Mod your Beresford 7520

[therockst4r]

James: I have replaced my opamps and some caps, and I agree that the improvements were very noticeable. I started with the 47uf caps rather than the 100uf ones though. Please keep us informed with your upgrades, as I am interested in doing similar tweaks.

[Shanedudddy2]

Have you guys at all modified the circuit board with the 2 opamps on them... seems like it would be a hard place to access and fix it back up...with the silicon all there, has anyone done that... or just left that alone?
Plan to do some capacitor mods myself, anyone think any resistor upgrades would be worthwhile too?

[Beechwoods]

a little word on my system

Hi James! Great first post It's great to have you aboard. Have you thought about posting some pics of your system over in the Gallery? Or some pics of your projects in the DIY Gallery? It'd be interesting to see your stuff!

[jcgrant]

hi guys thanks very much,

so far the mods for the beresford have cost about £20/ 25 euro.
That includes the the wolfson , and all the 47uF and 100uF caps . The only reason I fitted the 100's first was because they arrrived in the post first from Switzerland, the 47's are coming from Hong kong so they are a week or two away still (thank goodness for flea-bay) . I really really want to change the big cap but as of yet can't justify the £15 +delivery from the Hi-fi collective shop.

The 100 caps have given the bass a lot more depth its almost too overpowering but i expect that to settle down after a week or so failing that I can always cheat and use the tone control (at least i know its there for any parties/if i want to piss the neighbours off )

I notice quite a few people here are using a maplin power supply I might be interested in this for a quick and easy route to better sound .The beresford has what i think are two voltage regulators and from what i can read i think they are 7810(don't quote me on this just had a quick look) or 10v the other may be a 5v one for the chips. This would make sense having a 12v supply as most voltage regulators need an input at least 2v above they're ouput. I'm not sure if the beresford uses the raw 12v dc from the supply to power any of its circuits , if it does it would be better to regulate this as well at the power supply.

I will take some photo's of my stuff and hopefully put them on the gallery, when I've found my way round the site.

Thanks guys once again .

[trailer]

I think the Maplin PSU only really benefits the 7510

[therockst4r]

Have you guys at all modified the circuit board with the 2 opamps on them... seems like it would be a hard place to access and fix it back up...with the silicon all there, has anyone done that... or just left that alone?
Plan to do some capacitor mods myself, anyone think any resistor upgrades would be worthwhile too?

I replaced all the caps on that board and swapped out the opamps with some THS4032CDs, but that is it. I think you will probably notice the cap upgrades more than resistor upgrades, but I could be mistaken.

[lemon]

The change of resistance does not improve the sound, there are good resistors inside to 7520, all are metal resistance.
If you want to improve your 7520 around the opamp, then:

1) If you do not use the variable output, remove the variable opamp.
2) certainly change the dac-chip with the Wolfson 8716 (the major change).
3) change the signal capacitors with other best.
4) note that bigger supply voltage affects only the operator of variable output, the fixed output opamp is fed constantly to 10V because of 7810.
5) Experimen with a supply of batteries. The battery is free from noise. The best solution is to 5V battery power directly to the digital part (without 7805) and the section of the opamp power battery 10V & 12V

[Shanedudddy2]

Do you have a picture of how you have implemented the battery aspect, you would remove the big input cap correct?

[lemon]

Don't remove the big input capacitor.

The series of input voltage is fisa->diode->current security (blue)->10000uF caps.

At first try to find a battery like 12V of UPS and then feed the 7520. How is it?
Then if you like it, remove the diode and current security (blue) or bypass them.

The best solution with batteries or only one battery is to feed each part of 7520 with the pure DC without the 7805 & 7810 voltage regulators.

You can to make another rail for DC pure and compare the two feeds.

I am sorry but my English isn't very good! A very good link is http://www.diyhifi.org/forums/viewto...afc228c2162b81

[jcgrant]

i also changed the caps on the driver board and then took out the uprated op -amp , just to hear the sound difference - put the uprated opamp back in the wrong way round and blew the op amp up, d'oh,ah well 8 quid for a new one !! not even for attemping the wolfson upgrade to tricky for my shaky hands may get it done in the new year after the stack of partys i have lined up for the festive period!
the caps make ad difference just slighly worth the couple of quid they cost and they tinkering was good .

i hope to put some pictures of my system up soon once i find my camera!!