Sjöström Audio DIY forum

Projects => Headphone amplifiers => Topic started by: Houghtkj on March 17, 2012, 03:21:23 PM

Title: QRV-08 Parts Selection
Post by: Houghtkj on March 17, 2012, 03:21:23 PM
Hi, I'm just putting together a shopping list for a QRV-08 and one or two items are causing a bit of trouble.

1. The transformers appear to be very difficult to obtain in the UK and I can't find an alternative to the
one specified that fits the pcb. Shipping costs to the UK from Elfa are outrageous - Can anyone help?

2.  Capacitors C/G 27 and 28 - 2200uF/35v - Schematic shows 2 off each = 4400uF - Is it OK to fit one
big cap, say 4700uF?

3. Can someone suggest an alternative for the 100nF, 50V, 5%, PPS from Farnell - Closest I can find is this: http://uk.farnell.com/jsp/search/productdetail.jsp?sku=1855059 - It's not 2220 footprint (it's 1913), but will it be OK?

Any help will be much appreciated.

Ken
Title: Re: QRV-08 Parts Selection
Post by: peranders on March 17, 2012, 04:11:20 PM
1 Farnell 1214602. The Myrra type is a but wider but should fit.

2 Yes

3 No problem to use a smaller cap.
Title: Re: QRV-08 Parts Selection
Post by: Houghtkj on March 17, 2012, 06:12:22 PM
OK, many thanks P-A

I had seen that transformer, but the pin spacing is not the same - I guess I could hack it though and drill
out a couple of holes and link the pin to the pad under the pcb.

Thanks again for your rapid response.

Ken
Title: Re: QRV-08 Parts Selection
Post by: peranders on March 17, 2012, 07:29:09 PM
Sorry, I don't notice the difference in pin spacing between the primary and the secondary windings. I think you can manage this without too much work.
Title: Re: QRV-08 Parts Selection
Post by: Houghtkj on March 22, 2012, 06:00:40 PM
Hi P-A,   I am going to add a front panel LED when I case up the QRV08 - Can you please suggest a
suitable connection on the board that will not upset anything (power or audio)?

Thanks.
Title: Re: QRV-08 Parts Selection
Post by: peranders on March 22, 2012, 07:57:26 PM
You can take the unstabilised voltage. Start with that.