Persistant...stubborn...maybe some of both 
I measured the DC voltages either side of the plate resistor between channels at idle and with music.
Grid bias at 10.52Vdc L and 10.57Vdc R
Left supply side: 21.06
Left plate side: 10.26 (10.88 with 1Khz test tone playing)
Right supply side: 21.06
Right plate side: 10.34 (10.7 with test tone)
What voltages do you get Kevin? Or anyone else? For reference 1Khz test tone, 367mV input, volume full.
These voltages seem pretty close to me....probably not enough to cause the AC output loss in the right channel...or should they be exactly the same?
Do you think it is worth emailing the mfg Kevin or just change the resistor to compensate? It's certainly faster to just change it to a few close values that I have on hand and see what happens. Other's on here could probably figure out the math and get the right value....assuming that will even accomplish what I am hoping.
I'm kinda surprised NP hasn't chimed in a said just change the left resistor to a 390k and enjoy lol.
I measured the DC voltages either side of the plate resistor between channels at idle and with music.
Grid bias at 10.52Vdc L and 10.57Vdc R
Left supply side: 21.06
Left plate side: 10.26 (10.88 with 1Khz test tone playing)
Right supply side: 21.06
Right plate side: 10.34 (10.7 with test tone)
What voltages do you get Kevin? Or anyone else? For reference 1Khz test tone, 367mV input, volume full.
These voltages seem pretty close to me....probably not enough to cause the AC output loss in the right channel...or should they be exactly the same?
Do you think it is worth emailing the mfg Kevin or just change the resistor to compensate? It's certainly faster to just change it to a few close values that I have on hand and see what happens. Other's on here could probably figure out the math and get the right value....assuming that will even accomplish what I am hoping.
I'm kinda surprised NP hasn't chimed in a said just change the left resistor to a 390k and enjoy lol.
Hello DIYers,
I'm currently planning my B1K build, but I've still some questions regarding the setup with a phono pre amp. I'm sorry for the question being pretty basic, but I'm still a beginner in this topic.
I would like to build the Pearl II in the future as phono pre and I'm currently planning a source select via relays and an attenuator also by switching resistors by relays. Now I've different possibilities regarding the overall wiring of components and I'm not sure which one is going to work fine.
It's either:
Record player going into Pearl II obviously and then to Source select followed by an Attenuator and into B1K, which is then directly fed into Power Amp. The other sources go through source select into the same attenuator.
This results in records being amplified by the pearl II and afterwards again by the B1K.
Or:
Record player going into pearl II again an then into an 2 channel attenuator an afterwards to source select, while other sources go to the other channel of the attenuator followed by the B1K and then to source select which output is connected to the power amp.
The means records aren't amplified by the B1K, but the Pearl II.
Any recommendation which setup is correct/better?
The record player has 4mV output and the Phono pre has 55dB gain. The maximum output voltage of the PC sound card as one source is 2Vrms.
B1K gain is 16dB and power amp gain is 37bB. The attenuator is going to have a constant output impedance of 10kOhms.
Are there any other concerns I'm missing?
Thanks in advance and have a nice day everyone.
I'm currently planning my B1K build, but I've still some questions regarding the setup with a phono pre amp. I'm sorry for the question being pretty basic, but I'm still a beginner in this topic.
I would like to build the Pearl II in the future as phono pre and I'm currently planning a source select via relays and an attenuator also by switching resistors by relays. Now I've different possibilities regarding the overall wiring of components and I'm not sure which one is going to work fine.
It's either:
Record player going into Pearl II obviously and then to Source select followed by an Attenuator and into B1K, which is then directly fed into Power Amp. The other sources go through source select into the same attenuator.
This results in records being amplified by the pearl II and afterwards again by the B1K.
Or:
Record player going into pearl II again an then into an 2 channel attenuator an afterwards to source select, while other sources go to the other channel of the attenuator followed by the B1K and then to source select which output is connected to the power amp.
The means records aren't amplified by the B1K, but the Pearl II.
Any recommendation which setup is correct/better?
The record player has 4mV output and the Phono pre has 55dB gain. The maximum output voltage of the PC sound card as one source is 2Vrms.
B1K gain is 16dB and power amp gain is 37bB. The attenuator is going to have a constant output impedance of 10kOhms.
Are there any other concerns I'm missing?
Thanks in advance and have a nice day everyone.
The attenuator in the B1K, as well as almost every preamp ever, is placed after the selector but before the active circuit. So both of your setups are kind of describing the same thing.
As you need a knob to use for volume, building the B1K as a preamp with select and volume seems the way to go, I.E., normally, but with the cool relays, and build the pearl also as normal.
As you need a knob to use for volume, building the B1K as a preamp with select and volume seems the way to go, I.E., normally, but with the cool relays
, and build the pearl also as normal.Persistant...stubborn...maybe some of both
I measured the DC voltages either side of the plate resistor between channels at idle and with music.
