Some definite "crunchiness" in the midrange. Male vocals are a little raspy.
Strings are delightfully clear, though. Odd...
Strings are delightfully clear, though. Odd...
Things are smoothing out as the heat rises. This is much more apparent than it ever was before (in UL).
The image is more central, or at least central elements are more central than they used to be. Some would say a narrower sound stage, which I've always considered a negative comment. In this case it is rather a lack of artificially wide stage, I guess.
Perhaps I just really want to hear a difference. I dunno. On to some Rosenberg Trio.
The image is more central, or at least central elements are more central than they used to be. Some would say a narrower sound stage, which I've always considered a negative comment. In this case it is rather a lack of artificially wide stage, I guess.
Perhaps I just really want to hear a difference. I dunno. On to some Rosenberg Trio.
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Mine has a switch.
Amp is mostly in triode, but some speakers -- and some listening sessions -- prefer pentode.
dave
Crunchiness is gone. Volume/power is basically indiscernable from UL.
Seems like it has so much "control" over the drivers.
Enjoying this little experiment very much. Chicken's in the oven, second beer, more Rosenberg Trio. Loud!
Seems like it has so much "control" over the drivers.
Enjoying this little experiment very much. Chicken's in the oven, second beer, more Rosenberg Trio. Loud!
Anything short of ripping the PCB out and going 100% p2p, and relatively affordable (ie. New iron is not on the menu, yet).
That chimp amp is ridiculously good, for $3, but as I said in the other thread - I still like my tube amp better.
With this little (?) tweak, the gap just got larger.
I do have a Wiener on the way, though. Either it or the 7297 will become my "summer amp".
Switched to some Harry Manx (thanks to chrisb for turning me on to this band).
The central focus is still very apparent, but I realized there's considerably more depth. Harry's a lot more forward than I've heard him in the past, and the rest of the band is distinctly "back stage". I'm used to this sounding as if the stage is maybe 6 feet deep and I sit 20 feet back. Now I am in the front row and the stage is 20 feet deep.
The central focus is still very apparent, but I realized there's considerably more depth. Harry's a lot more forward than I've heard him in the past, and the rest of the band is distinctly "back stage". I'm used to this sounding as if the stage is maybe 6 feet deep and I sit 20 feet back. Now I am in the front row and the stage is 20 feet deep.
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I use 1K with EL34 and switch,
You could try diode enhanced U/L (slipstream) sound is close to triode with more power.. remember to watch the bias current when you change connection types.
The mod is simply a 1K to the tube and a diode from the U/L tap on the output Tx pointing towards the tube something like 1n4007 would do it.
Its mentioned here..however I fit a 1K on the tube side of the diode..
Hiend Audio, DIY, Hi-Fi, Stereo, Electronics site, for lovers of high-fidelity music reproduction. High-End Vacuum Tubes. Silicon. Do-It-Yourself Audio Systems. Schematics: amplifiers, speakers, horns, CD, DAC. Circuits, Topologies, Acoustics, Cables
I switch between RH/U,L slipstream/triode on SE you can use diode enhanced triode as well but I'm not a fan..🙂
NB important don't just replace the resistor with the diode the diode is in series with the resistor.
Regards
M. Gregg
You could try diode enhanced U/L (slipstream) sound is close to triode with more power.. remember to watch the bias current when you change connection types.
The mod is simply a 1K to the tube and a diode from the U/L tap on the output Tx pointing towards the tube something like 1n4007 would do it.
Its mentioned here..however I fit a 1K on the tube side of the diode..
Hiend Audio, DIY, Hi-Fi, Stereo, Electronics site, for lovers of high-fidelity music reproduction. High-End Vacuum Tubes. Silicon. Do-It-Yourself Audio Systems. Schematics: amplifiers, speakers, horns, CD, DAC. Circuits, Topologies, Acoustics, Cables
I switch between RH/U,L slipstream/triode on SE you can use diode enhanced triode as well but I'm not a fan..🙂
NB important don't just replace the resistor with the diode the diode is in series with the resistor.
Regards
M. Gregg
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Hi M.
I read the article, and it seems to me the author is claiming that the sound is actually better than triode; sort of a "best of all worlds" situation. It seems too good to be true, but I know I have to try it. 🙂
Since my amp topology didn't include the series resistor, I think I' just go with the diode. Are there any potential issues with using oversized diodes, such as 1N1200A ?
I read the article, and it seems to me the author is claiming that the sound is actually better than triode; sort of a "best of all worlds" situation. It seems too good to be true, but I know I have to try it. 🙂
Since my amp topology didn't include the series resistor, I think I' just go with the diode. Are there any potential issues with using oversized diodes, such as 1N1200A ?
A few points,
Use the resistor and diode...you should have a resistor in the U/L connection...its a must do! Even if the amp did not have one at all..
You can switch if you know what you are doing and set the bias at "normal level" so it just runs a bit low in other positions..
You only need a 1n4007 anything else is over kill and I don't use ultra fast they can create more problems.
The tubes might not last long with a direct connection..
The other point is that different connections will have different idle/bias current..so always check you are not over biasing the amp..(current at idle through the tube)
Remember a 1n4007 is 1A at 1000V ..this is a grid connection..so 1N4007 is overkill anyway..
The fact that the amp did not have a resistor in the first place to me is bad practice..remember the resistor voltage rating is important..
Look at the operating conditions RG2 in the datasheet from this link..(its a PDF) The push pull section..(the word pentode is above the PDF)
http://www.r-type.org/exhib/aaa0014.htm
Regards
M. Gregg
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OK. So, 1K ? Or, does the value depend on topology/schematic?
I don't really know what I am doing, but I can figure out the logic and wiring of a switch. 🙂 However, I think I will try hard-wiring this slipstream mode and if it is as good as it is cracked up to be, I'll simply leave well-enough alone.
OK. I have some 1N1200A on hand, is why I asked. I'll get some 1N4007.
In its default state it had no resistors between PIN(s) 4 and the UL tap(s). If this is bad practice then I do want to correct it. Again, it goes back to my question of how to calculate an appropriate R value.
Others have mentioned this, but not provided any instruction on how to actually measure it. If you could do so, it would be a big help. 🙂 Of course, some instruction on how to adjust the bias would be really helpful, too. My instinct is telling me it has something to do with that series resistor...
OK.
Thanks. Will do some reading.
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+100..😀...THWACK..PUFF
As the cones hang out of the speakers..Switch/select when its OFF. Make sure the switch if you fit one has the toggle mounted in earthed metalwork chassis..its switching the B+. I use a rotary switch with a plastic shaft..silver contacts..voltage rating is important.
I use 1K..500V
Regards
M. Gregg
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M. Gregg,
In the EL34 PDF, I assume I should be focusing on the section "Two Valves in Push-Pull" subsection "Distributed load conditions with screen-grid tapping at 43% of primary turns". If this is correct, then how am I to interpret the note:
"* Screen-grid resistor common to both valves"
To me, this sounds like 1 resistor for each pair of valves. I trying hard but can't imagine how I would wire that up.
In the EL34 PDF, I assume I should be focusing on the section "Two Valves in Push-Pull" subsection "Distributed load conditions with screen-grid tapping at 43% of primary turns". If this is correct, then how am I to interpret the note:
"* Screen-grid resistor common to both valves"
To me, this sounds like 1 resistor for each pair of valves. I trying hard but can't imagine how I would wire that up.
As I said, I think I'll skip the switch if I decide I like slipstream.
I assume the lack of instruction on bias measuring and adjustment is a hint that I need to go buy a book and stop asking stupid questions.