Anyone have a datasheet for 6KE6? I can't find one anywhere. I just got small pile of 6GV5 and there was a 6KE6 in there with it.
That's kinda sparse info there, eh?
On the upside I did just notice for the first time that they have links to a bunch of receiving manuals though.
Pete, the guy who created this red board, has a web site. Somewhere on there (I don't have access right now) there are pages with more books from the vacuum tube era than you can ever read, all scanned to PDF and freely downloadable. The RCA RC30 tube manual is there (I think, I downloaded it somewhere). I believe the GE essential characteristics book is there too.
Data on 6KE6 is rather sparse. I have used sweep tubes that I have zero data on before. If you only have 1 of them it is not worth worrying about. If the internals look exactly like something you have a bunch of you can try pairing it with one of them. Pay attention to how it biases up and the distortion at varouos power levels.
Data on 6KE6 is rather sparse. I have used sweep tubes that I have zero data on before. If you only have 1 of them it is not worth worrying about. If the internals look exactly like something you have a bunch of you can try pairing it with one of them. Pay attention to how it biases up and the distortion at varouos power levels.
I am sorry to disturb again but honestly guys......I am going insane. I just finished resoldering everything back on the board. Yes I desodlered everything and resoldered new components. The problems are still there:
1. transformer gets hot. Unloaded not as hot but still very warm
2. the output is still very low.
Still waiting for the new tubes but I don't get it: if a signal is that good, no distortion, excellent detail, dynamic ecc ecc how can it be that the only thing missing is "gain"? also...if I had made a mistake with a resistance value I would have had to make the same mistake in the other channel for the amp to work symmetrically.
The onyl thing I changed from Pete's design is the IXYS part. I substituted the IXYS part with a SUPERTEX DN2540 chip. Same pinout. I changed the R37/R39 values to 56 ohms in order to achieve the same current level. Could this be it?
Could someone please measure the voltage across R37/R39? It would be a huge help...
The other option is that the input sensitivity is really too high for the signal I use. A very mismatched set of amplifier + source could account for all these problems?
Thanks
P.s. I am sorry for posting these stupid messages but I am really frustrated. The quality of the music is just excellent. I have spent hours enjoying the best Duke Ellington I have ever heard out of an amplifier.
1. transformer gets hot. Unloaded not as hot but still very warm
2. the output is still very low.
Still waiting for the new tubes but I don't get it: if a signal is that good, no distortion, excellent detail, dynamic ecc ecc how can it be that the only thing missing is "gain"? also...if I had made a mistake with a resistance value I would have had to make the same mistake in the other channel for the amp to work symmetrically.
The onyl thing I changed from Pete's design is the IXYS part. I substituted the IXYS part with a SUPERTEX DN2540 chip. Same pinout. I changed the R37/R39 values to 56 ohms in order to achieve the same current level. Could this be it?
Could someone please measure the voltage across R37/R39? It would be a huge help...
The other option is that the input sensitivity is really too high for the signal I use. A very mismatched set of amplifier + source could account for all these problems?
Thanks
P.s. I am sorry for posting these stupid messages but I am really frustrated. The quality of the music is just excellent. I have spent hours enjoying the best Duke Ellington I have ever heard out of an amplifier.
Only had time to make a few measurements. With a B+ of 322VDC, I measure 3.11 VDC across R39 for a current of 15.5 mA. Screen grid voltage at Pin 6 of VT8 (6CB6) is 143 VDC. Plate voltage at VT8 (TP12) is 149 VDC. All measurements relative to ground except the voltage across R39.
interesting!
Thankyou drj759
I found out that plate voltage is 100v and not 149 (TP12 to gnd) on both channels! (tp12,tp11,tp8,tp10 all to GND)
Thankyou drj759
I found out that plate voltage is 100v and not 149 (TP12 to gnd) on both channels! (tp12,tp11,tp8,tp10 all to GND)
my B+ measures 310v across the red board...
Across R50/55/53/51 I get a drop from 300v to 100v.
If I want 150v plate voltage it stands to reason I must replace R51/r53/r50/r55 with 2w 22k resistors...
Across R50/55/53/51 I get a drop from 300v to 100v.
If I want 150v plate voltage it stands to reason I must replace R51/r53/r50/r55 with 2w 22k resistors...
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Progress:
It turns out the resistor value on the Supertex DN2540 was worng. By replacing the 56ohm resistor with a 150ohm one I managed to bias the tubes at 40mA and achieve a plate voltage on the 6CB6 of 170v.
Unfortunately I do not have any interemediate value so I am stuck with 170v.
Volume has increased slightly..