Grid bias at 10.52Vdc L and 10.57Vdc R
Left supply side: 21.06
Left plate side: 10.26 (10.88 with 1Khz test tone playing)
Right supply side: 21.06
Right plate side: 10.34 (10.7 with test tone)
What voltages do you get Kevin? Or anyone else? For reference 1Khz test tone, 367mV input, volume full.
These voltages seem pretty close to me....probably not enough to cause the AC output loss in the right channel...or should they be exactly the same?
Do you think it is worth emailing the mfg Kevin or just change the resistor to compensate? It's certainly faster to just change it to a few close values that I have on hand and see what happens. Other's on here could probably figure out the math and get the right value....assuming that will even accomplish what I am hoping.
I'm kinda surprised NP hasn't chimed in a said just change the left resistor to a 390k and enjoy lol.
Thank you for raising this issue Steve. I noticed a small channel difference and measured aproximately a 2db difference 30 cm from the woofer on pink noise. When I feed the B1K a 1KHz tone at full volume from my DAC I get 7.53V in one channel and 8.18V in the other with the potentiometer set to max. I am also wondering whether I got a faulty nutube?
At first thanks for the fast answer. In the first case, when playing vinyl it gets amplified by the Pearl, then the B1K and afterwards by the power amp.
In the second one it gets only amplified by the Pearl and then directly by the power amp.
So there should be a difference at least in gain right? So the summarized question remains: Is it allowed/wise to feed the Output of the Pearl into the B1K?
but with the cool relays
This is mainly because I'd like to have a remote control. So I have the usual knobs but also a remote.
I'm in the process of starting my build of a Korg B1 and have a similarly related question. I don't want to use the Korg B1 as a headphone amp as such (I just completed a Whammy and it sounds great driving my Focal Elears) but I will be using the B1 to feed an M2x and would like to have the option to plug my Focals in somewhere along the line. From what I've read in some of the earlier posts it doesn't look like I can connect them at the output of the B1. Not sure if connecting them directly to the output of the M2x is the answer either.
Any help on this would be much appreciated.
All the best,
Gary
As the DC bias on the grid is adjusted (altering the plate DC) you will
vary the gain as well as the distortion. If you have the ability to measure
gain and distortion you could optimize either of these, and occasionally
both. From my experience the 8% difference in gain is a little more than
average. Of course, mine has twin volume controls....
As a test I lowered the plate resistor of the right channel to 290k (from 330k) but all that did was lower the AC output even more...I went from 2.1Vac to 2.0 . Opposite of what I expected....unless I need to lower the 1K resistor as well. Doesn't less resistance = more voltage in = more voltage out? Even the 1K resistor and Q1 should have been seeing more voltage I thought....
. Opposite of what I expected....unless I need to lower the 1K resistor as well. Doesn't less resistance = more voltage in = more voltage out? Even the 1K resistor and Q1 should have been seeing more voltage I thought....
I know, sorry for lack of details...It's just my frustration coming out. I've been trying to track down noise on the mains line for two days now. I don't know where to begin explaining the steps I've taken trying to track this down. I could write a page at least (I will start a new thread somewhere). Using a borrowed Quad 306 was just the last of many steps in trying to isolate the issue. the result of this attempt was a loud siren like noise coming from the tube. I know this because I can put my finger on the tube and make it stop to some extent.
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If you plot the load line on the triode curves, you will see that the maximum gain is with a horizontal load line (infinite plate load). This produces the greatest plate voltage swing for a set AC grid input. A smaller plate load (sloped load line) produces a smaller plate voltage swing for the same grid input (and same operating point).As a test I lowered the plate resistor of the right channel to 290k (from 330k) but all that did was lower the AC output even more...I went from 2.1Vac to 2.0
well , K B1's output buffer is buffering ........ so no way that something is coming back from 306's input and unsettling tube ..... amp doing this will long time ago make your ear bleed and speakers cry
must be something with gnd and used supply for K B1
I think your on to something there. I use a long run of interconnect from preamp to amp (8 ft). No noise with Quad off. No change with volume.
So the tube physically makes a sound?? Does it happen if the Quad is on, but you use a cheater plug to break the ground connection on the amp? Or use the cheater plug on the preamp? How about if you physically connect the amp and preamp chassis with a wire? Was there any recent change to the wiring in the house?
So far....R channel with a 470K plate resistor is in perfect balance with the left channel using the stock 330K. (shrug). Whatever...lol. I have no explanation. It is still a few mV off at low (more normal) volumes, but I can no longer tell, that might even be normal. At least I can enjoy it now and cross my fingers that nothing else goes wrong with it. Running at 21.06Vdc on the supply side both channels, heater is exactly .6Vdc both channels, bias is at 11.0vDC...just cause that's where it ended up lol.
Listening to my Zaph audio two-ways with the B1K, deep imaging and crystal clarity. There is some hum and noise when I put my ear up to the speaker, but 2 feet away you cannot hear it. Though cover is still off at this point.
Listening to my Zaph audio two-ways with the B1K, deep imaging and crystal clarity. There is some hum and noise when I put my ear up to the speaker, but 2 feet away you cannot hear it. Though cover is still off at this point.
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