• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

BPA300 mono block

Status
Not open for further replies.
This is my part list for your reference :


Parts Quantity

Case, DRV134 kit x2
500VA Transformer x2
47000uF RIFA Caps x4
Heatsink x4
47k 1% x4
10k 0.1% x12
200k 0.1% x12
8pF x12
220pF x12
2200uF 63V Muse x16
0.1uF Wima x28
Dale 0.2ohm 3W SMD x12
LM3886 x12
2ohm 1W x4
Solen 10uF x4
VR 50k x12
3pin connector x 8
2pin connector x4
small 2 pin conn x4
Thermal Pad x12
 
The new PCBs are done.
newPA150-1.jpg



Notice the printed value of the 8pf capacitor is now correct.
newPA150-2.jpg



Close up :
newPA150-3.jpg
 
To Diyaudio members who confirmed the order :

The PA150 3x3886 PCBs are ready. Please email me with the following information and I will prepare the package and send you a paypal invoice.

- Number of PCBs you want to buy
- Shipment method (Registered Air Mail or HK Speedpost)
- Delivery Address
- Recipient name for the delivery
- Your Paypal account id (email)

If I receive your paypal payment on or before Saturday. I will mail it out on Monday (June 4th)



==========================
Shipping Info (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)
- 1-4 PCBs at USD 7
- 5-6 PCBs at USD 7.5
- 7-8 PCBs at USD 9
- 9-10 PCBs at USD 10

Hong Kong Speedpost
- estimated 2-4 days delivery (+ customs clearance time if any)
- 1-9 PCBs at USD 15.5
- 10-20 PCBs at USD 21
 
Rowland Implementation

Sorry for the late reply, I have been out of town. I have tried to attached the pdf file but the website keeps on telling me the file size is too big. I'll try to shrink it later tonight. Anyways, similar information can be found on Analog's AD815 datasheet, page 13/14

In order to run full balanced topology as in Coherence preamp, you'll need 2 Jensen transformers per channel and the costs add up fast. The newer Rowland preamp/amp use only 1 transformer to achieve full balanced operation.

If there are enough people interested in using the transformer to drive balanced BPA-300 board, I will e-mail AlexW88 the schematic (provided he doesn't mind and has time to play with the topology) and see where we can go from there.

Any words on the parts?
 
alex88 bpa300

who makes a truly stable variable resistor which we can use in this setup to adjust dc offset. it is a particularly close tolerance adjustment and long term reliablility would be nice. a group buy on the jensen transformers would be what 50-60 u.s. dollars apiece?????
 
Re: alex88 bpa300

tryonziess said:
who makes a truly stable variable resistor which we can use in this setup to adjust dc offset. it is a particularly close tolerance adjustment and long term reliablility would be nice.
the parallel set up is no worse than any other in output offset sensitivity.
The bridged is theoretically twice as sensitive but, since both amps are likely to drift in the same direction as temps vary, then I suspect it may turn out that overall it is less sensitive.

A normal sealed multiturn is adequate.
 
alex88 bpa300

there was a thread somewhere about a das modul amp. he used lm3886 chips which laid parallel to the pcb. anyone know what case style number that is. it would be great on alex88 pcb to lay the whole board against the sink with spacers. nice neat setup and efficient.:smash:
 
Status
Not open for further replies.