Raven Labs PHA-1 - questions

placeboe · #1 08-22-2010, 11:35 PM

I know more than a few of you out there have one of these in your gear-stash. You may have had a similar problem, or could point me to someone with a schematic or who could repair.

After searching all the forums and reading the reviews on the PHA-1, it had all the features I wanted for home practice along with .mp3 - and I could run my Sennheiser HD650's on it also. Finally found one online, and received it. Bass sounds great thru it - but can't get the Mix-In to work. Don't know if I have a cabling problem or PHA-1 problem.

Have tried multiple cable configurations, different sources (both stereo and mono) with same results.

I can only hear the line in when the source component is almost maxxed out on volume - and only then do I hear it very faintly thru the headphones. The front panel MixL and MixR pots have no effect on this level. The stereo/mono switch apparently works, because you can hear that when switched.

Thanks for any response in advance, placeboe.

wave rider · #2 08-23-2010, 02:12 AM

I wonder if it is something about the connection between mp3 player and PHA-1. The manual speaks of a cable: "Entirely hand made in California, the PHA-1 comes with a CD or casette deck patch cord and three year limited warranty. "

I just use a 1/4" stereo plug adapter for an 1/8" mini-plug from my CD player into the mixin input. It does seem like only one of the volumes works for the CD when I play it through my amp...

Don't know if the manual will help but here you go:
http://web.archive.org/web/200707152...a1/pha1om.html

Product page:
http://web.archive.org/web/200707152...pha1/pha1.html

Main site frameset page:
http://web.archive.org/web/200805271...mainframe.html

The Wayback machine is a very cool thing!

=wr=

Munjibunga · #3 08-23-2010, 09:34 AM

You might try cleaning the input jack for "Mix In". Put some deoxit on a plug and insert and remove it a number of times. I use a .22 caliber bore brush for this. Also check your cable. I made my own, and it's just a TRS ¼-inch on one end and a TRS 3.5 mm on the other. If neither of those work, it may need repair.

tiz_1 · #4 08-23-2010, 12:32 PM

I just use a simple stereo 1/8" to stereo 1/4" cable from radio shack. Works between headphone out of cassette deck, mp3 player, or my dell pc headphone out. Plenty of level.

You do know you have to turn up the Mix L / Mix R level controls, right? If not, try running those about halfway up to full and then adjust the source volume.

Mine will easily blow my ears off.

--Kevin

Jeff Scott · #5 08-23-2010, 04:34 PM

Check the cable going in and the output of your source device. I just tried running one of my passive basses into the Mix In on mine and it even has a fairly healthy output from the bass (to get output into both cans of your headphones you will have to set the switch to Mono).

placeboe · #6 08-23-2010, 05:01 PM

Hello all, thank you for the responses. It sounds like I may have a problem internal to the unit. I've tried everything suggested, except the .22 cal bore brush (which I might try tonite).

Here's the cable / source combinations I've tried:
- Sansa View .mp3 3.5mm TRS out
-using 3.5mm TRS male to male cable, with 3.5mm to 1/4 TRS adapter on the PHA-1 end.

- Samsung .mp3 3.5mm TRS out
- using same cable as above.

- JVC home stereo amplifier - headphone out 1/4" TRS jack
- using same cable as above, except TWO adapters.
- mono TS instrument cable.

- JVC Component CD deck - headphone out 1/4" TRS jack
- using same 3.5mm cable as above, except TWO adapters.
- mono TS instrument cable.

- JVC Component dual cassette deck - headphone out 1/4" TRS jack
- using same 3.5mm cable as above, except TWO adapters.
- mono TS instrument cable.

- Sony home stereo amplifier - headphone out 1/4" TRS jack
- using same 3.5mm cable as above, except TWO adapters.
- mono TS instrument cable.

- Peavey Audition 20 practice guitar amp - headphone and line out 1/4" mono TS jacks
- using my .mp3 as line into the Peavey amp
- mono TS instrument cable.

So, wave-rider, I read that note that the PHA-1 originally came with it's own 1/4" to 3.5mm TRS cable - so that's why I kept thinking it may be some sort of phase canceling. So I bought a correct 1/8" to 1/4" TRS, and tried all the combinations above again, and still have the same results.

And no, the Mix L and Mix R pots on the front panel don't give me any boost. They have no noticeable effect on the level.

