Group Buy: Mauro Penasa MyRef Rev C kit

[linuxguru]

Update: I got the first quotation for the PCB from PC Process today, and the NRE charges are too high. So I need to find a Plan-B quickly, and I need some pointers. Who is a reliable manufacturer of double-sided PTH PCBs, who can work with Gerber and Excellon files, in Bangalore? The quantity is 50-100 PCBs of size approx. 100 sq.cm. each.

I'm looking for NRE charges below Rs.3k and rate per PCB below Rs.300, without immersion-gold plating (the gold-plating is probably what sends the quotes shooting up).

Has anybody worked with:

1) Shiltron, Peenya
2) Sharp Line Circuits, Jalahalli
3) Any other alternatives?

I need to close on this quickly - the PCB is what has been dragging the schedule back, while almost everything else is on track. Any help/pointers would be appreciated.

Edit: I think I've got a workable plan B, though the immersion gold-plating may have to go. If I get the target pricing of Rs.300 + amortized NRE even with the gold, I'll keep the gold - will post an update over the weekend if I get the data.

-Siva

 

[quad]

The Miracle standard-product M22550 225VA, 2 x 25V, 4.5A will fit the bill.

If the cost difference is not too much, it might be desirable to go
in for the M30050 toroid.

 

[captrajesh]

Update: I got the first quotation for the PCB from PC Process today, and the NRE charges are too high. So I need to find a Plan-B quickly, and I need some pointers. Who is a reliable manufacturer of double-sided PTH PCBs, who can work with Gerber and Excellon files, in Bangalore?

I'm looking for NRE charges below Rs.3k and rate per PCB below Rs.300, without immersion.
3) Any other alternatives?

Any help/pointers would be appreciated.

Hi Siva
Im doing a govt funded project & Im told Blr doesn't have quality suppliers in low volumes. We get it made in Ahmedabad. Costs 80 paise per sq cm. If interested, can share the info
Rgds

Rajesh

 

[gobble]

If the cost difference is not too much, it might be desirable to go
in for the M30050 toroid.

Is the O/P column in miracle site the continuous current or peak?
-: MIRACLE :-

30050 looks like a better choice to me.

Does the quality of iron used matter? Someone mentioned that Miracle uses really poor quality iron. Grain orientation only matters for EI core right?

Which one of Delta/Miracle/Salzer uses M1 to M6 grade iron?

-G

 

[borg]

Is the O/P column in miracle site the continuous current or peak?
-: MIRACLE :-

30050 looks like a better choice to me.

Does the quality of iron used matter? Someone mentioned that Miracle uses really poor quality iron. Grain orientation only matters for EI core right?

Which one of Delta/Miracle/Salzer uses M1 to M6 grade iron?

-G

grain oriented core is better regardless ei or toroidal (i am saying from a transformer performance pov, not sure about the audio impact)

 

[linuxguru]

Im doing a govt funded project & Im told Blr doesn't have quality suppliers in low volumes. We get it made in Ahmedabad. Costs 80 paise per sq cm.

That price is really, really good - it would translate to ~Rs.80 per PCB. Are you sure this is for double-sided, PTH with solder-masks and silkscreen?

The lowest firm quote I have at the moment is Rs.3.2k NRE + Rs.215 per PCB, with red solder-mask, but without immersion gold pads. I'm inclined to omit the gold, since it has no real function except aesthetics - it's going to be soldered-over anyway on the solder-side. The gold jacks up the price per PCB by a huge amount.

If I can't improve on this price by Monday, I'll bite the bullet and close the deal without the gold, since it's close to or within my target of 3k NRE + Rs.300 per PCB.

 

[captrajesh]

That price is really, really good - it would translate to ~Rs.80 per PCB. Are you sure this is for double-sided, PTH with solder-masks and silkscreen?

The lowest firm quote I have at the moment is Rs.3.2k NRE + Rs.215 per PCB, with red solder-mask, but without immersion gold pads. I'm inclined to omit the gold, since it has no real function except aesthetics - it's going to be soldered-over anyway on the solder-side. The gold jacks up the price per PCB by a huge amount.

If I can't improve on this price by Monday, I'll bite the bullet and close the deal without the gold, since it's close to or within my target of 3k NRE + Rs.300 per PCB.

