Mod your Beresford TC-7510

[leo]

I am using the 5532 in the 7510+. I got little time for people who work out the theory but don't try out a component in the circuit it is intended for. Decades of fault finding and circuit modification has taught me a lot about when to abandon theory and use one's ears instead. A bumble bee can't fly after all according to the theory.

The LM4562 is being used by quite a few people in their modification of the TC-7510. I also know of one guy who uses a double OPA627 on a Brown Dog adapter.

The PCM1716 can also be replaced by the WM8716, but there are two extra track mods that are required in order to get it to work properly. The WM8716 hasn't got the analogue filter built in like the PCM1716.

Totally agree! I once modded a cdp, a guy listened to it and said bloody hell! thats great! what op-amps you put in it? I said it uses the supplied NE5532's he then pulled a face like he had a shit smear under his nose

I think theres another chip from Wolfson (as well as 8716) thats pin compatible with the PCM1716 too

[leo]

I shall now teach you guys the best way to desolder a suface mount IC.
1. Get a Stanley knife with an absolute spanking new blade.
2. Press down gentle on each IC leg of the IC with the sharp tip of the blade till the blade has cut through the leg. It is important that you press down on the leg! Don't try it any other way.
3. Once you have cut out all the legs, whip the IC out.
4. Use a soldering iron with a flat end on the tip.
5. Rest the tip on each of the cut out leg that is still soldered to the PCB for about 2 to 3 seconds.
6. Now move the solder tip in the direction of where the IC body used to be. This will dislodge the soldered leg. Because there is no soldered component in the area where you just swiped the iron tip towards, the leg will not stick to any adjacent part.
7. If you lift the tip up now, in most cases the leg will still be stuck to the iron and you can then clean it off on a wet sponge.
8. The area from which you just removed the IC should now be cleaned with something like meths or so. Then you can just put the new IC in the same space.
9. Press down on each leg with the flat end of the solder iron tip for about 3 seconds. When you lift the soldering iron tip up the IC leg should now be soldered onto the PCB as if by magic.

Notice that at no time did I mention to use solder to solder anything. All donations are most welcome.

Nicely written and especially ideal for removing stuff thats been soldered with that lead free solder

[Mike]

I see the 7510+ as a specialized product that would be more of interest to people who want something close to Chord64 like performance at less than £200.

Now *THAT* should be something interesting indeed!

[StanleyB]

I am not interested in 'me too' product designs. I like pushing the boundaries of the impossible and watch the grins on the faces of the competition turn into long faces. It reminds me of when I designed the first touch screen handset that cost less than £100 and that I stacked up against the then £3000 Lexicon touch screen handset. Harrods ended up selling more than 1000 pieces and Elektopack didn't do too bad with them either. And they told me beforehand that I would never be able to take on a £3K handset. Cambrdige Audio later sold it as the M1.

[NRG]

Are the ALW's stable driving those big caps on the 7510's DC input Neal?

Good idea supplying the dac and op-amp with better regs, just a shame the ALW's are so big

It appears so Leo, I've not noticed or spotted anything on the 'scope to suggest other wise...those caps could go I suppose...

Yes the ALW's take up space and I'd probably be looking to re-house the DAC or go for a two box design.

[StanleyB]

It appears so Leo, I've not noticed or spotted anything on the 'scope to suggest other wise...those caps could go I suppose...

If you got a set of speakers with 12 inch or larger drivers, try out some bass heavy tunes with and without those caps in circuit.

[leo]

It appears so Leo, I've not noticed or spotted anything on the 'scope to suggest other wise...those caps could go I suppose...

Yes the ALW's take up space and I'd probably be looking to re-house the DAC or go for a two box design.

If the ALW's are stable then I wouldn't worry too much, its just that normally these work better with low capacitance on their output

The ALW's are funny things and sometimes can be picky where you use them

[trailer]

Would there be any benefit in disabling the headphone/pre-amp circuitry if you only use the DAC and the fixed outs?

[leo]

If I had one of these I'd be tempted to take out the headphone amp and fit a circuit in its place that could be used as an alternative output stage, you then have two different outputs
Makes comparing against the standard one easy

[StanleyB]

Would there be any benefit in disabling the headphone/pre-amp circuitry if you only use the DAC and the fixed outs?

I tried that and found that it made a difference. I mentioned this to one of my customers who is also a dedicated modder. This is what he replied:

1) LM4562MA op-amp to replace the NJM4558.

2) Since I don't use the variable output or headphone output, and my amp inputs have blocking caps (pp), I removed the 7510 output blocking caps (CC1, CC2 and the electrolytics) and put in a wire link. I also cut the "R" and "L" wires linking the output to the second board to stop the DC signal getting there.

3) Replaced the switching supply with a linear supply and replace the large DC supply electrolytic caps with high quality low-ESR types.


Stan