[DavidMahler]

I bought a Larocca PRII and I love the sound. However as of recent I began using it with my iPod.....and whole different selection of iPods. There is a hum (high pitched hum) whenever connected to my iPod. I sent the amp off to a very well respected audio engineer whom is popular on head-fi. After using it with his iPod and opening it and spending numerous hours observing the interior he concurred that there is nothing wrong with Larocca PRII, that it is a design flaw which makes the Larocca PRII and the iPod incompatible.

I wanted to ask this question.....if you own the Larocca PRII MKii, do you have this same high pitched hum. If you sincerely do not have this compatibility issue I may be willing to buy your amp or trade yours for mine with an additional sum.

-Dave

 

[deathg0d]

i have a pr ii mk2 but i do not get the hum unless i plug in the power supply and when i touch the knobs with my fingers.

not sure what setup you have thus it very difficult to conclude that there is a design flaw in pr ii

 

[DavidMahler]

The hum is battery operated amp with ipod through any cable.

 

[PhaedrusX]

considering that this is a portable amp designed to be used with DAPs, i doubt there is a "design flaw" that makes it unsuited for use with an iPod.

Phil Larrocco (ppl) is a member here. you should probably try sending him a PM and asking him what the problem might be.

 

[mshimao]

I have one. When I connect the input cable to the amp without the iPod attached, there is a hum. However, when I attach the iPod, the hum goes away. Hope this makes sense. The hum I hear, by the way, is more of a mid-pitched hum; not a high-pitched hum.

The sound is great, isn't it!

 

[DavidMahler]

NOTE: I left out something very important. The hum is only audible with low impedance IEMs. Those of you that own the amp, please check this out....look for a very high pitched hum using the iPod.

Thanks

 

[mshimao]

No high pitched hum using Shure e3c.

 

[ppl]

I would check the grounds on the RCA jacks the PC Board to case and Volume control to case these are known Larry issues with everything he made. Sorry, for your Inconvenience with your PR II However, my time is limited and many of Larry’s Builds have issues. I would think a DIY type should be able to troubleshoot and service the amp. In addition your amp should not be humming or buzzing connected to an I pod unless the ground is less than clean then you will get the Digital noise that is not all that well filtered in the 1st place from driving the Ground with this dirty signal and amplifying it. Check RCA to case and PCB ground 1st may be oxidized (Pressure fit) since you have had the amp 1 year (Wow Larry still selling PR-II”s then) I suspect its quality has deteriorated.
Again I want to Stress that Larocco Audio products were my designs that Larry built and since I have not had any contact what so ever with Larry in several Years I assume any of my designs he sold were so far removed from there original design that it is questionable they could still be considered my designs as opposed to what they became and that was an abomination of an Amplifier based upon my Design but substantially changed from it in the interest of cost and ego.

 

[DavidMahler]

After much testing I discovered that this hum is started by touching the ipod screen while the ipod is connected to the amp. You must use IEMs in order to hear this......can anyone else confirm that theirs does this too?