Hi Siva

Just back home. I don't know the technicialities. I've PMed you his telephone numbers. You can call & discuss. Alternatively you can PM me your number & I'll pass it on to him.

Rgds


Rajesh

 

[gobble]

some more options for Tranny

PowerCap
SVTronics

PowerCap makes R-Core Trannies which may be better for audio apps http://www.diyaudio.com/forums/power-supplies/151927-r-core-transformers-poor-choice-amp-psus.html

http://www.transformersindia.com/r-core-transformers.html All relevant certifications available http://www.transformersindia.com/why-us.html :licklips:

HTH

 

[gobble]

The case for R-Cores KITAMURA KIDEN Co LTD R Core & products information

 

[captrajesh]

Hi Linuxguru,

I'm told by the guy working on my project that a good quality Green PCB without Gold plating would cost Rs. 230/- excluding taxes (approx 15%)

Gold plated PCB with Red masking would cost about Rs. 320/- excluding taxes.

Both the above costs includes NRE charges.

He was mentioning that there appears to be a minor error in the Gerber file.

He was suggesting that we make about 2 to 4 sample PCBs, populate and test them fully before committing for making 100 Nos as if there is any error, the entire lot has to be discarded.

This is a very valid suggestion and he is speaking from experience and i vouch for it as one of my modules' PCB was all wrong. We could detect it at the sample stage itself and minimise the losses.

Per sample PCB of ordinary quality would cost about Rs. 400/- which in 100 nos volume would cost about Rs. 120/-

Regards


Rajesh

 

[linuxguru]

.
.
He was suggesting that we make about 2 to 4 sample PCBs, populate and test them fully before committing for making 100 Nos as if there is any error, the entire lot has to be discarded.
...
Per sample PCB of ordinary quality would cost about Rs. 400/- which in 100 nos volume would cost about Rs. 120/-

Good points - My plan is to source ordinary-quality PCBs locally and populate and test a few before going for the higher quality one in larger quantities. In case the ordinary quality PCB is good enough in fit and finish, that can itself be used for the volume product.

I have a firm quote of Rs.215 + Rs.3.2k NRE for 50 PCBs at the moment, but there's one more local source with a lower budgetary quote. I'm just waiting for confirmation from him.

I've clarified on the Gerber errors to Vinod. In case they are not able to work around the zero-width aperture issue, I'll rework the layout and Gerbers to get rid of that aperture.

-Siva

 

[captrajesh]

I have a firm quote of Rs.215 + Rs.3.2k NRE for 50 PCBs at the moment

Great going Siva. That would mean Rs. 279/- per board. Is it including taxes?

 

[linuxguru]

Great going Siva. That would mean Rs. 279/- per board. Is it including taxes?

I didn't close on this one, although they're nearby - the setup charges (NRE) seemed too high.

I did manage to close an order for 50 PCBs, through Uriah, with his Chinese vendor - lead times are of the order of 2 weeks + shipping delay. The first PCBs will probably arrive by the 1st-2nd week of September, and I hope I can clear them through customs quickly. The Chinese PCBs may end up being a bit more expensive, but probably of better finish than the local ones. This is Plan A, which should be fine, even if it's a bit delayed from the original schedule.

Meanwhile, as a backup Plan B, I also ordered 20 more PCBs through another, possibly lower quality, local vendor, but I don't have confirmation or even a payment request from them. If Plan B works out, i.e. if the quality is acceptable and the lead times are short enough, then all the future PCBs may end up being from this vendor.

To summarize: By early to mid-September, I should have 50 PCBs on hand which should suffice for all the existing kit requests, plus a cushion of 20 locally-sourced bare PCBs for those who may want to source parts and/or experiment on their own.

On the parts front, I have most of the passives and should not have any difficulty in sourcing the ICs and semis for the first 50 kits. There is a shortage of a couple of capacitor values, but those can most probably be substituted:

1) 150 pF Silver Mica or NP0/C0G ceramic - only 8 on hand, can probably get 20 more locally.
2) 22 pF Silver Mica or NP0/C0G ceramic - about a dozen on hand.

All izz well, except for the schedule slippage.

 

[denom]

Thanks for the update Siva. Now what about finalising the rest of the components like Trafo, casing, switches/LED's, Vol Pot....

 

[captrajesh]

I didn't close on this one, although they're nearby - the setup charges (NRE) seemed too high.

