[trybeingarun]

Is LME49990 compatible with the new HPA-3U (apparently stock is LME49860)? I know nothing about op-amps, but am wondering if it's worth taking a shot.

 

[Socratease]

  Is LME49990 compatible with the new HPA-3U (apparently stock is LME49860)? I know nothing about op-amps, but am wondering if it's worth taking a shot.

Looks like the LME49990 may no longer be in production, I can't find it on TI's product web site.
 
They're both in the same family of HiFi op-amps.  Small differences in performance specs between them, the 49990 has better noise and distortion figures, but the 49860 can handle higher voltages (up to +/-22V).  Unless you're feeling adventurous and don't mind the cost of the experiment, I'd leave the stock one alone.

 

[Praeceps]

The LME49990 is working great at the moment thanks.
I'm thinking of whether to buy some HD598 or at least test them. I've heard it can be more suitable for gaming and watching movies as they have a better soundstage.  (I've been using the HD650 for everything on the PC so far)
Is the RCA out around the same as the headphone out? Does the volume control on the amp control the RCA out too? I'm thinking of getting a female 3.5mm to RCA for the HD598 to connect to the RCA out just out of convenience. Or would it just be best to swap headphones on the headphone connection?

 

[Pharmaboy]

  The LME49990 is working great at the moment thanks.
I'm thinking of whether to buy some HD598 or at least test them. I've heard it can be more suitable for gaming and watching movies as they have a better soundstage.  (I've been using the HD650 for everything on the PC so far)
Is the RCA out around the same as the headphone out? Does the volume control on the amp control the RCA out too? I'm thinking of getting a female 3.5mm to RCA for the HD598 to connect to the RCA out just out of convenience. Or would it just be best to swap headphones on the headphone connection?

 
Assuming you have the HPA-1 (not one of the later M Stage iterations), I can answer your questions:

1. The RCA out on back panel is intended for connection to powered speakers, an external amp, etc. It does convey the same information as the TRS headphone output--both are controlled by the volume pot.
2. The volume pot does control both the TRS headphone ouput and RCA L+R output pair. I used my HPA-1 as a headphone amp/preamp (driving powered speakers + sub) for many months...it's very good as a preamp.
3. Re connecting a headphone to the RCA L+R output pair, I have no idea if that would work. I would be leery of trying that, since it's possible the line-level RCA out has higher voltage than the headphone output (ie, both outputs are controlled by volume pot, but RCA out may have higher level to begin with). I'm just speculating.
4. If it were me, I'd just just swap headphones on the headphone output.

 
Re HD598, I've never heard it, but I know 1 Head-Fi'er who uses it for gaming & really loves it.

 

[Praeceps]

Yeah it's the HPA-1.
Okay yeah I'll just swap on the headphone output. Thanks.
 
I have just noticed the Massdrop Senn PC37X. I don't think it's worth it now though as it's a long waiting list. I just missed a drop on it so the next drop won't be around until July. It's just as well though as the build quality is a bit lower the HD598 plus I already have a mic setup anyways. (Samson go mic attached to a flexible arm phone holder 

)
 
Edit: Another thought. What are the K702 like compared to the HD598s? I have heard the K702 is quite good for gaming.

 

[trybeingarun]

  Yeah it's the HPA-1.
Okay yeah I'll just swap on the headphone output. Thanks.
 
I have just noticed the Massdrop Senn PC37X. I don't think it's worth it now though as it's a long waiting list. I just missed a drop on it so the next drop won't be around until July. It's just as well though as the build quality is a bit lower the HD598 plus I already have a mic setup anyways. (Samson go mic attached to a flexible arm phone holder 

)
 
Edit: Another thought. What are the K702 like compared to the HD598s? I have heard the K702 is quite good for gaming.

I have K7XX and hd598s. I don't play games but I use them with movies and songs. To me K7XX sounds much better than HD598se in terms of definition & overall sound quality. To me k7xx is an obvious pick. If K702 is anywhere close to K7xx it's better to pick K702

 

[Praeceps]

  I have K7XX and hd598s. I don't play games but I use them with movies and songs. To me K7XX sounds much better than HD598se in terms of definition & overall sound quality. To me k7xx is an obvious pick. If K702 is anywhere close to K7xx it's better to pick K702

Are the K7XXs just as comfortable as the hd598s? I know the hd598s will be comfortable seeing as I have no problems with the HD650 but I have heard before that the K702s can be hit and miss on comfort for some, especially for long sessions. But then again the K7XX has better ear foam so I guess that can make a difference.

 

[Mad Max]

K70x headband bumps are what put some people off.
Luckily for me, my K701's bumps don't bother me.  I don't know why AKG even bothered to design the headband that way, the bumps are not soft enough for best comfort, I think.

 

[trybeingarun]

  Are the K7XXs just as comfortable as the hd598s? I know the hd598s will be comfortable seeing as I have no problems with the HD650 but I have heard before that the K702s can be hit and miss on comfort for some, especially for long sessions. But then again the K7XX has better ear foam so I guess that can make a difference.

K7xx earcups are huge & but a tiny bit shallow than hd598 so the top of my ear brushes against the driver, just barely though. To me both are equally comfortable and I slightly prefer k7xx over hd598. If you also have hd650 then you should definitely look into k7xx as they have different sound signatures. HD598 & 650 sound similar and you would probably never end up using 598s that much.

 

[Praeceps]

  K7xx earcups are huge & but a tiny bit shallow than hd598 so the top of my ear brushes against the driver, just barely though. To me both are equally comfortable and I slightly prefer k7xx over hd598. If you also have hd650 then you should definitely look into k7xx as they have different sound signatures. HD598 & 650 sound similar and you would probably never end up using 598s that much.

Okay cheers problem is that I don't know when the next massdrop will be. Hopefully they will do it soon. I've seen rumours that the red one might come up soon.

 

[leeperry]

  LME49990 is working great

 
Now that everyone's taken his 49990 pill, get ready to roll power cables oh yes......lipstick on a pig yadayada

 

[rikk009]

   
Now that everyone's taken his 49990 pill, get ready to roll power cables oh yes......lipstick on a pig yadayada

Why not burson V5? I see everyone buying cheaper units like xduoo XD-05 and replacing Muses opamp with v5i and declaring it the best. 

 

[mickerru]

Anyone used the mojo to feed the quattro amp to the hd800. Contemplating on getting the quattro as my first amp. Thanks

 

[mickerru]

Anyone who can advice which to buy. The quattro amp or mstage 3b to drive the hd800. I think both are good. Im just checking if the 3b is better than the quattro. Thanks

 

[leeperry]

As much as rolling power cables helps, at the end of the day it's still using a cheapo IEC socket, most likely steel wires going to that molex connector, low grade pins going to the PCB and a hair-thin cheapo fuse so I think it would require some major modding to make a good power cable truly shine and I'm not keen on messing with such high voltage....OTOH an audio-grade fuse costs $3 and bypassing the DC filtering caps is very easy to do and provides a tremendous SQ improvement huh!

Rolling the HO socket would be great too, will be looking into that