[taisho_daniel]

Thanks for the welcome and the replies folks.

Anyway, I had a moment to think about things, and then I realized I made an embarassingly stupid mistake.

I had used thoppa's pictures as my sort of guide book on how to plug in the Vanguard. Instead of using a socket tho, what I did was flip the chip over (pins up in the air) and hot glued it into place. My original idea was just to use blue tack, tho the repair guy assured me the hot glue was safe.

Anyway, I had the chip flipped over, but I attached the wires as if I hadn't. No wonder things went wrong.

I just had to resolder the wires, reinstall the essence st drivers, and now everything's back to normal.

Well, sorta. On the sample tracks I've played, I notice this odd sort of ringing like effect during relatively loud passages involving the upper frequencies. Weird.

 

[thoppa]

Hi,

That could be the xo physically vibrating ? How much and how and where did you use the hot glue ? Photo pls ? Actually, I have to say, it doesn't seem like a good idea. The hot glue has quite a lot of energy in it that it dissipates as it goes hard. The Vanguard is TXCO = temperature controlled XO. It's a precision bit of kit. Personally, I used a socket so I could avoid applying any heat to the xo in any way.

I also wonder if the ringing might be something to do with the cap changes.

 

[taisho_daniel]

Yeah, on hindsight I should've kept a closer look at what the tech was doing and stopped him from using the hot glue. Oh well, no use in crying about spilled milk. ^^


So far, I think I can rule out the caps in the power section and the XO upgrade as the cause of my problems. I switched to optical output, passing the signals to my pre/pro and everything sounds great. It seems that the problem is somewhere in my analog output stage. Still have to find out if its the coupling cap removal or one of my opamp-on-adaptor things that's causing it.

 

[thoppa]

Hi,

Great - so it isn't the xo either then !

Then it might be oscillation, which would be the op amps and their 'load'.

Anyway, it's good you got the xo working !

 

[taisho_daniel]

Yeah, it's great to have the XO working.

Unfortunately I wasn't able to make a direct comparison before, but I think the XO upgrade made a difference in the digital out too. Like you said, one of the more cost effective upgrades for the ST.

 

[GWorlDofSPACE]

Thoppa I am very interested in your caps tweaks review. Would you please tell us what you discovered?

 

[thoppa]

Hi,

I replaced the ceramic caps - 2n2 I think - with 3n3 polyprop = Vishay MKP1837. This cut the bandwidth down (90Khz to 60Khz -3db, which is a drop of 0.2db at 20Khz and a drop of 2.5dB at 120Khz from standard) but I didn't hear any loss of treble or detail.

Before this, I hadn't enjoyed the LME49720HA - they sounded too harsh and hissy. After the cap swap, the aggressiveness was gone and the treble sounded more natural. I tried various op amps again and found the LME now sounded the best.

The change is subtle but it definitely gives a smoother and a more refined presentation of detail. A little sweeter and a little clearer too. But only a little !

It doesn't take long or cost much to do, so I definitely recommend it.

 

[GWorlDofSPACE]

Quote:

Originally Posted by thoppa /img/forum/go_quote.gif Hi, I replaced the ceramic caps - 2n2 I think - with 3n3 polyprop = Vishay MKP1837. This cut the bandwidth down but I didn't hear any loss of treble or detail. Before this, I hadn't enjoyed the LME49720HA - they sounded too harsh and hissy. After the cap swap, the aggressiveness was gone and the treble sounded more natural. I tried various op amps again and found the LME now sounded the best. The change is subtle but it definitely gives a smoother and a more refined presentation of detail. A little sweeter and a little clearer too. But only a little ! It doesn't take long or cost much to do, so I definitely recommend it.

Did you also changed the output caps or try them to bypass?

 

[thoppa]

Hi,

Yes, I changed the coupling caps to Blackgate N 33uF - this is more than enough for line level use to avoid phase changes etc, but would cause a bass roll-off if I used the RCA out to drive headphones. Actually, if I wasn't using the RCA out to drive a coupling-cap-free head amp, I'd just remove them completely as per Germanium's post and of course check the DC offset. Anything up to about 20mv is fine if going direct into cans, perhaps even as much as 50-100mV for some cans. Most gear has input coupling caps too....

 

[GWorlDofSPACE]

Quote:

Originally Posted by thoppa /img/forum/go_quote.gif Hi, Yes, I changed the coupling caps to Blackgate N 33uF - this is more than enough for line level use to avoid phase changes etc, but would cause a bass roll-off if I used the RCA out to drive headphones. Actually, if I wasn't using the RCA out to drive a coupling-cap-free head amp, I'd just remove them completely as per Germanium's post and of course check the DC offset. Anything up to about 20mv is fine if going direct into cans, perhaps even as much as 50-100mV for some cans. Most gear has input coupling caps too....

If you have an external amp, then a small mkp would also do great job here.

 

[thoppa]

Hi,

I tried this already - a 10nF MKP1837 first and a Mundorf 100nF second - but both gave noise not an improvement in sound. I have no idea why but I guess they picked up rf or emi or something....or maybe they just won't solder on well..... I also tried the Mundorfs in reverse just in case they had a shield.

The Blackgate N are pretty good so I don't mind. It's a real shame Rubycon have stopped producing Blackgates.

 

[GWorlDofSPACE]

Quote:

Originally Posted by thoppa /img/forum/go_quote.gif Hi, I tried this already - a 10nF MKP1837 first and a Mundorf 100nF second - but both gave noise not an improvement in sound. I have no idea why but I guess they picked up rf or emi or something....or maybe they just won't solder on well..... I also tried the Mundorfs in reverse just in case they had a shield. The Blackgate N are pretty good so I don't mind. It's a real shame Rubycon have stopped producing Blackgates.

yea blackgates! There is always a question of costs and interests.

 

[thoppa]

Hi,

I'm now thinking of using this card in a mini-itx music player so I can then fit audio-gd hdam. Have you tried these ? I reckon the Earth look the best choice but I wonder if 2x Earth in I/V and 1x Moon in the buffer would be better....I can't justify the price of the Bursons tbh.

I'm also thinking about upgrading the PSU to sigma11 and fit a 7912 on U34 on the board.

So maybe the card isn't finished after all.

 

[ROBSCIX]

There are a few guys around that have been using those HDAM's on the STX/ST.
They are nice, I tested them out on a few different sources a long while back.
The Earths make great I/V's. Personally I would choose another for the buffer but tastes vary.

 

[forDSD]

Hi everyone!

With great interest read this topic! I want to install on Xonar ST quality oscillator. In this model, the oscillator has a contact E/D. He managed with code... In our case - it is not necessary, of course!
This raises the question - what to do with the contact E/D? Just leave not connected? Please, help me understand, I will be very grateful!
The model of the oscillator - FXO-HC736R-24.576 http://www.farnell.com/datasheets/75456.pdf