It turns out the resistor value on the Supertex DN2540 was worng. By replacing the 56ohm resistor with a 150ohm one I managed to bias the tubes at 40mA and achieve a plate voltage on the 6CB6 of 170v.
Unfortunately I do not have any interemediate value so I am stuck with 170v.
Volume has increased slightly..
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No...nothing has changed.
I measured the output of a source like an ipod. Normal music is in the mV range per channel (the dmm shows 0.006 - 0.008v at max volume)
Same music passing through the amplifier gets reduced beyond the dmm's ability to register.
🙁
cana anyone help me?
I measured the output of a source like an ipod. Normal music is in the mV range per channel (the dmm shows 0.006 - 0.008v at max volume)
Same music passing through the amplifier gets reduced beyond the dmm's ability to register.
🙁
cana anyone help me?
Yes...they all check out.
Also it stands to reason that I would have had to make the same mistake twice for the amplifier to be symmetrically NON working.
Is resistance value the only possibile explanation? I might go ahead and do the resistors again... desolder and resolder new selected and checked types but I doubt it would help...
P.s. Dagwood, great sig...I hope it is true!
If only I could get my hands on 2 IXYS IC I would be able to say that the problem lies elsewhere.
Also it stands to reason that I would have had to make the same mistake twice for the amplifier to be symmetrically NON working.
Is resistance value the only possibile explanation? I might go ahead and do the resistors again... desolder and resolder new selected and checked types but I doubt it would help...
P.s. Dagwood, great sig...I hope it is true!
If only I could get my hands on 2 IXYS IC I would be able to say that the problem lies elsewhere.
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Reading your posts has made me think about re-checking the values on my Red Board.
I am waiting on my Edcor Iron to arrive from the USA, had to ship through a friend as it was going to cost more than the trannies to ship them!!
I'm a newbie so the signature is down to experiance!
Cheers
I am waiting on my Edcor Iron to arrive from the USA, had to ship through a friend as it was going to cost more than the trannies to ship them!!
I'm a newbie so the signature is down to experiance!
Cheers
video 2011 08 18 13 18 46 - YouTube
youtube video.
DVD player, one channel only
everything maxed out.. in terms of volume
cell phone 1m from the amplfier. 2 8ohm speakers under the amp..
youtube video.
DVD player, one channel only
everything maxed out.. in terms of volume
cell phone 1m from the amplfier. 2 8ohm speakers under the amp..
What is the voltage limit of the coupling caps when using the external boost power supply? I was hoping to get by with 400v caps.
I am unsure of the speakers' sensitivity.....
Anyways the limit for thos speakers is 10 w (but I have tried with much bigger speakers...ordinarily I would have used some 40w speakers for these experiments).
the interesting thing is that if I hook up an electric bass (very very low output) I get an extremely low output from the speakers. the level is so low that I can hardly hear the strings being plucked on the bass and the electric sound is overwhelmed by the actual string sound..
Is this normal...?
As anyone hooked their DCPP to either a laptop maxed out or a bass/musical instrument maxed out? Are the results satisfactory?
Anyways the limit for thos speakers is 10 w (but I have tried with much bigger speakers...ordinarily I would have used some 40w speakers for these experiments).
the interesting thing is that if I hook up an electric bass (very very low output) I get an extremely low output from the speakers. the level is so low that I can hardly hear the strings being plucked on the bass and the electric sound is overwhelmed by the actual string sound..
Is this normal...?
As anyone hooked their DCPP to either a laptop maxed out or a bass/musical instrument maxed out? Are the results satisfactory?
I think the issue with the bass guitar straight into a power amp is that passive pickups are VERY low output. I've put guitar into phono inputs and still not gotten much. You need a lot more gain for guitar amplification.
On top of that, a strong word of caution about playing guitar through your stereo. Guitars create huge, nasty transients that can destroy speakers that aren't made to take the abuse. I learned that first person by playing a bass through a stereo. The result was dead voice coils.
Which leads me to a slight OT question. Is there anything about audio reproduction amplifier design that would make them susceptible to damage from those same transients? Or is it just the speakers that are in danger?
On top of that, a strong word of caution about playing guitar through your stereo. Guitars create huge, nasty transients that can destroy speakers that aren't made to take the abuse. I learned that first person by playing a bass through a stereo. The result was dead voice coils.
Which leads me to a slight OT question. Is there anything about audio reproduction amplifier design that would make them susceptible to damage from those same transients? Or is it just the speakers that are in danger?
The usual answer is NO. There are conditions where high power use can damage an amp, but it is a lack of design care that accomplishes it, not just running it into overload. For instance, an amp running grid current can be designed so that overload conditions draw too much and overheat the fragile grids( in comparison to the plates ).
cheers,
Douglas