[raider1v1]

i cant decide on what chip to get for the meta42 that i am getting built.

should i get the AD8620 or the AD843?

if you want to know anything else about the amp ask, but not to technical, i am still a super noob

 

[Budgie]

Suggestion- get a socket installed for the chip and buy both chips. Then you can easily swap them yourself. They are both popular chips, so it becomes a matter of opinion if you don't listen to them both yourself. Your builder can probably do that for you without any problems.

 

[earthling]

Quote:

Originally posted by Budgie Suggestion- get a socket installed for the chip and buy both chips. Then you can easily swap them yourself. They are both popular chips, so it becomes a matter of opinion if you don't listen to them both yourself. Your builder can probably do that for you without any problems.

The 843 is if I remember right a single channel amp meaning that you will need an adapter board to run it. Also, its going to suck a bit more power so you are into AC power territory especially with stacked output buffers.

 

[ServinginEcuador]

you'll have to use a Brown Dog adaptor to run two 843s in the same slot as a single 8620. You can compare some 8610s to the 843 since they are both single channel designs.

From what I heard, and many here agree, the 8610/20 is the best offerering that AD has. It is less harsh and sounds better than probably anything else they have to offer. I tried their 825 and compared it to the 843, and preferred the 825 myself.

 

[raider1v1]

hmmm

i was told this in a pm

Quote:

The AD843 and the AD8620 both have their own sound. I would characterize the 8620 as less "edgy" than the 843, or characterize the 843 as more "dynamic," so one is not necessarily better than the other. The 843 does need more than 9v though.

i do have an option for using the pactec case that uses 2 9v batteries

 

[morsel]

If you are using batteries, go with the AD8620. Consider the AD843 an option primarily for AC users, like the EL2002.

 

[Mystic]

I'm interested in hearing some opinions on the sonic differences between these two chips as well. I built a META42 with the 8620, dual 2001 buffers/channel and current source using 2 9V batteries. It sounds great to me and I'm very happy with it. I want to build another META42 for home use, AC only. I plan on using the 2002 buffers but am curious as to whether the 843 would offer better sound than the 8620. (I've never heard the 843.) One thing going for the 8620 in my case is that I have an extra one sitting here, I would have to purchase a pair of 843s.

 

[puppyslugg]

Quote:

Originally posted by raider1v1 i do have an option for using the pactec case that uses 2 9v batteries

FWIW: I would use 2x9v batteries regardless of what opamps you choose.
Quote:

Originally posted by Mystic I plan on using the 2002 buffers but am curious as to whether the 843 would offer better sound than the 8620. (I've never heard the 843.) One thing going for the 8620 in my case is that I have an extra one sitting here, I would have to purchase a pair of 843s.

Geom_tol has ad843's for $5.50 ea. Reasonable way to try them out. Nice guy, too. BTW: The ad843 is one of ppl's favorite.

 

[slindeman]

It's not just the voltage that precludes using the AD843 portably, but the fact it draws 4x the current compared to the AD8610. I would go so far as to say don't use the AD843 portably unless you'll be using AA or AAA batteries, preferrably rechargeable. That is, unless you don't mind buying lots of 9V batteries, or charging them after every 6 hours of use.

 

[slindeman]

Quote:

I tried their 825 and compared it to the 843, and preferred the 825 myself.

Did you compare them in a headphone amp or in the D500SE you had? If it was the D500SE I wouldn't doubt the AD843 performed poorly since the power supply is +-5V and the AD843 would not like that at all. The AD825 is spec'd fine for +-5V.

 

[ServinginEcuador]

Quote:

Originally posted by slindeman Did you compare them in a headphone amp or in the D500SE you had? If it was the D500SE I wouldn't doubt the AD843 performed poorly since the power supply is +-5V and the AD843 would not like that at all. The AD825 is spec'd fine for +-5V.

Hmmm, I don't know if that was a problem or not. It was in the D500SE, but that chip didn't seem to have problems when listening to it. OTOH, the OPA627 sounded horrible and clipped whenever a loud piece of music suddenly hit.

All in all, the 843 didn't sound harsh, and neither did the 825, but then again, we're talking about a D500SE, so it might not have made any difference with the low voltage anyway. I guess they did sound alike to me, so it might have performed better with a higher supply voltage.

 

[raider1v1]

so basicaly use the ad8620 because the batteries will be drained to fast and i would hate to keep changing them

 

[Budgie]

I am finally listening to the 8610's that puppyslug sent me and I have to say, this is an excellent sounding chip and I do not think you would be going wrong in using it. This is the first chip I have listened to that does not give up harmonic richness in favor of a sterile, but fast sound. Good transients, but nice warmth.

edit- using them as the output stage in my cdp, resistor biased into class A (3 ma) and +/- 15 volt rails. 2 volts higher then spec!

 

[tangent]

Quote:

[I tried the AD843] in the D500SE, but that chip didn't seem to have problems when listening to it.

The 843 will not be happy with 10V. It may work without clipping, especially running into the high-impedance input of a power amp, but it won't be happy. Its minimum specified voltage is 9V, at which level you can get 1V RMS at the output, which is barely line level. Going up to 10V for the supply will only get you a fraction of a volt RMS more at the output. I personally never run this chip at less than 12V, and to get 2V RMS at the output you'd need more like a 14V supply.

Quote:

so basicaly use the ad8620 because the batteries will be drained to fast and i would hate to keep changing them

For 9V batteries, yes, avoid the AD843 unless your goal is the best possible sound at any cost. And even then, remember that some people say the AD8620 sounds better than the AD843. I'm not one of them, but hey, people hear things differently. Even if, to you, the AD8620 is second-best, it's still a damn good chip. For portable use, it's the best, in my book. For my own amps, I only use the AD843 in wall-powered ones.