[aos]

Has anyone experimented with battery voltage and AD8610? When I and ppl looked at datasheets way back, we guessed about 6V (+-3V) would be lower boundary. I used only 2x9V so far and really noticed catastrophic change in sound when batteries were quite dead, which was usually less than those 6V when you add them together. Did anyone do listening tests with varying voltages and reached any conclusions? I plan to run from 8AA batteries but I'm wondering if 7.2V Li-Ion would still sound good and I'm sick already of doing A-B tests and trying hard to hear a difference...

 

[puppyslugg]

Hi aos,

On my JMT-CHA47, I swapped the opa2132(?) with the AD8610, using a single 9v baterry. Recently, I tried 2-9v in series and thought the sound was airier; better sense of depth; there was a greater sense of ease to the music; and maybe overall it was smoother. Which made me think: Do the ad8610 like more voltage? This was percieved using low impedence Senn.280 phones. A single 9v or 2 in parallel will give about 4.5v which is not that far from the 3v limits. Not a whole lot of room. I also had tried 2-9v in parallel and I preferred the 2-9v in series. Will also be looking into a 4-9v in series/parallel config.

 

[KurtW]

I breadboarded the Meta42 (using single 2001s for the power supply and output buffers) circuit using the AD8620, and powered it from a variable outboard supply. I was encouraged by the graph in the data sheet showing supply current vs supply voltage, as it gets pretty linear after +/- 3.5 volts. I found that it ran down to just under 5 volts total before it totally crapped out. Using a Panasonic SX510 cdp and Grado SR80s, I didn't notice much difference in sound when I varied the supply from 9 volts to 24 volts...it sounded quite impressive, by the way. Perhaps this test is limited by the cdp. Based on this, I planning to build it into a one 9v battery case, and use the Plainview 9.6v NiMH battery. The Plainview fully charged actually puts out over 10 volts. Most rechargable 9v batteries don't ever make it to 9v.

 

[ppl]

Radio Shacks 9 Volt NI-MH batteries put out 10.45 volts when fully charged but go down to 9.8 if left standing after Fully Charged for a day and stay at that level for quite a while. BTW the Plainview battery mentioned is about the Best you can get. This battery is intended for Medical uses.

Regarding the sonic change of the 8610 and 8620 at lower supply voltages i havent tried this test yet but unlike other Opamps with the Exception of the AD-823 i could not Predict when the Batteries were in Need of recharge Prior to them Going dead the Music plays and sounded good untill Music no more because of Dead batteries. However this is at my normal listening level that is less than 1 Volt Peak. and my MDR-V6's. Other opamps will start to sound real bad just prior to the batteries going dead.

I think apart of the sonic change at low voltages with the 8610 & 8620's is the fact that all Audio Amps sound better at Higer rail voltages as more Headroom is available and the signal is not as close to the rails. This is also IMHO part of the reason tubes sound so dynamic is thay operate at High rail Voltages.

 

[aos]

So I should have no problem using 8AA's, having 11-12V total voltage.

I know EXACTLY what you're talking about ppl. Here I sit listening to Harry Potter soundtrack and suddenly I start hearing some noise, crackle, and within 30 seconds the sound is gone. Happens all the time. It's not very gradual at all.

So, I might be fine even with one Li-Ion at 7.2V or so? Those batteries are so expensive that I can't justify using two... if I ever even buy one. Not to mention charger that costs just as much.

 

[ppl]

aos> I would think so providing your listening levels are not great, However i like to have Headroom for Dynamics so i always use two 9 volts or 16 Cell batt. Packs. Maby i should take out one of the 9volts in my pocket amp and see if the sound changes, this would be easy to do just jumper across the contacts on the removed battery's Holder. yes i use those cool 9 volt plastic Keystone Holders available at digikey thay hold the battery in place under all conditions but somewhat hard to replace batteries.

 

[jarthel]

Can these opamps be used in +/-15V? Thanks

Jayel

ps. I know the spec says +/-13V but some of you might have tried higher voltages.

 

[ppl]

I have not tried it but do a search because another user did in his Sony CD player and stated it worked for a while then quit. so i would not try it.

 

[aos]

I wouldn't use 16 cells. If you put regular batteries by mistake you're going to fry your chips! It will be more than 24V by quite a margin. And I wouldn't trust Analog's maximum ratings. Their voltage regulators say they should work up to 12V and have max rating of 15, but 8AA batteries, at a bit over 13V, have destroyed one of them in less than a minute if not instantenously.

 

[ppl]

On most data sheets a statement close to the following will be included " Maximum ratings are for stress test only and Operation at these max. ratings will result in damage and or device falure. operation at these max ratings is not implied and any operation beyond the those stated in the operational section will result in damage"

 

[aos]

Yeah, if you run it for hours. If you run it for seconds and not even at the edge of test limit and it dies, I'd say a limits in datasheet are optimistic. Very optimistic.

 

[ppl]

I tend to agree on that as this opamp starts to sound strange above +/- 10.5 Volts. and so dose the AD-8065. However that is the good thing about these opamps is that unlike other High quality Opamps these work great on a pair of 9 volts. somthing the OPA-627 will not do and sound it's best.

 

[finleyville]

Is +/- 9VDC adaquete enough to power Senn's HD600 to their fullest?

 

[ppl]

Yes two series connected 9 volts for 18 volts

 

[morsel]

Sounds strange how, PPL? This is the first I have heard anyone say the AD8610 sounds less than perfect at ±12V.