I've contacted Ampworks.org about repairs, since they're semi-local to me. Has anyone dealt with them before?

Thanks,
-placeboe

placeboe · #7 08-23-2010, 05:06 PM

Hey Jeff,

Sorry, you must have posted while I was typing up the last reply. I actually checked the .mp3 and cable combination with the Peavey guitar amp, and it worked fine... so all the more I think I might have an on board problem with the PHA-1.

Thank you,
-placeboe

gregbackstrom · #8 08-23-2010, 05:21 PM

Quote:

Originally Posted by placeboe

Hey Jeff,

Sorry, you must have posted while I was typing up the last reply. I actually checked the .mp3 and cable combination with the Peavey guitar amp, and it worked fine... so all the more I think I might have an on board problem with the PHA-1.

Thank you,
-placeboe

I'm having the same problem with my PHA-1. I've had mine for years, and the only problem I've had is with the stereo-mono switch, which I easily repaired. I'm going to take mine apart to see if cleaning and/or reseating cables or IC's solves the problem (I've already cleaned the jacks). If it doesn't, I'll have to try getting the company that Raven recommended for repairs to respond to my emails. They didn't respond to my inquiries the first time I tried.

In the meantime, I've moved on to a CafeWalter Headphone Amp. They work really well, although I think there may be something wrong with the LED on mine. It sounds great, though ...

Greg

placeboe · #9 08-23-2010, 07:27 PM

Hey gregbackstrom,

I actually did some web searches and found the number for Tibetan Monk Audio - owner Steven Rabe, Granada Hills, CA - and guess who answered? Yep, Steve himself. After slaughtering the pronunciation of his name (sounds like 'ray-bee', instead of rabe as spelled - those are one of the little lessons that you just learn the hard way) - he didn't sound like he was interested in talking about headphone amps, so I only got a couple questions off before politely ending the conversation.

He stated that the repair part of the Raven Labs business had been bought out by someone that could be contacted at mbollero@yahoo.com. Well, I didn't have the heart to tell Steven that I'd already tried contacting them (as this was the e-mail contact left on the Raven Labs website before it went defunct).

So, I looked at the Cafe Walter - and it was $175+shipping. I was going to buy one, until I read more about the PHA-1 and decided it had more features I'd use - so that's what I have now.

Actually, I found this online at Guitar Center Vegas, and they tested it completely before I bought it (and it was much less than the Cafe Walter price) - which is why I was so mad it didn't work when it arrived. They told me they used an Iphone with a 1/8" to 1/4" TRS cable and it worked fine before they shipped it out to me. (gurrgh)...

Thanks, placeboe.

placeboe · #10 08-23-2010, 08:03 PM

Took a bunch of closeup photos of the inside of this amp. Uploaded them to photobucket, but can't figure out how to get the URL's for each on this forum... sorry noobie...

http://s277.photobucket.com/albums/k...0Labs%20PHA-1/

placeboe · #11 08-23-2010, 08:09 PM

Okay, click on the link in previous post - then click on SLIDESHOW button when you get to Photobucket page. The slideshow is very nice, and I put comments on each photo.

scotch · #12 08-23-2010, 08:15 PM

Any competent amp bench tech should be able to diagnose & fix it. There aren't many components inside compared to a typical ss amp.

I've had a PHA-1 for over a decade & it still works perfectly. It sounds great!

placeboe · #13 08-23-2010, 08:56 PM

The instrument in's and their controls (main volume, eq, headphones out) all work fine, and really sound great. The line out works fine also, as I tested the preamp function with no problems. Haven't tried the Aux Send yet - as I'm not sure how that is supposed to be used. Any suggestions?
Thanks, placeboe.

scotch · #14 08-23-2010, 10:05 PM

It wouldn't surprise me if one of those capacitors has failed or something else simple. Again, I'd suggest taking it to an amp tech. There's so few parts to test that they might even enjoy working on something so easy!

placeboe · #15 08-23-2010, 10:25 PM

Yeah, it looks so straightforward even a DIY'er could handle it... but maybe not me. ;(

I so want to be knowledged in electronics, but guess I missed the boat on that career path.

eekmeg · #16 09-10-2011, 09:36 AM

Does anyone know what type of IC's are used in the PHA-1? An engineer friend of mine looked over mine and found that an IC was fried. He was unable to figure out it's value or any other info about it. If anyone has any info, I'd be greatly appreciative.

Thanks