Mod your Beresford TC-7510

[kalozois100]

I tried a pulse transformer on PC spdif output to DAC earlier and I have to report that in my system it seemed to make absolutely no difference to the sound, which was a shame. Transformer was free though so not lost anything I guess.

Just waiting for new op amp to arrive to try out on DAC output now. .

I found replacing the JRC4558 with LM4562MA made a vast improvement to the sound.

[NRG]

I tried a pulse transformer on PC spdif output to DAC earlier and I have to report that in my system it seemed to make absolutely no difference to the sound, which was a shame. Transformer was free though so not lost anything I guess.

Just waiting for new op amp to arrive to try out on DAC output now. If that doesn't make any difference to the sound then I shall have to assume my ears are broken.

Sorry to hear that. Does the card have an output TX already? How did you implement the cct? Did you remove the existing o/p cct? What tx did you use, they can be quite specific?

[ultraviolet]

No output TX just a line driver (I forget which one) with an RC circuit on its output. I tried 2 transformers - one was custom made by one of the switch mode PSU engineers at work and the other was salvaged from an old network card. I just connected to TX to the output - but with no blocking cap on input or resistor on output. I could try cap on input - I presume it stops the core saturating if theres any DC present. I assume the resistor on the output is only doing anything if no cable is connected.

I deduce that either the output was fairly clean anyway or the 7510 is not particularly sensitive to the signal quality on the SPDIF input. I could dig 'scope out and have a look at the waveforms but I prefer to listen for improvements rather than try to measure them.

[StanleyB]

the 7510 is not particularly sensitive to the signal quality on the SPDIF input.

The re-clocking cct takes care of business over a wide bandwidth and phase error range.

Stan

[NRG]

...and yet I found a worthwhile improvement implementing the pulse tx cct on the o/p of the SB...

[StanleyB]

...and yet I found a worthwhile improvement implementing the pulse tx cct on the o/p of the SB...

Good for you.

[NRG]

....and picking up on this I've now got two SPDIF outputs from my Squeezebox to the 7510 DAC allowing AB test between the output from the pulse cct above and from the output of the Tent Labs X03 board. The Tent labs output is poorer on the scope and in practice also sounds worse...splashy treble and worse separation and definition (in comparison), so I believe there is mileage to be gained with this cct.

[kalozois100]

Regarding the maplin power supply:
When i received the maplin power supply i connected it with 13.5volts setting to the tc-7510 and had listened since on that setting. a friend suggested i try it back on the 12volt setting and after having done so i found the sound to be much better. I don't think my speakers could take the massive bass that the 13.5volts setting seems to produce . Also mids and highs seemed alot more defined. I don't know why i have experienced this phenomenon when others have found the 13.5 v setting better. another variable may be due to the replacement opamp from the one fitted as standard in the tc-7510. Anyway what matters is the better audio i'm getting so a suggestion to others is to try both 12v and 13.5v and for them to see which best suits their set up.

[Covenant]

Stan has advised me that he will have an inexpensive linear supply available in March some time.

[trailer]

Well having settled down listening (very happily I must add) to the 7520 I had a thought "What should I do with the now unused 7510?"

After a bit of conversation with Stan and viewing posts on here I decided to get the op amp changed out along with the capacitors for some Black Gates. The DAC has been replaced with the recommended Wolfson one. Total cost for the parts about twenty quid.

It is due back to me at the end of the week. The only downside to this? I'm out of the country for a couple of weeks so I'm afraid that I won't be able to give it a listen till then

It will be really interesting to compare it to the 7520.

Next step? 7520 hot rodding?