tc 7510 mods

[robyonekenoby]

Hi folks,

I wanna post my mod to this well known dac

replaced psu caps with 3 panasonic FM 2200 uF
replaced 1716 decoupling cap with sanyo OSCON SP 100 uF 10V + .33 uF MKT
replaced opamp decoupling cap with rubycon ZA (ultra low ESR) 100uF 35V + .33 uF MKT and the cap behind with one panasonic FM 1000 uF
added 2.2 uF MKT to bypass both 7810 and 7805
replaced opamp with AD8620
replaced opamp output cap with mundorf mcap 4.7 uF 400V
replaced opamp input cap with mundord mcap 2.2 uF + rubycon ZA 22uF 35V
replaced opamp FB caps (C5 and C6) with 1nF MKT; I've had to increase value from the original 220pF to 1nF to smooth out the over brilliant and sharp ad8620 sound signature

the result?

coupled with my DIY amp based on tripath TA2020

AMAZING !!!

deep, warm and rock solid bass, clear and open midrange, super detailed highs

the sound stage is spectacular, I can not just listen the music, but also look at the instruments materialized in the air, loudspeaker simply disappear
hours listening at volume high enough to disturb neighbour without any ear fatigue, just an unlimited pleasure

for the first time in my life classical music make sense to my ears, is alive, full of energy

I've just a question for you experienced guys: I replaced also the ceramic cap above the opamp with a .22uF MKT; is probably the V+ V- bypass I guess, but I'm not sure about the effect of different capacity

the larger the better or whatelse?

[James G]

Roby, I love what you've done with it! I bet it does sound great. I wish I could give you advise on your question, but I'm just taking my first steps into DIY. Your mods are much more inspired than mine. Well, here's a bump anyways.

Would you be so kind as to maybe add the pcb labels to the parts you changed for a newbie like me? For instance, I'm not sure about the location of the 1716 decoupling cap. Also, we love photos, if you have any you'd like to post. Thanks!

[robyonekenoby]

Sorry I don't remember the number on PCB, I'll check next time I reopen the cabinet to make some new mods (thinking to replace all polyester with Wima film and foil)

Anyway it's easy to identify the capacitor to replace: is the only small electrolytic (black, hermei brand) beside the 1716 chip

I prefer don't post any picture because after many soldering & desoldering, destroyed and rebuilt pcb tracks, capacitor leads in middle air, the result is not a nice seeing

[James G]

Anyway it's easy to identify the capacitor to replace: is the only small electrolytic (black, hermei brand) beside the 1716 chip

Ahh, ok. I know which one you're talking about now. Thanks.

I prefer don't post any picture because after many soldering & desoldering, destroyed and rebuilt pcb tracks, capacitor leads in middle air, the result is not a nice seeing

I know what you mean. Mine is getting that way too. I'm the guy that made the "wrecked my Beresford" thread after all.

It's just that I've suddenly taken a keen interest in all this stuff, and I just can't let it alone. Guess I just need to have patience.

[James G]

When you say "replaced opamp input cap with mundord mcap 2.2 uF + rubycon ZA 22uF 35V", how exactly do you implement that? Do you just solder both caps together on each side? Why would you need to add the poly and the lytic together?

The opamp input caps are EC4, EC5 right? The ones below the opamp?

Sorry for so many questions.

[robyonekenoby]

exactly, the two tiny lytics below the opamp, but pay attention, there are 4 caps below the opamp, the two inner are power decoupling caps, the two outer are the signal input coupling cap, the stock is 22uF hermei

As everybody know, lytics are not good for coupling (except MAYBE blackgate and elna), a good polypropilene film is a big improvement on every aspect

First I replaced them with two mundorf mcap 2.2 uF, but I discovered the capacitance is too small and I've lost bass weight, so I put in parallel the two rubycon 22uF to increase capacitance and restore bass extension

With this combination I have good detail in midrange and highs plus tight and deep bass

But I'm wondering the little lytics are introducing a minimum amount of distortion anyway, so I'm going to replace everything with single mcap 10uF

Also I've decided to replace the output caps, swap the mundorf for Audyn MKP plus film and foil

Tweaking hifi I've learned that replace signal coupling caps (also tweeter cap in speaker crossover) is the most effective way to improve sound quality

The second best is replace power decoupling caps for much lower ESR

[James G]

Thanks Roby, you're a champ for explaining that to me. So running the polys in parallel restores frequencies lost by the lytics! Nice.

I'm going to the electronics store today to see what I can find.

[FireFly]

What is difference between 7510 and 7520 models?

For op-amp rolling check link bellow. I agree 110% with this.
http://www.head-fi.org/forums/f5/lit...olling-304261/

Sign-up at www.linear.com and ask for some free samples
LT1364 is good choice, way better than LM4562.

[robyonekenoby]

Today I replaced the 2.2uF mcap + 22uF rubycon ZA with a single mcap 4.7uF for the opamp input coupling

Well, the bass is a bit less heavy but still acceptable (I'm convinced 10uF is the right value here) but all traces of harshness are gone now, so I could remove the 1nF caps in the output filter

So in my opinion the AD8620 is not a 'metallic and harsh opamp' as many people suggest, but being a very fast, accurate and precise opamp, you must pay attention to what you feed in, because it accurately reproduce and amplifies also HF noise and distortion coming from input electrolytics caps, while a slower opamp like the 4558 acts like a low pass filter

Would be my pleasure if some expert of this forum comments this statement

Maybe I'm wrong, but my ears told me I climbed another step up to the nirvana

[leo]

Maybe I'm wrong, but my ears told me I climbed another step up to the nirvana

I don't think anybody could argue with that, as long as your ears are happy