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Calling All "Vintage" Integrated/Receiver Owners - Page 486

post #7276 of 13101
Quote:
Originally Posted by rated1975 View Post

Great thread. Subscribed.
Using LCD2's, I recently gave up on my maxxed Woo WA6 after i dusted off an old 90's Onkyo receiver i had just sitting in a cupboard. Wow, it simply does everything better than that WA6. The LCD's have simply jumped into another realm of performance. Funny thing is, ive never really rated the Onkyo as a good amp for speakers, at best average only. But its headphone jack seems to work wonders with the the right cans.
Think i have a case of the vintage amp bug. The quest begins!

Welcome, congrats and sorry about your wallet! Kind of like discovering a whole new realm of sound, isn't it?!
post #7277 of 13101
JoeHalo, nice looking HPM-60's, and nice work on the stands! The HPM-60's sound really terrific and can often be had for much cheaper than the famed HPM-100.
post #7278 of 13101

Last night I did something real dumb.  Tried adjusting the bias of my sx-950 after re-lubing the switches and seem to have failed miserably and could really use some input.  Truth be told, I really don't know what the hell I'm doing lol.

 

Pg 29 of the sx-950 manual has the dc-offset biasing procedure:  http://www.hifiengine.com/library/pioneer/sx-950.shtml

 

Then I read this: http://www.audiokarma.org/forums/showthread.php?t=459160

 

Basically someone said don't worry about the resistors on the power in jacks, just set volume to 0 with no speakers and you're good to go.

 

OK so I tried it. Problem is, it seems as if the "adjusting" I am doing to the trim pots is not affecting any readout on my multimeter at all.  From min to max, no changes across any of the 2nd, 3rd, and 4th measuring points (first point seems to be adjusting ok).

 

I gave up in sheer frustration last night and hope I didn't mess anything up :(

 

I'm headed to Fry's to try to find 5.1-k ohm resistors and bare RCA plugs; it seems they are sold in different wattages online.  Good thing the manual doesn't state what kind of wattage to look for...

post #7279 of 13101
Quote:
Originally Posted by MrQ View Post

^They look like they are in really good condition. Are you going to get the crossovers recapped? I did that to my HPM 100's and it really made a difference.
They are in very good condition, just a few minor scuffs to the vinyl. I am considering recapping. Would it be difficult to do myself you think?

Quote:
Originally Posted by Skylab View Post

JoeHalo, nice looking HPM-60's, and nice work on the stands! The HPM-60's sound really terrific and can often be had for much cheaper than the famed HPM-100.
Thanks Skylab! I was about to buy some stands off eBay but thought why not give it a go myself first.
post #7280 of 13101
Mr. Sneis, did you attempt to adjust the DC Offset, or the Bias (or both)?
post #7281 of 13101
I believe both. Its pg 29
post #7282 of 13101
OK. I could have helped you with the DC Offset, but I can't help with the Bias. It's not something to mess around with unless you REALLY know what you are doing. With DC Offset, the very worst thing that can happen is that you won't be able to get the amp out of protection. Mis-adjusted bias can fry the output devices.

In spite of what the manual says, I always measure DC Offset on Pioneer amps as the speaker terminals. You can do that because the outputs are not capacitor coupled.

But I've never attempted a bias adjustment, so can't help you there, sorry. You might want to sign up for AudioKarma if you haven't already and ask in the Pioneer forum.
post #7283 of 13101
Quote:
Originally Posted by Mr.Sneis View Post

Last night I did something real dumb.  Tried adjusting the bias of my sx-950 after re-lubing the switches and seem to have failed miserably and could really use some input.  Truth be told, I really don't know what the hell I'm doing lol.

 

Pg 29 of the sx-950 manual has the dc-offset biasing procedure:  http://www.hifiengine.com/library/pioneer/sx-950.shtml

 

Then I read this: http://www.audiokarma.org/forums/showthread.php?t=459160

 

Basically someone said don't worry about the resistors on the power in jacks, just set volume to 0 with no speakers and you're good to go.

 

OK so I tried it. Problem is, it seems as if the "adjusting" I am doing to the trim pots is not affecting any readout on my multimeter at all.  From min to max, no changes across any of the 2nd, 3rd, and 4th measuring points (first point seems to be adjusting ok).

