Giving away Mauro Penasa MyRef. amplifier PCBs

[linuxguru]

@Gobble: Sure, we'll audition this after my return from Chennai - I'll build a few LF01 prototypes here with slight changes to figure out the optimal BoM.

@Rupy: The specs and all details of the amp are on various threads on the chipamps forum at diyaudio.com. Please check it out, and I'll be happy to answer specific queries at my e-mail: [email protected]

 

[Hiten]

Hello everyone,
I would like to give PCBs to Joshua.
Borg, Santhosh, cmsajith, adarsh, neeraj and everyone, thanks a lot for showing interest.
I also thank Siva (LinuxGuru) for working hard on this amp and making new version available to DIY Community.
Regards

 

[jls001]

Thanks a million for your generosity, Hiten. I shall make this board sing with further help from you.
Joshua

 

[adarsh]

Thanks Hiten. This journey of DIY will be a learning experience for me.

 

[jls001]

Finally got the boards today. They are a fair bit smaller than what I had envisioned in my mind's eye. No worries, thought.

Some progress report:
Have requested linuxguru (shouldn't he be renamed circuitguru:lol:?) for the premium kit. Hopefully he should be able to dispatch it early next week.

Had a lengthy chat with magma and concluded that even his cheapest cabinet design is too fancy for this build. Can upgrade later if sound warrants it.

Will go hunt for an el cheapo mild steel affair from good 'ole Lamington Road. Also need to buy a nice 240-250-ish VA, 24-0-24V toroidal. Any suggestions on a good brand? Is pure mono config of two separate transformers too much for this application? I am just dreaming out aloud. Do feel free to drag me down to earth if I fly too high

Also need following, and therefore actively soliciting advice on brand/model (pricing info would be a real bonus):
1. good pair of binding posts - MX or Spectra will do or should I go for the jugular and look for WBT?
2. RCA female pair - will try for gold plated Neutriks, or at least Amphenols. I do know a shop that deals with a Japanese brand I can't recall.
3. IEC male - need something sturdy.
4. Sturdy power switch
5. internal wiring - gauge, type, approx qty - is solid core desirable or overkill?
6. good quality logarithmic pot of about 25 kOhms for volume control. Any idea what is a good model/brand in stepped type attenuator? Would something like an ALPS be overkill, or will it be in keeping with the rest of the premium BOM?
7. Pot extender - may be 6-9 inches (I think). Are these things available readymade? Or do I need to cut it to length? I don't love the hacksaw too much.
8. Hex bolts for mounting circuit boards - what length would be suitable?

Too many questions for one day! But all pointers and advices welcome. And thanks in advance,
Joshua

 

[magma]

Will go hunt for an el cheapo mild steel affair from good 'ole Lamington Road. Also need to buy a nice 240-250-ish VA, 24-0-24V toroidal. Any suggestions on a good brand? Is pure mono config of two separate transformers too much for this application? I am just dreaming out aloud. Do feel free to drag me down to earth if I fly too high

Also need following, and therefore actively soliciting advice on brand/model (pricing info would be a real bonus):
1. good pair of binding posts - MX or Spectra will do or should I go for the jugular and look for WBT?
2. RCA female pair - will try for gold plated Neutriks, or at least Amphenols. I do know a shop that deals with a Japanese brand I can't recall.
3. IEC male - need something sturdy.
4. Sturdy power switch
5. internal wiring - gauge, type, approx qty - is solid core desirable or overkill?
6. good quality logarithmic pot of about 25 kOhms for volume control. Any idea what is a good model/brand in stepped type attenuator? Would something like an ALPS be overkill, or will it be in keeping with the rest of the premium BOM?
7. Pot extender - may be 6-9 inches (I think). Are these things available readymade? Or do I need to cut it to length? I don't love the hacksaw too much.
8. Hex bolts for mounting circuit boards - what length would be suitable?

Too many questions for one day! But all pointers and advices welcome. And thanks in advance,
Joshua

trafo from here
http://maps.google.co.in/maps/place...69,Mumbai,+Maharashtra&cid=221322648628227262

1. MX is fine for this build - the imported Taiwanese one is a bit expensive at 1000 bucks or so - you could try that
2.rca- MX import
3.IEC and power switch - availble at lamington
5. no idea
6.you get at alps pot made by phillips- decent quality - i have one lying around - you can have it if you are going for a pot
7.Pot extender these used to be avaible ready made . difficult to find now.Try the lane adjacent to grant rd bridge.you will also get your swiches and readymade cab there.Only if you dont find these contact me - i probably have a few lying around somewhere - i had them made in Non magnetic SS for some clients.Mine are a bit expensive again compared to readymade ones you may find
8.Use hex threaded spacers that are used in PC mobos. 10mm is a good height.these are affixed to the amp base with M3*8 or M3*5 screws depending on base thickness and then use M3*5 screws to affix the PCB board to the hex spacer from the top.You will find these sold in packets opposite spectra ( street vendors)

 

[linuxguru]

8.Use hex threaded spacers that are used in PC mobos. 10mm is a good height.these are affixed to the amp base with M3*8 or M3*5 screws depending on base thickness and then use M3*5 screws to affix the PCB board to the hex spacer from the top.You will find these sold in packets opposite spectra ( street vendors)

Good idea - I think you mean the brass ones with female threads on both sides. The PC mobo brass spacers are usually male on one side (to screw onto the cabinet base-plate) and female on the mobo side.

 

[gobble]

<Ignoramous Alert!!> I thought ALPS was a brand. How can Philips make an ALPS?

