Bias will be lowest with the bias pot at it's highest reading. Don't try it without the bulb unless you can get bias reading zero.
jwilhelm
Thanks, now I have no problems to set the bias to zero.
You are there always to give members a helping hand🙂
Eivind S
Thanks, now I have no problems to set the bias to zero.
You are there always to give members a helping hand🙂
Eivind S
Did Pete ever finish Spooky (Leach) Version 2 with real parts beyond simulation? He told me to wait. I now can't find any of Pete's posts. Is he all right? I heard that his health improved? Ray ( G.R. Hughes)
jwilhelm
Slewmaster sounds great with a "slam" in the bassregion I never heard in other of my builds. But there are plenty of details too.
With no signals connected it is dead silent in the loadspeakers. With a signal connected I can hear a very low hum. I must put my ears close to the loadspeaker to hear this.
Any cure?
Input is isolated from chassis. One transformer and one power unit.
Eivind S
Slewmaster sounds great with a "slam" in the bassregion I never heard in other of my builds. But there are plenty of details too.
With no signals connected it is dead silent in the loadspeakers. With a signal connected I can hear a very low hum. I must put my ears close to the loadspeaker to hear this.
Any cure?
Input is isolated from chassis. One transformer and one power unit.
Eivind S
Hum can be hard to cure. Is it present when just one channel is connected or is it happening only when connected in stereo?
No IPS is the input.board,what is the input board you are using?
Exactly what Terry ask.
Kypton ND is a CFA(Current Feedback amplifier) IPS.
It isn't an easy way to ended up without any hum.
I had to short d1/d2/R10 to get rid of hum/buzz on mine. Might be worth trying.
On mine the noise would increase if touching the input cap with my finger.
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If the hum only appears when connected in stereo it is likely coming from a ground loop. The best fix I've found for this is dual supplies. This also greatly improves stereo separation/ sound image.
I am temted to try the "one star point method" and see whats happen. To this one point I will lead zero (one of course) from Slewmaster PCB, zero from power bank(also only one) and the minus(-) from loadspeaker terminal. Same will be done from the other channel. Have anyone tried this?
Think I will try this before your "method", yngvejos.
By the way, the hum level depends on what is connected. Different CD player connected result in different hum levels(!?)
thimios: Is other IPS better when it comes to the risk of hum?
Eivind S
Think I will try this before your "method", yngvejos.
By the way, the hum level depends on what is connected. Different CD player connected result in different hum levels(!?)
thimios: Is other IPS better when it comes to the risk of hum?
Eivind S
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jwilhelm
Yes, the hum is there only when stereo is connected. But double trannies and powerbank; there is no room for that.
Eivind S
Yes, the hum is there only when stereo is connected. But double trannies and powerbank; there is no room for that.
Eivind S
If the hum is only happening when two inputs are connected, it is likely caused by excessive current flow through the signal grounds. One cheat we used to do in car audio was to leave one ground shield in the RCA cables connecting the amp to the source open (disconnected). It's not a perfect fix, but the loop is removed and both channels will share a single ground path. Another option was a signal isolation transformer. This is also not an ideal fix.
A single transformer can be used with dual rectifiers and supply reservoir capacitor banks. This takes more space, but not as much as dual transformers. This works very well.
A single transformer can be used with dual rectifiers and supply reservoir capacitor banks. This takes more space, but not as much as dual transformers. This works very well.
Hum in Slewmaster
jwilhelm: The "car" method: Yes, I now about this way to fix a hum loop. I have used it with good results before, but wih my Slewmaster it did not work. The hum went loader!!
Dual rectifiers could be a solution, but then I have to rebuild the reservoir capacitor bank. As you can see from the picture, that will be some job and I also have to buy a new "bank".
jwilhelm: The "car" method: Yes, I now about this way to fix a hum loop. I have used it with good results before, but wih my Slewmaster it did not work. The hum went loader!!
Dual rectifiers could be a solution, but then I have to rebuild the reservoir capacitor bank. As you can see from the picture, that will be some job and I also have to buy a new "bank".
Attachments
ReadD.Joffe and implement his HBRR + HBRL.
What meausrement do you get for output Hum + Noise on the 199.9mVac sacle of your DMM? I suspect you have between 0.3mVac to 1mVac of H+N at output when stereo interconnects are connected and vol pot turned down to zero.
Do you have 0.0mVac when the two inputs are shorted?
That's a nice big bank of capacitors. No problems with instantaneous current delivery. You only need connect the ground busses at the end of the run.
My slew masters are all mono blocks so sorry no help from me. I did try a stereo version on the bench with a single supply and had a similar problem to you. One input hooked up was OK but if both were hooked up there was hum. I never solved it.
My slew masters are all mono blocks so sorry no help from me. I did try a stereo version on the bench with a single supply and had a similar problem to you. One input hooked up was OK but if both were hooked up there was hum. I never solved it.