BPA300 mono block

[Fenris]

Nothing wrong with EI cores - I use them in about 50% of my amps. They're bigger and have more potential for stray magnetic fields (and some hum), but they work just fine.

 

[alexw88]

So far we have :

Member # of boards
========================
HIPCHECK 6-10
Tryonziess 6
Alexcd 8
Analogdiy 6-8


Let's wait a couple more days to see if more members want to join...

 

[AR2]

Very nice and clean construction, Alex... But try to think about different input amp - DRV 134 have little bit " synthetic " sound...

I agree with this as well. What would you suggest Upupa? I would prefer discrete circuit, or even better tube. If Lundahl or Jensen could be used that would be the best and the simplest solution in my mind. They are around $ 90.00 last I checked.

 

[alexcd]

$90 per mono for a premium front-end is a bargain but wouldn't the input impedance be a tad low for non-active preamps?

Alex, would it help if I bought 4 more?

 

[alexw88]

For transformer at input you need to match impedance on both side. i.e. you need a low output impedance pre-amp (likely a active one) and a high input impedance at the PA150 PCB (which you need to change the 10k/200k resistors combo)

Don't worry about the magic number "40" I think we are close enough.

Member # of boards
========================
HIPCHECK 6-10
Tryonziess 8
Alexcd 8
Analogdiy 6-8

Total : 28-34

 

[alexcd]

The transformer sounds like an issue for me.

I'm going to need the DRV134 or similiar.

 

[HIPCHECK]

hey guys, just figured id let you know, I have talked to Alexw88 about getting started finding all the parts needed for the amp.

so far I will donate all 1% smd reesistors needed to parrallel the amps

If the 10uf solen is used for al the amps than we can get them @ $2.75 each x100 units. (avg price is $4.00 ish)

I would also like to know (and Im sure opinions will vary) what elec caps everybody would like. Panasonics FM/FC? Elna? Nichiconc? etc.

Is everybody happy with the Wimas (mkp?) (0.1uf)

Im waiting on an email about the 50k trimpots.

I would prefer to keep this OT, but if a parts order was made it would require some discussion of parts.

 

[alexcd]

Thanks for the effort hipcheck. Group buying all the parts would be a great idea!

 

[HIPCHECK]

it would be a huge cost per person to build this amp without buying bulk. I am just doing some digging right now, and if this buy goes active, maybe also we can buy parts together.

 

[alexcd]

I was just thinking.... 4 amps $$$$ yikes! If I can help track stuff down let me know.

 

[alexw88]

Thanks HIPCHECK for the Dale WSR 0.3R 2W 1%, they are hard to find and expensive.

 

[alexcd]

The power supply caps are a big ticket item. If everyone wants the same type and doesn't have their own, a decent amount could be saved in buying bulk.

 

[alexw88]

I have checked the shipping cost to US :

Shipping weight : 40g per PCB. Packing is about 150g.

Hong Kong Post Registered Air mail
- estimated 2-4 weeks delivery (+ customs clearance time if any)
- 6 PCBs at USD 7.5
- 8 PCBs at USD 9
- 10 PCBs at USD 10

Hong Kong Speedpost
Speedpost online rate calculator
- estimated 2-4 days delivery (+ customs clearance time if any)
- 6 PCBs at USD 15.5
- 8 PCBs at USD 15.5
- 10 PCBs at USD 21

 

[dudaindc]

BPA300 boards

Alex
I would be interested in four (4) boards.
Thanks!

 

[alexcd]

Panasonic FC are nice

 

[alexw88]

I got the quotation from the PCB maker and the price for each PCB is now at US$ 8.

Currently we have order from :

Member # of boards
========================
HIPCHECK 6-10
Tryonziess 8
Alexcd 8
Analogdiy 6-8
dudaindc 4


HIPCHECK and analogdiy, can you confirm the final number of boards you want to have? After I got your confirmation I will start the PCB order.

 

[ttan98]

I will take at least 2 boards. This is a firm order. My email address you can get it from this forum.

Once ready I will pay through paypal.

Please advise me when ready.

Thanks.

 

[Tex Houston]

PCB's

Hi there. Could i use your boards for a stereo set up? I'm imagining an amp utilising 3 LM3886 per side in a dual mono configuration. If that is feasible I would certainly be keen on a couple of boards.

 

[HIPCHECK]

A little bird in my ear informed me that 4 would be a good amount for me, funny I really thought 8 was my magic number

so 4 boards it is, sorry to blow up the count then lower it down.

 

[alexw88]

Re: PCB's

Hi there. Could i use your boards for a stereo set up? I'm imagining an amp utilising 3 LM3886 per side in a dual mono configuration. If that is feasible I would certainly be keen on a couple of boards.

Yes, you can do this. That means you just do parallel with no bridging.

so 4 boards it is, sorry to blow up the count then lower it down.

No problem btw, any update on your parts search?