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BuildMeSomething BuildMeSomething is offline

diyAudio Member

About Me

  • About BuildMeSomething
    Location
    North West, UK
    Interests
    Audio diy & music, photography, mountain bikes, home cinema
    Occupation
    LGV Driver
    Country
    United Kingdom
    Real Name
    Paul Blythe
  • Signature
    Listening with Gusto!

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General Information
  • Last Activity: 29th June 2014 07:42 PM
  • Join Date: 23rd October 2011

Blog

Latest Blog Entry

Posted 1st June 2013 at 11:24 AM by BuildMeSomething Comments 0
Posted in Uncategorized
Well, this little project is finished and working. Quite pleased that measured offset dropped to <1 mV on both channels once the amp was in the chassis and wired.

Listening impressions: This is where I state that it's the best amp I've listened to, and it is... Unfortunately, it just highlights any shortfalls with the speakers. The Mission 773e have never performed better or sounded clearer. However, you are just as aware on how quickly these speakers lose the plot with more complex music... In the long run I hope to match the sound of the Sennheiser HD-650 driven by "The Wire" se-se HPA, the FH3 are my first try at achieving this...

Paul

Posted 17th May 2013 at 07:09 PM by BuildMeSomething Comments 0
Posted in Uncategorized
Well, this project is nearing completion. The very last pieces needed have been ordered and will be delivery early next week. The chassis and custom PCB enclosure/heat spreader were collected on Thursday morning from FedEx and UPS. Thursday night was spent drilling and tapping holes for the various parts. Now its some wire placement and waiting on the last pieces...

Problems: None really, a few sizing issues for connecting wires and the caps to the boards. Though, all are just big enough with a little patience. Certainly no issues that require a halt to the project or new PCB's.

Speakers: Decision made, Frugel-Horn Mk 3 with Mark Audio Alpair7.3 drivers... Why? I love the strong imagining and detail given by the little 3" FC full range speakers, so thought I'd give some proper full rangers a go. Should be fun trying to build these

Posted 28th April 2013 at 03:04 PM by BuildMeSomething Comments 6
Posted in Uncategorized
The Amp boards arrived Saturday, unfortunately, I was just leaving for work so they'd have to wait. Everything looked OK on them.

Initial power up test was done with both LME49990 in place but only one LME49600 mounted on each channel [PSU used was a modified "The Wire" unit meant for testing the A/B Power Amp at +/-25Vdc, now set at +/-15Vdc. It was getting quite hot as it was dropping 10V per rail]. That went Ok, so the rest of the 49600 were put in place and powered up once more... Again, everything OK.

Measured offset:

Left channel: 27mV
Right channet: 8mV

Foam board speakers are progressing, and will be ordering a heatsink this week also.

Update [13-04-30]: Been a little bit worried about the higher offset value on the left channel, though it's not at a bad level overall. Once the amp has been on awhile, it appears to settle at 25.9 mV.

Made a quick SE input>volume pot AC coupled...

Posted 19th April 2013 at 09:49 AM by BuildMeSomething Comments 0
Posted in Uncategorized
Holiday: Bad weather to a point it was near impossible to take a steady photograph due to the gusting winds. Hiding from the winds meant poor vantage points, very much non-idealistic for photographing landscapes.

Digi-key: The order turned up on the Monday morning, roughly 10 minutes before leaving. The PSU boards must have arrived mid week, a neighbour had those...

The parts order was enough components for one power supply and one amp. The PSU is assembled but untested as yet. The toroidal and 10K Alps RK27 are to be ordered from RS Components later today.

PCB issues: C1-C6... this is where trusting the people who generate default libraries for FreePCB falls down and my inexperience shows. Lead diameter on the caps is 28MIL, default part through-hole diameter is 28MIL... Each lead needed a quick file to reduce its width enough to fit the board. No other issues to report.

I don't think I could have made the overall size of the board...

Posted 9th April 2013 at 09:06 PM by BuildMeSomething Comments 0
Posted in Uncategorized
Power supply boards are on their way, as is a full Digikey order for this project. However, no LME49722, which are currently out of stock. Due to that and wanting to keep to a 1 x psu & 1 x amp layout, the amp board underwent a quick re-design. It's now duel mono layout, utilising two LME49990.

Ordered LT1033/LT1085 for the PSU, these should give 3A each [typical]. Plus, six 4,700uf caps to help out. The plan is to run the rails at +/-15Vdc, with a 120VA 2x15V toroidal transformer.

Will place an order for the prototype amp boards on Saturday, just before I go on holiday.

Update (13-04-11): The PSU PCB's still haven't arrived, Plus UPS failed to deliver my Digikey order, this is now in limbo as they're saying "A correct street name is needed for delivery" ... I've talked to both Digi-key & UPS (U.S.) and they have the correct full address, UPS (UK) I can't get hold of... my translation is "Delivery driver can't read a map!"...
Recent Comments
Ground planes are great...
Posted 30th April 2013 at 02:03 PM by abraxalito abraxalito is online now
All food for thought......
Posted 30th April 2013 at 09:21 AM by BuildMeSomething BuildMeSomething is offline
My initial thinking...
Posted 30th April 2013 at 03:17 AM by abraxalito abraxalito is online now
My guess is that it...
Posted 29th April 2013 at 11:06 PM by fas42 fas42 is online now
The simple answer is...
Posted 29th April 2013 at 09:11 PM by BuildMeSomething BuildMeSomething is offline
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