Maybe a group buy of Alps Blue/RK27 would help the community? I can buy using Borderlinx if people are willing to share the cost.

--G0bble

 

[sachu888]

Finally got the boards today. They are a fair bit smaller than what I had envisioned in my mind's eye. No worries, thought.

Some progress report:
Have requested linuxguru (shouldn't he be renamed circuitguru:lol:?) for the premium kit. Hopefully he should be able to dispatch it early next week.

Had a lengthy chat with magma and concluded that even his cheapest cabinet design is too fancy for this build. Can upgrade later if sound warrants it.

Will go hunt for an el cheapo mild steel affair from good 'ole Lamington Road. Also need to buy a nice 240-250-ish VA, 24-0-24V toroidal. Any suggestions on a good brand? Is pure mono config of two separate transformers too much for this application? I am just dreaming out aloud. Do feel free to drag me down to earth if I fly too high

Also need following, and therefore actively soliciting advice on brand/model (pricing info would be a real bonus):
1. good pair of binding posts - MX or Spectra will do or should I go for the jugular and look for WBT?
2. RCA female pair - will try for gold plated Neutriks, or at least Amphenols. I do know a shop that deals with a Japanese brand I can't recall.
3. IEC male - need something sturdy.
4. Sturdy power switch
5. internal wiring - gauge, type, approx qty - is solid core desirable or overkill?
6. good quality logarithmic pot of about 25 kOhms for volume control. Any idea what is a good model/brand in stepped type attenuator? Would something like an ALPS be overkill, or will it be in keeping with the rest of the premium BOM?
7. Pot extender - may be 6-9 inches (I think). Are these things available readymade? Or do I need to cut it to length? I don't love the hacksaw too much.
8. Hex bolts for mounting circuit boards - what length would be suitable?

Too many questions for one day! But all pointers and advices welcome. And thanks in advance,
Joshua

You will find everything @ Digikey.com, shipping is $40 to India,but you can always use shop and ship route.You can find an old car amplifier for enclosure. Some more cheaper options here.
Digi-Key

Regards,

Sachin

 

[grubyhalo]

My thoughts:

1. good pair of binding posts - MX or Spectra will do or should I go for the jugular and look for WBT?: I'd probably go for something in between, like a good Neutrik or a CMC
2. RCA female pair - will try for gold plated Neutriks, or at least Amphenols. I do know a shop that deals with a Japanese brand I can't recall: Same as above
3. IEC male - need something sturdy.: The best I could afford.
4. Sturdy power switch:Same as above.
5. internal wiring - gauge, type, approx qty - is solid core desirable or overkill?: Line level wiring would probably be 24AWG pure copper solid core, speaker level would be the same as the speaker cable, probably a Mogami or a Belden.
6. good quality logarithmic pot of about 25 kOhms for volume control. Any idea what is a good model/brand in stepped type attenuator? Would something like an ALPS be overkill, or will it be in keeping with the rest of the premium BOM? I'd probably get the best I could afford and would not go lower than the Blue Velvet for the premium build.

Also, my line of thinking for the chassis is a little different from yours. I'd probably get the best possible chassis in a universal size with decent heat-sinks, RCA's, IEC's switches and swap the innards if I find a better amp design...

 

[omishra]

trafo from here
Beco Electronics

7.Pot extender these used to be avaible ready made . difficult to find now.Try the lane adjacent to grant rd bridge.you will also get your swiches and readymade cab there.Only if you dont find these contact me - i probably have a few lying around somewhere - i had them made in Non magnetic SS for some clients.Mine are a bit expensive again compared to readymade ones you may find

Why don't you help us for Cases and pot extender? I am looking forward on this.

 

[Hiten]

Will go hunt for an el cheapo mild steel affair from good 'ole Lamington Road.

Joshua, I will suggest first you assemble the pcbs with all critical components required to test the amp like transformer, heatsinks, pot etc. on a wooden board assemble all the things, double check on solder joints and see any points very close are not shorted, test with cheap 8 ohms speaker. Take precaution with loose live wires from transformer better insulate them. let it run for some time. if everything OK then take dummy size for every parts (transformer, connectors, pcbs) and look for enclosure. In Western Mumbai there are lots of UPS/Inverter Manufacturers (Thanks to power cuts ) see if any horizontal readymade cabinet is available. If possible take only top and bottom of the enclosure and for front facia you can take al. sheet and with proper markings can arrange vol. pot and power switch.
Search Result for inverter enclosure

 

[kaushik]

DIY Pot extender -- take looong screwdriver break the handle ,
cut a pen piece put pot shaft one way , other way screw driver metal
do 'super glue 'to fit, and onthe other end same thing with glue and knob , done

 

[quad]

Tantia Electronics

Look for a 60 Amp closed electrical connection block like the one
in the image. About Rs 50 only.
The brass insert inside makes a wonderful and cheap
shaft coupler with dual set screws - no need for glue etc.
And you get three of them, when you buy one of those blocks.

Also, you can get 6mm HDPE rod for about Rs 10 per foot.
It is non-conductive and makes an excellent extension shaft.
Aluminium rod is also about the same cost, if you prefer that.

 

[quad]

This is a nice pic of the brass insert from the terminal block,
which I mentioned in the previous post for the shaft coupler.
It should have a hole of just over 6mm dia.

 

[viki_v2]

Hello Hiten, Got any Pcbs left.

 

[Audiodoc]

Linuxguru is selling pcb's as well as kits. Don't know about hiten?

 

[Hiten]

Hello Hiten, Got any Pcbs left.

Sorry Viki I only had one set of stereo pcbs.
As audiodoc said PM Linuxguru.
Regards