The figure of 279 was inclusive of initial charges I guess.

I did manage to close an order for 50 PCBs, through Uriah, with his Chinese vendor - lead times are of the order of 2 weeks + shipping delay. The first PCBs will probably arrive by the 1st-2nd week of September, and I hope I can clear them through customs quickly. The Chinese PCBs may end up being a bit more expensive, but probably of better finish than the local ones. This is Plan A, which should be fine, even if it's a bit delayed from the original schedule.

Are you sure of the quality Linuxguru, my project guy says that Chinese quality is highly unreliable.

Meanwhile, as a backup Plan B, I also ordered 20 more PCBs through another, possibly lower quality, local vendor, but I don't have confirmation or even a payment request from them. If Plan B works out, i.e. if the quality is acceptable and the lead times are short enough, then all the future PCBs may end up being from this vendor.

What about the Ahmedabad guy? Trust me his PCBs are of very good quality.

Could you also update on the plan of making 3-4 sample pieces for testing?

 

[linuxguru]

.
Are you sure of the quality Linuxguru, my project guy says that Chinese quality is highly unreliable.

What about the Ahmedabad guy? Trust me his PCBs are of very good quality.

Could you also update on the plan of making 3-4 sample pieces for testing?

The Chinese vendor supplied the PCBs for the previous two Twisted Pear group buys on DIYaudio, and they're of good quality - I purchased the version 1.2 PCBs from the last group buy.

The Ahmedabad guy has a regular lead time of 20 working days which translates to about 28 calendar days or almost a month. If you need accelerated delivery, his rates go up and are even higher than P C Process in Peenya, or the Chinese vendor.

The 3-4 sample pieces were to be from local vendor Orion - who quoted me a price, I confirmed quantity, and didn't hear anything back from them. They're the Plan B. The schedule for building a Version 1.3 test prototype still depends on the lead time from Orion, and how quickly this deal can be closed. If it doesn't happen, I'll have to wait for the Plan A PCBs to arrive.

However, I have several finished boards using the Twisted Pear version 1.2 PCB - which is not completely irrelevant since it uses an almost identical schematic as my version 1.3 PCB, and an identical BoM. These are what I'm using for testing, checking cabinet clearances, cabling, etc.

 

[captrajesh]

Hi Linuxguru,

Great to know your plans and the updates. Keep it up.:thumbsup:

 

[Hiten]

Any updates ? :licklips:

 

[linuxguru]

Any updates ?

1) Still waiting on the PCBs - Plan A from China will probably be the earliest arrivals.

2) The 150 pF capacitors have been procured - I went with Wima FKP2, same as in the Ultimate BoM on DIYaudio.

3) I managed to squeeze two assembled Version 1.2 Twisted Pear monoblocks into a vintage Bevox amplifier case from 1978. I'll post pictures later, as it is still work in progress, but it is a perfectly workable solution - and the transformer on the Bevox is barely 100 VA! I auditioned some Jagjit Singh, Shivkumar Sharma, Bach, and Led Zeppelin this evening on it - the source was a Denon DVD-2500 DVD player, and the speakers were the original Bevox speakers from 1978 (2 x 6" woofers, 1 x 2.5" tweeter each).

It may not have sufficient juice for heavy metal and hard rock, but 100VA is perfectly adequate for classical, vocal and light pop/rock.

 

[Kittu]

1) Still waiting on the PCBs - Plan A from China will probably be the earliest arrivals.

2) The 150 pF capacitors have been procured - I went with Wima FKP2, same as in the Ultimate BoM on DIYaudio.

3) I managed to squeeze two assembled Version 1.2 Twisted Pear monoblocks into a vintage Bevox amplifier case from 1978. I'll post pictures later, as it is still work in progress, but it is a perfectly workable solution - and the transformer on the Bevox is barely 100 VA! I auditioned some Jagjit Singh, Shivkumar Sharma, Bach, and Led Zeppelin this evening on it - the source was a Denon DVD-2500 DVD player, and the speakers were the original Bevox speakers from 1978 (2 x 6" woofers, 1 x 2.5" tweeter each).

It may not have sufficient juice for heavy metal and hard rock, but 100VA is perfectly adequate for classical, vocal and light pop/rock.

Good going Siva, eagerly waiting for you to build an amp for some heavy metal and hardrock... I'll be the first one to take it :yahoo: