[cubusmybro]

I am trying to remove the volume knob so I can put a faceplate on my O2. If anyone could help I would greatly appreciate it because I have no idea. Thanks

 

[proton007]

I am trying to remove the volume knob so I can put a faceplate on my O2. If anyone could help I would greatly appreciate it because I have no idea. Thanks

afaik you should be able to pull it out.

 

[DairyProduce]

Quote:

I am trying to remove the volume knob so I can put a faceplate on my O2. If anyone could help I would greatly appreciate it because I have no idea.

Thanks

 
Hey!
 
I just got my O2 amp two weeks ago. Is there any reason you want to remove the volume knob? (replacing a broken one?) Or is it just for cosmetic purposes?

 

[HamilcarBarca]

Quote:

Quote:

I am trying to remove the volume knob so I can put a faceplate on my O2. If anyone could help I would greatly appreciate it because I have no idea.

Thanks

 
Hey!
 
I just got my O2 amp two weeks ago. Is there any reason you want to remove the volume knob? (replacing a broken one?) Or is it just for cosmetic purposes?

 
The knob must be removed to add or remove the faceplate.
 
I'm not the OP, but I'd like to replace my brushed aluminum faceplate with the black one from Mayflower Electronics. Would you check yours to see if the knob is held in place with a tiny set screw? Mine's at work.

 

[mikeaj]

Seems like it's to be able to "put a faceplate on".  You can't remove or insert a faceplate unless the knob is removed.  If you're worrying about the part breaking, underneath the knob is a high-quality ALPS potentiometer of metal construction.  It's not a tank, but it's not some cheap junk volume control that's going to break (or have mediocre channel balance)
 
As mentioned earlier, the knob should just slide off with a strong tug.  There's no screw.  Easiest way to remove may be just to unscrew the faceplate and pull on that, which should pop it off.

 

[DairyProduce]

Quote:

 
The knob must be removed to add or remove the faceplate.
 
I'm not the OP, but I'd like to replace my brushed aluminum faceplate with the black one from Mayflower Electronics. Would you check yours to see if the knob is held in place with a tiny set screw? Mine's at work.

 
Sorry, I don't have any screwdrivers near me (had to borrow my friend's last time to open it). 
Maybe you can check some photos from jdslabs?

 

[miceblue]

Quote:

I am trying to remove the volume knob so I can put a faceplate on my O2. If anyone could help I would greatly appreciate it because I have no idea.

Thanks

You need a hex/Allen key to loosen the hex screw on the volume knob. Once you get that loosened, you can just pull the knob off without a problem.
 
Yes there is a screw. It's pretty standard for all potentiometer volume knobs or else it wouldn't securely stay in place.

 

 

 
 
 
And yes you need to remove the volume knob to take the faceplate off.

 

[HamilcarBarca]

Quote:

As mentioned earlier, the knob should just slide off with a strong tug.  There's no screw.  Easiest way to remove may be just to unscrew the faceplate and pull on that, which should pop it off.

 

Originally Posted by miceblue /img/forum/go_quote.gif
 
You need a hex/Allen key to loosen the hex screw on the volume knob. Once you get that loosened, you can just pull the knob off without a problem.
 
Yes there is a screw. It's pretty standard for all potentiometer volume knobs or else it wouldn't securely stay in place.
 

Spoiler: O2%20Volume%20Knob%20closeup

 
Thank you both for the replies. While looking at the closeup, I realized that the volume knob on an Objective2 amp is chosen by the manufacturer (distributor.) Mine is from JDS Labs and matches the picture above.
 
 

Originally Posted by miceblue /img/forum/go_quote.gif
 
And yes you need to remove the volume knob to take the faceplate off.

 
At least I got one thing right!

 

[agdr]

Thank you for the analysis. I'm not an EE, but I'll read it and do my best to understand.

What it all boils down to is a 14Vac - 16Vac transformer with a 400mA or greater secondary rating (like the WAU16-400) means not having to know any tech details about the whole thing. It will just work, with the one exception of using a low impedance headphone that is also low sensitivity, that might pull more than 56mA per channel. Then use a 14Vac - 16Vac 1000mA unit, like the WAU16-1000 which is only $0.25 USD more anyway at Mouser ($11.50 USD vs. $11.75). Might as well just get the 1000mA unit if there is plug space - it is about 25% larger physically.

To make a 12Vac secondary work with lower line voltage, and/or with only a 200mA current rating, one would need to know the pile of details I posted to be sure it would work for the specific situation. I just updated my post to note that if a person is sure they have high(er) line voltage, like 120Vac - 130Vac in the USA, and is known to be stable plus or minus a few volts over the course of the day, then a "12Vac" secondary will work since it will really be running at 13Vac or more under load. "Voldemort" may have been figuring that into the original specification since much of the line voltage in the US is around 120Vac these days (mine is 121Vac at the moment and is usually +/-1Vac).

