I also have an "issue" in the low bass it seems. I bought two very high quality Viablue Y adapters, to be able to connect my active subwoofer on the single stereo output (my usual preamp has two outputs + a subwoofer output...)
Well I'm disappointed. Low bass seems weak. Normally I have to set the volume very low on the sub, otherwise it overpowers everything, it's a very potent Focal Electra SW900A... with the Yam preamp Have to set the sub way higher and it's still a bit anemic. I don't know if the Viable adapters are the cause (or if the output is unable to drive two devices? But being very low impedance at 47ohms, it should have no issue driving two pairs of cables and two amps) or if the preamp's caps are really dried out :-/
Can't be. There's no beer.
Cheers,
James
I also have an "issue" in the low bass it seems. I bought two very high quality Viablue Y adapters, to be able to connect my active subwoofer on the single stereo output (my usual preamp has two outputs + a subwoofer output...)
Well I'm disappointed. Low bass seems weak. Normally I have to set the volume very low on the sub, otherwise it overpowers everything, it's a very potent Focal Electra SW900A... with the Yam preamp Have to set the sub way higher and it's still a bit anemic. I don't know if the Viable adapters are the cause (or if the output is unable to drive two devices? But being very low impedance at 47ohms, it should have no issue driving two pairs of cables and two amps) or if the preamp's caps are really dried out :-/
Pretty sure those come in the "In case of emergency, break glass" type containers.
Have you been there long enough to remember "the Deutsche Mark" ? I think they went to the Euro in 1999.
I really love your posts!
Just an FYI if you ever want to seek a decent replacement for the JRC 2068's with something that is through-hole DIP package, that sounds good is the OP275 from AD. It doesn't quite match the performance of the OPA-1602 (which matches the current requirements, and where the OPA-1612 can draw too much current if the supply isn't capable) however, there isn't a real good choice to properly decouple SOIC on riser boards, so the advantages to be found in noise performance is actually lost. So i you are looking for something that sounds almost equal to the OPA-1602 in DIP then I can attest to the OP275, and it's performance is much more appealing than listening to the NJM2068.
The only one I know of that you can manually jump to any pin config, is to use something like this... (pin 1&9 on the SIP is the same V+, so you only need 8 pins)Interesting that you would bring this up. I just missed out on buying a Yamaha DVD-S2700 that I've been wanting to try out. It has OP275 op-amps in the analog section if I'm not mistaken, and I've read good things about that op-amp but have never tried one.
Is there such thing as a dip-8 to soic-9 adapter? I've tried to find one with no luck. I wanted to try out a LME49720 in the headphone section of the CX-1 (to replace the NJM2068SD [soic-9]) that I gave to my son and bought a Brown Dog dip-8/soic-8 adapter but no, that doesn't work.
Cheers,
James
The only one I know of that you can manually jump to any pin config, is to use something like this... (pin 1&9 on the SIP is the same V+, so you only need 8 pins)
http://anchor-electronics.com/product/capital-advanced-technologies-9082-surfboard/
Good luck making it the way you want it to be James!
Sometimes just talking it out helps to stir options. Keep us posted!Thank you!
Now I have to admit to having a defctive brain day yesterday. Because after looking again I saw that the headphone amp uses a NJM4556S-A and not a 2068. And looking at my archieved photos I see that I tried using the sip-8 adapter in pins 1-8 where it definetely won't work. But after looking over the data sheets using pins 2-9 it should work. I'll have to try again.
Cheers,
James
Let me make a suggestion, and that would be the OPA-1602. You'll derive the current you're looking for, can swing up to 40V, excellent THD+N, -130dB of channel separation, and is one of the best for phase stability over the entire audio spectrum as you will find. It sounds really good... Lots of commercial DAC's are now upgrading their headphone outputs to the OPA-1602. TEAC uses them exclusively now.Yes, discussion is always good. I'll try it again and see what happens. My only other concern is that the 4556 has 70mA of output and the 49720 only 26mA. So I hope that the LME49720 has enough ompfh do drive headphones all by itself. There doesn't appear to be any kind of further buffering or amplification after the op-amp.
Another option in the same family that I looked at is the LME49721. It doesn't have quite the same specs as the 49720 (but still quite good) but has an output rating of 100mA. But it shows an absolute max supply volt rating of 6v and it looks like there is about 16v on the supply rails, so I'm guessing that I can't use it.
Cheers,
James
Let me make a suggestion, and that would be the OPA-1602. You'll derive the current you're looking for, can swing up to 40V, excellent THD+N, -130dB of channel separation, and is one of the best for phase stability over the entire audio spectrum as you will find. It sounds really good... Lots of commercial DAC's are now upgrading their headphone outputs to the OPA-1602. TEAC uses them exclusively now.
http://www.ti.com/lit/ds/symlink/opa1604.pdf
http://audio.teac.com/news/display/951
The OPA-1612 is the very finest bi-polar op-amp I've used, and in the buffer stage, not much can touch it. It does take a little more supply current to run, and it's output current runs about 2/3rds of the OPA-1602. However, TI does have technical data for using the OPA-1612 for headphones, (which means they do recommend them for that usage) but just be aware of the output. If you find that the OPA-1612 doesn't give you the volume you may want depending on what you use for headphones, the OPA-1602 is your go to chip. But if I had no OPA-1602 on hand but I did have a OPA-1612, man, you bet I'd place it in there. There is light years of performance difference from the 4558. The only place I'd use a 4558, is for a motor controller or a meter driver.OK. That looks interesting. I'll add a couple to my next Mouser order. I do have a couple of OPA1612 that I bought based on another member's recommendation (I'm being stubbornly dumb and can't recall who at the moment. ?Beau Geste?). I haven't used them yet but based on your sig it looks like you have. Thoughts?
Cheers,
James
The OPA-1612 is the very finest bi-polar op-amp I've used, and in the buffer stage, not much can touch it. It does take a little more supply current to run, and it's output current runs about 2/3rds of the OPA-1602. However, TI does have technical data for using the OPA-1612 for headphones, (which means they do recommend them for that usage) but just be aware of the output. If you find that the OPA-1612 doesn't give you the volume you may want depending on what you use for headphones, the OPA-1602 is your go to chip. But if I had no OPA-1602 on hand but I did have a OPA-1612, man, you bet I'd place it in there. There is light years of performance difference from the 4558. The only place I'd use a 4558, is for a motor controller or a meter driver.
Just an aside, there are newer phones on the market that use the OPA-1612 for high performance DAC outputs for headphones, so if the headphones your son is using sounds okay attached to a mobile device, you can pretty much bet you'll love in in your usage.
OPA-2107 are DiFET. They aren't really intended for current audio usage. Instrumentation would be it's primary target. JFET is what many Engineer's opt for, and for that the OPA-1642 is a good choice. The 2107 does have fast settle time though, which is what you need for DAC buffer performance.Thank you! What are your thoughts on the OPA2107? I have some of them also. I use one 2107 and 2x LME49720 in my sound card and like the results a lot.
Cheers,
James
OPA-2107 are DiFET. They aren't really intended for current audio usage. Instrumentation would be it's primary target. JFET is what many Engineer's opt for, and for that the OPA-1642 is a good choice. The 2107 does have fast settle time though, which is what you need for DAC buffer performance.