I will sum up why the DCzb1 is excellent. I recently built a new tube preamp and didnt have a 50k pot for it, so i just wired it up and used the dcb1 as a volume control. Today i added the pot to the tube pre and removed the dcb1. Removing the dcb1 changed the sound so little that i would have a hard time telling whether it was in the chain or not. For a passive pre, you cannot say more.to Nelson and Salas.
That would be the 6V6 tube line preamp for sure. What type/make of pot? Haven't seen news in the tubes forum about it from you...weird. Busy taking pictures & listening, or something blew meantime?
Out of town, so if it blew up, I don't know it yet. The pot is stepped attenuator from fleabay. Has surface mount resistors and gold s shaped contacts for pop free volume control. All for 12.99. Can you tell I got sucked into the marketing. Reworked all the input wires with tightly twisted pairs. Looks good on the inside and out now. Still got a small hum on right channel. Very small with volume all the way up. Will track it down with oscilloscope. Pics are in photo gallery of tube forum. New PSU up next.
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that's the same summary as I found.I will sum up why the DCzb1 is excellent. I recently built a new tube preamp and didnt have a 50k pot for it, so i just wired it up and used the dcb1 as a volume control. Today i added the pot to the tube pre and removed the dcb1. Removing the dcb1 changed the sound so little that i would have a hard time telling whether it was in the chain or not. For a passive pre, you cannot say more.
The DCB1 did not improve the sound quality coming from the speakers.
But, it did allow longer and thus more capacitive cables, to be used as interconnects.
I have tested the leds, and as far as I observed all were in good shape. No changes. The other ledgroup of five that is not lighting up, usually start with a lightup, but dims out pretty fast.
The 12V toroids is ok.
The 10 ohms is showing 0,13Vdc
The first irfp9240 is showing 7,19Vgs and the irfp240 9,3Vgs (pin 1-3)
The seconds irfp is showing the same, but on pin 1-2
I was thinking about changing the K170. I have some spare sk170-gr. Would those be ok for diagnosing those fets?
This is so frustrating, so more advises help would be appreciated.
The 12V toroids is ok.
The 10 ohms is showing 0,13Vdc
The first irfp9240 is showing 7,19Vgs and the irfp240 9,3Vgs (pin 1-3)
The seconds irfp is showing the same, but on pin 1-2
I was thinking about changing the K170. I have some spare sk170-gr. Would those be ok for diagnosing those fets?
This is so frustrating, so more advises help would be appreciated.
It's late, but I couldn't bear the suspense so I plugged her in.
10.51 and 10.50 volts with DC offset about 1.4 mV on both sides. Seems to be just about right! Those red LEDs are very... red. Reminds me of a fire truck!
I'm a bit torn about whether or not to install a pot. I have a LCDuino that I've built but have yet to case that I was going to use as a stand alone attenuator. But having a pot for the DCB1 as well seems like a good idea just in case. I think I have a couple Alps pots lying around. But I think they're 50K. If I remember correctly, the DCB1 would be better off with 20K-ish?
10.51 and 10.50 volts with DC offset about 1.4 mV on both sides. Seems to be just about right! Those red LEDs are very... red. Reminds me of a fire truck!
I'm a bit torn about whether or not to install a pot. I have a LCDuino that I've built but have yet to case that I was going to use as a stand alone attenuator. But having a pot for the DCB1 as well seems like a good idea just in case. I think I have a couple Alps pots lying around. But I think they're 50K. If I remember correctly, the DCB1 would be better off with 20K-ish?
Yes its normal bcs of the differences in the unsorted JFETs that are driving them, and for the groups of 3 to generally have more current available shining a bit more than the groups of 5 due to there is more voltage available to their JFETs giving them more IDSS.
No, it has ~270R output impedance, even 600 Ohm headphones would need 60R output impedance for good dynamics, and more current available from bias. Not to mention the lack of gain for the inefficient ones.
No, it has ~270R output impedance, even 600 Ohm headphones would need 60R output impedance for good dynamics, and more current available from bias. Not to mention the lack of gain for the inefficient ones.
Will a 30VA, 2x15AC R-Core be able to handle 600mA HotRod?
Got some nice 3.3R Mills from T-B I'd like to use.
Alternatively I can go for 5R (Vishay) resistors and keep Mills for a BiB or something.
I'm going to use Stealth II rectifiers (I have both 600V, 4A and 600V, 8A parts available). I suppose these won't need any heatsinking?
Got some nice 3.3R Mills from T-B I'd like to use.
Alternatively I can go for 5R (Vishay) resistors and keep Mills for a BiB or something.
I'm going to use Stealth II rectifiers (I have both 600V, 4A and 600V, 8A parts available). I suppose these won't need any heatsinking?
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30VA 2*15Vac has a maximum continuous AC current of 1Aac
This transformer feeding a capacitor input filter will be able to supply a maximum continuous 500mAdc to each polarity.
At this output it will run hot.
I recommend you take ~250mAdc from each winding as the maximum cool running output.
This transformer feeding a capacitor input filter will be able to supply a maximum continuous 500mAdc to each polarity.
At this output it will run hot.
I recommend you take ~250mAdc from each winding as the maximum cool running output.