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In Reply to: RE: BASH subwoofer amp posted by mark.korda@myfairpoint.net on August 17, 2016 at 20:01:04
Sounds like you may have some DC appearing on the speaker terminals during warm up.
Follow Ups:
Hi Tidycat, what do you mean by (floating) the 3 prong cords? Also Sayntjack, where would the DC come from? I thank both of you for your help on this. I'm writing Parts Express before I hit the hay. Thanks Mark.
Hi Mark, given that I'm not familiar with class D amplifier design, DC appearing on the output terminals may not be possible. However, the short lived hum that you hear is what I have experienced on solid state amplifiers during startup when the output circuit DC nulling goes out of balance. To check this, put a DC voltmeter on the speaker output terminals and monitor start up thru your hum period to see if DC is the offender. Jack
Hi Jack, thanks. I still have to try the first test. The Perry Mason show came up quick.
Jack you said monitor the speakers output jacks. Unless I'm wrong the outputs are on the amp and inside my cabinet. I remember attaching 2 wires from the BASH to the Titantic subs terminals on the speaker basket all done inside the cabinet. My cd players output cables go right to the amp which is screwed into the cabinet. I'm using Y cables so the other cd output cables go to a vacuum tube integrated stereo amp. the Heathkit AA-32.
There are terminals on the BASH sub amp that can go out to the main speakers but these are not used in the way I have bi amped. The speaker terminals on my tube amp go to my main speakers and not from the BASH's terminals for the main speakers. The BASH says it has a crossover or filter to channel off the highs. I don't know where I could use the multimeter but will try all things until I have to take the amp off the cabinet. I could do your test then.
I can live with this hum thing but since it didn't do it in the past Murphys Law might creep up on me if I don't do preventative measures. Thanks Jack and all of you. Keep those tests ideas coming. I can't help but get it right with the right peoples help...Mark Korda
Yup you are going to have to check those wires going to the driver for that DC.
Hi Awe-d-o and Airtime,
My BASH sub amp did not hum at all when I unplugged the RCA jacks from my cd player. Horray I hope! Maybe my old Magnavox 565 has to be put out to pasture. It had an exellent review back then and there were mods being done on it,AVA for example. The only reason I was still using it was that I treated it with kid gloves and I got on a forum where no one said the over sampling or whatever was out dated.
The other component in my room,turntable coming soon, is a 4 year old Samsung Blue Ray. I will sub that in for the Magnavox with you guys permission and see if that hum still comes around.
I had asked on another forum a while back; What was better audibly, the 1988 Magnavox or the 100 dollar Samsung Blue Ray? What do you guys think?
Airtime, I finally finished a project. The Weems Danish Pipes, with a little French in there for the Audax tweeter. Danish because of the Vifa co-ax's 6.5's I got for a song at Parts Express. I'm making the grills tonight. My brother gave me an Android tablet and I'm almost up to the picture chapter in my brand new dummy book. I will get my first picture to you.Thanks for the help...Mark K.
You're MAD Mark! Good luck with that project.
However it looks like it's time to retire the Magnavox. Don't worry CDP are pretty cheap these days. Heck even cheap ones now are better than the vintage ones.
Great to hear you solved the problem
charles
Hi Airtime, I hooked up the Blue Ray and theres nary a hum. Thanks so much! For testing I put on the Telarc Organ cd and I got the eerie feeling back that you get from that lowest low even with the volume very moderate. Also in rotation was Yes, Relayer cd and a Mapleshade sampler with a lot of sax. The Mapleshade cd's are the best I've ever heard but sometimes the content does not move me but awes me with its sonics.
Retiring the old Magnavox is like on Bonanza when your horse breaks a leg and you have to do it.
If you think I'm mad you gave me my new project idea from the Best Buy McIntosh story. A passive preamp switch box with Frankinstein style knife switches instead of toggles. You want garden hose interconnects?, well your going to need some big switches.....thanks so much Charles, and you other problem solvers too...sincerely Mark Korda.
I understand taking out a piece of gear and shooting it. I had to do that with my Luxman CDP. To this DAY it was the best CDP I've ever listened to. Smooooootth!!!! Never got that sound back.
Relayer was my favorite Yes album. I remember when it came out I would play it over and over again on that cheap little stereo I could only afford to own. From listening to those albums I knew I wanted a really good stereo. I even got to see Yes live at Madison Square Garden during that album release and Yes Songs.
As kids we would wait eagerly to see what the new album art cover would look like. It reminded me of the Beatle years waiting for their next album.
But I must say that when I say that McIntosh I actually giggles. What the hell is that thing! If you can find a Best Buy Magnolia store they carry very high end stuff. Fun to look at but in the end just eye candy.
I'm very happy with my SR-71s. My listening room is now a bedroom. So things have changed a lot.
Cheers
charles
Start with unplugging the source and just plug the sub into the ac outlet and see if it still hums. The removing the ground to alleviate a ground loop doesn't apply since the him goes away and there will be no ground loop with no source plugged in. See if it still hums with no source as a first test.
ET
"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936
Hi Awe-d-o-file and Airtime, I am going to do the test you both prescribed before my new favorite TV show Perry Mason. With nothing hooked up, that will be my old but reliable Magnavox 565 (1988) cd player, if it still hums for 10 to 15 seconds is it time to unscrew it out of the sub cab?
I have never really abused but babied the sub. When I put it in I noticed how cheap the volume and frequency pots were and I can't find the BASH company on the net even though these are going in Klipsch sub woofers and made in Canada. I'll let you know my results and I thank you both for helping me out.
Airtime, We have a Best Buy in South Portland. It is a zoo! The lights,the masses, the noises! It could drive a man insane! I got my Dell desk top there. Think 40 year old virgin workplace on steroids.
How in the world I wondered did McIntosh think of selling their wares there. McIntosh should have their own building like Lazy Boy has for recliners. They could sell other brands too! I think they could call it a Hi-fi store which are pretty much extinct in my parts. They used to be fun to go to. Going into Best Buy for me is like Robert Preston in your face playing 76 trombones.
Wandering around a Hi-fi store in the late 70's I heard the pint size Visonics near the Klipsch horns. The Visonics had a sub woofer. The eerie feeling felt and heard hooked me on subs. It was not at all loud.
I'll stop gabbing...thanks guys...Mark.
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