing me of the rules violation. I have no problem about getting in compliance with hifivision's rules - it says I have to be a "registered seller" to promote or sell items on the forums, but there seems to be no way to become a registered seller online, or I missed it. I'll do what I can to register as a seller, if necessary.

Anyway, I'm still unwell and recovering slowly, so a 2-3 week schedule slippage is likely. I noticed that we've crossed the threshold of 10 stereo kits (20 monoblocks), so the group buy is fine shape. Bhyrav (Quadtech) had some changes to the layout which I'll try to merge in.

Regarding the trafo, it's possible that the 24-0-24V, 5A toroidal is part of the standard products line-up from Miracle or Salzer. These might be less expensive than custom-wound toroidals. You can also consider dual 24-0-24V, 2.5 or 3A windings, which might be cheaper.
 
Hey Siva

How easy or trivial or difficult is it to make this into a higher wattage amp?

Thanks
 
How easy or trivial or difficult is it to make this into a higher wattage amp?

The easy way is to use +/-35V rails, which will give you a few more watts (say around 50W+ / channel). This should be more than you should ever need - it's not meant to be a ghetto-blaster driving automotive-grade sub-woofers.

The other way is to buy a fully-loaded Evolution board (the successor to MyRef) directly from Mauro Penasa himself. It uses 2 x LM3886 per channel, and gets into the range of 100W+ /ch with appropriate rail voltages. I haven't checked the prices lately, but it used to run upward of 200 Euro per stereo board, semi-assembled.
 
The easy way is to use +/-35V rails, which will give you a few more watts (say around 50W+ / channel). This should be more than you should ever need - it's not meant to be a ghetto-blaster driving automotive-grade sub-woofers.

The other way is to buy a fully-loaded Evolution board (the successor to MyRef) directly from Mauro Penasa himself. It uses 2 x LM3886 per channel, and gets into the range of 100W+ /ch with appropriate rail voltages. I haven't checked the prices lately, but it used to run upward of 200 Euro per stereo board, semi-assembled.

I will stick with your version. The components will withstand the higher voltage/current? Just by using a correctly spec'ed Trafo, this can be achieved or do resistor/cap values change?

Is the GC known for a refined and delicate sound? Will it change and sound brutish if I pump it up? I want it to stay refined ...

I havent had time to check out the reviews and views of GC yet. Will try and do that this weekend.

Cheers
 
I will stick with your version. The components will withstand the higher voltage/current? Just by using a correctly spec'ed Trafo, this can be achieved or do resistor/cap values change?

Just needs a slightly higher-rated trafo - 26-0-26 should do it, instead of the stock 24-0-24. All other components have sufficient margin.

Is the GC known for a refined and delicate sound? Will it change and sound brutish if I pump it up? I want it to stay refined ...

It's refined enough at the stock rail voltages of +/- 32 V, which is what I'm using. It's reputed to sound slightly sweeter at +/- 28V, due to some known sonic artifacts of the LM3886.

I havent had time to check out the reviews and views of GC yet. Will try and do that this weekend.

It's not at all like a stock LM3886 gainclone, although they're often very good. The MyRef has the sonic character of the LM318, combined with the power and dynamic range of the LM3886. The Evolution is reportedly even nicer, with no perceptible sonic colouration at all.
 
Hi Linuxguru
Can the LM318 be replaced easily ? just curious.
Thanks
 
siva,good to see u offering this for a group buy and know many will benefit from this.kudos.also,hope ur getting better from ur recent bout of 'viral'.prayers.just cant thank u enough for for hosting our merry band(from kerala,and others) that evening at ur beautiful house,with music and sumptuous food as well.will cherish that memory,thanks a zillion.warmest regards to jeya and,cheers
 
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Can the LM318 be replaced easily ? just curious.

It's usually socketed in an 8-pin DIP socket, so it can be easily replaced. However, the Rev C circuit has compensation networks that are closely tied to the LM318 internal design, so it's not at all easy or recommended to try to roll op-amps with different types - at the very least, some components will have to be changed. In practice, the LM318 has excellent sonics coupled with a very respectable slew-rate, so there's no real need to try to roll op-amps.

You can, however, experiment with different manufacturers of the LM318 - AFAIK, the NatSemi and TI versions are identical, but the Fairchild and Linear Technology versions may not be exact drop-in replacements.
 
siva,good to see u offering this for a group buy .... for hosting our merry band(from kerala,and others) that evening at ur house,with music ...

Thanks - however, your host was somebody else (maybe Siva of Corrson?).
 
In practice, the LM318 has excellent sonics coupled with a very respectable slew-rate, so there's no real need to try to roll op-amps.
Yes. I read Mauro Penasa's thread where he said LM318 has Tube like sound. Hope you have recovered fully. :)
 
Good initiative and good luck to all the buyers. Not reached a stage where i can appreciate the upgrade and get one for myself.BTW, a similar initiative for a good dac kit like audiosector or similar dac will have many takers including myself.
 
Good initiative and good luck to all the buyers. Not reached a stage where i can appreciate the upgrade and get one for myself.BTW, a similar initiative for a good dac kit like audiosector or similar dac will have many takers including myself.

Why will you not be able to you appreciate it? Whats your current setup like?

Cheers
 
Gobble, Thanks for asking man, too much tech stuff for me to comprehend, i have a nad c320bee and wharf 9.2, could you please throw some more light? Meanwhile, i would go thro the thread to know more about the product. Still, i'd be more interested in a diy dac for now.

Why will you not be able to you appreciate it? Whats your current setup like?

Cheers
 
Any progress on this guys ? It maybe rude to ask this knowing that the OP was sick etc....but since I opted in last, didnt want to be left out ...
 
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