Seems like classic ground loop. How far is the amplifier from the DAC?I noticed that there's a lot of hum when nothing is played and amplifier volume is above 10 o'clock, but it stops when you remove the usb cable, maybe is not audible with music playing. I tried different cables but is the same.
6cm!? It's actually sitting on the blu ray and the blu ray on the amplifier.Seems like classic ground loop. How far is the amplifier from the DAC?
Hello,Update: I ended up using an OPA2227 in this box. Similar mids to the LM833 but better highs. Also was able to verify on oscilloscope that the circuit surrounding the op amp allows use of uncompensated duals like the OPA2228 (which although nothing more than an uncompensated 2227, has a different sound).
Thanks, Amirm. I look forward to your test and findings.Welcome to the forum Rob. I plan to test different opamps in d10.
I have a question about op amps. I would like to replace them in both DACs. I have ordered some LME49860 to try. I see your suggestion of OPA2228 or OPA2227. Would they also work for the D10 in place of the OPA2134?
On another note, I also would like to do an op amp upgrade on my TPA3250 amp which uses dual NE5532s. Do you have any recommendations?
In general OPA2227, LME 49720 will usually work in place of OPA2134 and NE 5532, but the 5532 might not work in some circuits in place of the others. I haven't used the LME49860 so my only comment on it is that it specs as if its a 44V version of the LME49720...the biggest downside being it looks like it is not available in a PDIP package which means it has to be soldered to a SOIC to PDIP adapter for D30 duty. I would shy away from the 2228 in the D30 since even though I o-scoped it as stable, the data sheet and the traced circuit indicate it shouldn't be. Another interesting tidbit is the 2228 dual is stable at a gain of about 3 or so (at least the ones I have are) on the test bench while the 228 singles I have are not...they are only stable at the spec value of gain>= 5. The x228 is a great sounding piece for higher gain circuits though IMO...I use them in my monitor system preamp along with LME49720.
As others have said, rolling opamps has its risks...lol, I thought I bricked a brand new D30 because when I was testing it outside of its case I laid the naked board on a piece of plastic for insulation while hooked up so I could quickly swap opamps, but failed to notice the allen wrench on the plastic, which shorted the naked board and no more sound. Turns out it only fried one of the diodes in the negative voltage converter section so no big deal and had going again in thirty minutes, but I was thinking $ down the drain for a while there. As for SQ gains, its more like SQ differences IMO. The 2134 that comes in it is a great sounding piece IMO and I've used plenty of them in other equipment. I just didn't like the stock sound of the D30 through my particular amp and monitors, and fortunately doing the swap was enough to make my ears happy. And I very well might like the stock D30 fine through another system. And for a bit of perspective, my musician wife is asking "what difference??" so the SQ differences are subtle.
I actually found a pdip version of the LME49860 on eBay.
is the op amp you swapped in the D30 socketed or did you have to de-solder/re-solder the new one?
I hope it really is authentic as advertised. The TI datasheet doesn't show it available, but maybe they used to offer it and the ones on ebay are older. A lot of people claim to hear a difference between the 4562 and 49720 (and apparently 49860). Personally, I could discern between the first two. They are both great sounding pieces imo and I have both in vsirous pieces of equipment.
Unfortunately no. You'll have to socket it if you want to comapre them. If you don't mind trashing the 2134 the job is much easier when you clip the pins as close to the plastic body as possible. That way you're desoldering a single pin/hole at a time and you can just grab the pin on one side while you place the iron on the other. The pin holes are very small on this board so removing the opamp intact is more of a challenge. I managed it but was really temped to clip it since I have a few extra of thos anyway...
Impressions are initial. Subjectively does the Topping D30 sound like ass; and how does it compare to the S19? The S19 is a poser, a wannabe. The student artist who does have great ideas, but cannot draw, cannot execute. The S19 is an embarrassment. In contrast, the D30 does not aspire to anything, nor does it execute anything well. It is plain and it sucks. The stage flat, closed in, and everything sounds like it is rendered at the same volume. The only good thing is that it doesn't have that nasty timbre and artificial detail from the Sabre implementations of the past. It does measure pretty good though like any other decent DAC. I've provided Schiit Modi 2U (older version) for comparison. And no, the Schiit DACs do not measure like shit, at least in competent hands they do not.
P.S. I just realized not Sabre but CS4398 chip for the Topping D30. Makes total sense - didn't sound like Sabre to me. Cirrus chips sound boring. You guys can go back years and find a post on HF or CS where I listed a bunch of chips and described their sound. Yes, a big part of how DACs sound is actually based on the chips. There is a line of thought from some people who believe it's the implementation that matters most. This is only true to an extent. All the other parts (power supply, receiver, clock, etc.) matter, but they simply only help realize the sound of the digital to analog chip (or discrete ladder). A Jeep is still going to feel like a Jeep, whether you throw on it a Hemi engine, knobby tires, raised suspension, heavier duty suspension, etc.
Looks like the "other" site is trying to negate your findings even comparing it to the Modi2U. http://www.superbestaudiofriends.or...opping-d30-dac-measurements.6270/#post-205709
Pretty sad.
Also this crap: http://www.superbestaudiofriends.org/index.php?members/purr1n.3/#profile-post-11929