So in that case just "fixing" the secondary current problem (increasing it) is all that is needed, say with a 12Vac 1000mA WAU12-1000 unit (Mouser part #553-WAU12-1000). The voltage regulators in the O2 will run cooler with the 12Vac 1000mA unit than with 14Vac or 16Vac, so if someone is certain they will always have higher AC line voltage that would be a good way to go.

Proton007: Interesting that "Voldemort" suggested the 16Vac! I may have had an effect, lol. :normal_smile :

 

[Dutchi MerenGue]

Quote:

What it all boils down to is a 14Vac - 16Vac transformer with a 400mA or greater secondary rating (like the WAU16-400) means not having to know any tech details about the whole thing. It will just work, with the one exception of using a low impedance headphone that is also low sensitivity, that might pull more than 56mA per channel. Then use a 14Vac - 16Vac 1000mA unit, like the WAU16-1000 which is only $0.25 USD more anyway at Mouser ($11.50 USD vs. $11.75). Might as well just get the 1000mA unit if there is plug space - it is about 25% larger physically.
To make a 12Vac secondary work with lower line voltage, and/or with only a 200mA current rating, one would need to know the pile of details I posted to be sure it would work for the specific situation. I just updated my post to note that if a person is sure they have high(er) line voltage, like 120Vac - 130Vac in the USA, and is known to be stable plus or minus a few volts over the course of the day, then a "12Vac" secondary will work since it will really be running at 13Vac or more under load. "Voldemort" may have been figuring that into the original specification since much of the line voltage in the US is around 120Vac these days (mine is 121Vac at the moment and is usually +/-1Vac).
So in that case just "fixing" the secondary current problem (increasing it) is all that is needed, say with a 12Vac 1000mA WAU12-1000 unit (Mouser part #553-WAU12-1000). The voltage regulators in the O2 will run cooler with the 12Vac 1000mA unit than with 14Vac or 16Vac, so if someone is certain they will always have higher AC line voltage that would be a good way to go.
Proton007: Interesting that "Voldemort" suggested the 16Vac! I may have had an effect, lol.

 
lol my head hurts reading that, can you just tell me which one would optimally power my o2 when it arrives without burning out or better still, not burning down my house?

 

[mikeaj]

Quote:

lol my head hurts reading that, can you just tell me which one would optimally power my o2 when it arrives without burning out or better still, not burning down my house?

 
Try rereading the first sentence, unless that was actually too complicated, or...?
 
For most people and usage, WAU12-200 is probably okay.  There can be problems, particularly if you're using the batteries, and some other factors.
 
If you don't want to figure anything out, pay $5.45 more and get the WAU16-1000:
here

 

[Dutchi MerenGue]

Quote:

 
Try rereading the first sentence, unless that was actually too complicated, or...?
 
For most people and usage, WAU12-200 is probably okay.  There can be problems, particularly if you're using the batteries, and some other factors.
 
If you don't want to figure anything out, pay $5.45 more and get the WAU16-1000:
here

lol my bad, i had just finished overeating kfc and was lying back struggling to read your post while at the same time fighting off drowsiness, thanks for the link tho

 

[HamilcarBarca]

Quote:

Quote:

lol my head hurts reading that, can you just tell me which one would optimally power my o2 when it arrives without burning out or better still, not burning down my house?

 
Try rereading the first sentence, unless that was actually too complicated, or...?
 
For most people and usage, WAU12-200 is probably okay.  There can be problems, particularly if you're using the batteries, and some other factors.
 
If you don't want to figure anything out, pay $5.45 more and get the WAU16-1000:
here

 
More good stuff which I've finally gotten around to reading. Thanks.
 
If I can impose on you again, I have three questions. Both the Late, Lamented Lord and you mentioned low-impedance, low-sensitivity headphones. AKG rates their K701 at 62Ohms (and 105dB which seems efficient to me.) HiFiMan rates their HE-500 at 38Ohms (and 89dB.) 
 

1. Do these represent limiting cases for the O2's design?
2. Does the Beyerdynamic DT 990 Premium, rated at 32 Ohms (and 96dB), qualify as inefficient?
3. Is the risk of using an inadequate but "approved" transformer on a non-battery-powered O2 setup confined to failure of the transformer itself?

 
The conclusion, in any case, was easy for me. I work in an office which for years has had insufficient power; in Wintertime; we've been known to trip the breakers without knowing why.
 
The WAU16-1000 is currently $11 from Mouser. I ordered one this evening and paid $7 for USPS Priority Mail postage.

 

[Uberbob102000]

If I can impose on you again, I have three questions. Both the Late, Lamented Lord and you mentioned low-impedance, low-sensitivity headphones. AKG rates their K701 at 62Ohms (and 105dB which seems efficient to me.) HiFiMan rates their HE-500 at 38Ohms (and 89dB.) 

If I recall correctly the AKG rating you listed is dB SPL/ V while the HE-500 rating is 89 dB/mW. The AKG is ~ 94 dB/mW but I'd double check that as it's off the top of my head.

 

[Bojamijams]

Just ordered one from JDS with 1x / 6.5x setup. Going to try it with my turntable and as a dac+amp from laptop. With JH|13's and DT880 600ohm.  pretty diverse. looking forward to it.