 

I gave up in sheer frustration last night and hope I didn't mess anything up :(

 

I'm headed to Fry's to try to find 5.1-k ohm resistors and bare RCA plugs; it seems they are sold in different wattages online.  Good thing the manual doesn't state what kind of wattage to look for...

 

My first attempt at what you tried above fried the left side of a nice Marantz 140 amp.  The right side bias adjusted just fine.  When I tried the left side, moving the pot didn't make any difference at all.  I got frustrated, removed a probe without powering down the amp and ZZZZZZTTTTTTT, dead left side.  There was smoke and sparks, so I was sure something bad happened.  If you didn't cause a smoke/spark event, you may be OK.  

 

How close is the readout on your multimeter to where the bias needs to be set?


Edited by BmWr75 - 5/19/13 at 3:08pm
post #7284 of 13101
Quote:
Originally Posted by BmWr75 View Post

My first attempt at what you tried above fried the left side of a nice Marantz 140 amp.  The right side bias adjusted just fine.  When I tried the left side, moving the pot didn't make any difference at all.  I got frustrated, removed a probe without powering down the amp and ZZZZZZTTTTTTT, dead left side.  There was smoke and sparks, so I was sure something bad happened.  If you didn't cause a smoke/spark event, you may be OK.  

How close is the readout on your multimeter to where the bias needs to be set?

Pretty close actually. Off maybe .05 volts on 3rd and 4th. Calls for 20mv and is at 15... And .04v on the second which calls for 0v. Again adjusting seems to do nothing based on what my multimeter tells me so I don't think its any different than before I started?
Edited by Mr.Sneis - 5/19/13 at 7:29pm
post #7285 of 13101
For DC Offset, are you using the mV scale on your MultiMeter? You would like to see DC Offset under 10 mV if possible, but in practice attaining exactly 0mV given how sensitive the trim pots are is very tough. I managed to get mine under 10mV, but that took some work! Getting exactly 0 would have just been luck.
post #7286 of 13101
Thread Starter 

Lol, I have ocd when it comes to getting the 0 on dc offset. I think I may look at it as a challenge that I refuse to loose.  I always reach my goal though...well sort of. But it's really time wasted when anything under 10 is fine and doesn't take that long to attain. But the frustrating part is after adjusting the other side, the previous side has slipped to something like 3 or 4mv. And before you know it, you've spent 20+ minutes between both pots trying to get both of them to remain at 0 when it should have been a 2 minute job.biggrin.gif

post #7287 of 13101
Hey guys. My Harman kardon 430 has a buzz and we've been talking about taking it in to get fixed for awhile. Now would that mean recapping? How much does that usually run in price? I've read some of these repair places charge just for an estimate... I need to take my Harman kardon 670 in to get the tuner twine fixed and the impossible to get to mini red lights replaced. Ive looked online and found The Stereo Workshop in Eugene, OR or someone in Portland.
post #7288 of 13101

WELL guys.  I am indeed a complete idiot.  I stared at the manual for a long while and it hit me that I mis-read the diagram for where the trim pots actually are.  The the trimmers are in order of VR-1,3 2,4 instead of 1,2,3,4.  So when I went to measure the matching points it would appear that my adjusting had no effect on points 2 and 3 because I had them reversed!

 

Got it back in spec - hopefully I won't blow up the house.  Fingers crossed.

post #7289 of 13101
Quote:
Originally Posted by joehalo View Post


They are in very good condition, just a few minor scuffs to the vinyl. I am considering recapping. Would it be difficult to do myself you think?
 

I sourced the parts myself, then had a mate do the recap for me.

 

Here's some posts you might find useful...HPM-60 Recap HPM-60 Recap 2

post #7290 of 13101
Quote:
Originally Posted by Mr.Sneis View Post

WELL guys.  I am indeed a complete idiot.  I stared at the manual for a long while and it hit me that I mis-read the diagram for where the trim pots actually are.  The the trimmers are in order of VR-1,3 2,4 instead of 1,2,3,4.  So when I went to measure the matching points it would appear that my adjusting had no effect on points 2 and 3 because I had them reversed!

 

Got it back in spec - hopefully I won't blow up the house.  Fingers crossed.

 

 

The devil is in the details!!  beerchug.gif

 

Glad you figured it out.

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