I am considering building a SE amp using the 50EH5 tube, for the output transformer I am going to use an Edcor, is it worth spending the extra money to buy the GXSE over the XSE? Would I be able to hear the difference between the two?
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nikon f,
This amp will be for Hi Fi?
Or for a Guitar practice amp?
How will you operate the tube?
Pentode operation? Yes, probably. Most power. for Hi Fi, Need negative feedback.
Ultra Linear operation? Use the UL tap on the transformer. Medium power. Application determines whether negative feedback is needed or not.
Triode Wired operation? Lowest power, but not needing negative feedback.
Suppose you use the data sheet example:
Pentode operation, 110V plate and 115V screen, and 42mA
plate, 11.5mA screen, and 8000 Ohm plate load.
You will get 1.4 Watts at mid frequencies (a little less power, perhaps 1.1 Watt, because of the transformer insertion loss).
This output tube would normally be used for a table radio, or small TV, not a Hi Fi setup.
I bet the radio/TV output transformer was smaller than either of the Edcore models.
And neither one of those would have an 8 inch woofer plus a tweeter.
For Hi Fi,
The transformer needs to have enough primary inductance, and enough laminations to keep it from saturation at low frequencies.
I do not know those models, but the inductance should be listed, and the weight should be listed too.
Especially in Pentode mode, you will not have very good frequency response without using negative feedback.
It is important that the transformer not saturate, negative feedback makes that worse.
Well for some Guitar grunge, you may want saturation.
Another factor is whether or not you will want to use that output transformer again in another amplifier, that may require the more expensive one.
Just my 2 cents.
Wow, do you still shoot film with the Nikon f?
I use digital bodies, and old manual focus lenses with lens adapters, I have several Nikkor lenses.
But I need to get out my medium format camera and shoot some 120 B&W film, then mail to Ilford for silver prints.
This amp will be for Hi Fi?
Or for a Guitar practice amp?
How will you operate the tube?
Pentode operation? Yes, probably. Most power. for Hi Fi, Need negative feedback.
Ultra Linear operation? Use the UL tap on the transformer. Medium power. Application determines whether negative feedback is needed or not.
Triode Wired operation? Lowest power, but not needing negative feedback.
Suppose you use the data sheet example:
Pentode operation, 110V plate and 115V screen, and 42mA
plate, 11.5mA screen, and 8000 Ohm plate load.
You will get 1.4 Watts at mid frequencies (a little less power, perhaps 1.1 Watt, because of the transformer insertion loss).
This output tube would normally be used for a table radio, or small TV, not a Hi Fi setup.
I bet the radio/TV output transformer was smaller than either of the Edcore models.
And neither one of those would have an 8 inch woofer plus a tweeter.
For Hi Fi,
The transformer needs to have enough primary inductance, and enough laminations to keep it from saturation at low frequencies.
I do not know those models, but the inductance should be listed, and the weight should be listed too.
Especially in Pentode mode, you will not have very good frequency response without using negative feedback.
It is important that the transformer not saturate, negative feedback makes that worse.
Well for some Guitar grunge, you may want saturation.
Another factor is whether or not you will want to use that output transformer again in another amplifier, that may require the more expensive one.
Just my 2 cents.
Wow, do you still shoot film with the Nikon f?
I use digital bodies, and old manual focus lenses with lens adapters, I have several Nikkor lenses.
But I need to get out my medium format camera and shoot some 120 B&W film, then mail to Ilford for silver prints.
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50EH5 Single-Ended (SE) DIY Tube Amplifier Project
Here is a the amp that I am considering schematics figure 3 and 4. I do not know if it's triode or pentode.
Yes I still shoot film with a Nikon F, Leicaflex SL, Leica M3, Leica IIIF and a Minolta SR-1S. I am a retired Industrial/Scientific Photographer, BFA from Brooks Institute of Photography.
Here is a the amp that I am considering schematics figure 3 and 4. I do not know if it's triode or pentode.
Yes I still shoot film with a Nikon F, Leicaflex SL, Leica M3, Leica IIIF and a Minolta SR-1S. I am a retired Industrial/Scientific Photographer, BFA from Brooks Institute of Photography.
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I hope you have most of the parts for the amp.
Could be fun to build.
But none of those amps has very good performance . . . gain, distortion, frequency response.
And all the schematics show pentode operation without any negative feedback.
Realistically, only the schematic with the 12AX7 can properly utilize global negative feedback, and even that could be tricky.
Again, what would you use the amp for?
Hi Fi, like a computer desk amp?
Or for a Guitar practice amp?
I have some nice Minolta manual focus lenses, including a 50mm f3.5 macro and a 28mm f3.5 wide angle with the Very large front glass.
Could be fun to build.
But none of those amps has very good performance . . . gain, distortion, frequency response.
And all the schematics show pentode operation without any negative feedback.
Realistically, only the schematic with the 12AX7 can properly utilize global negative feedback, and even that could be tricky.
Again, what would you use the amp for?
Hi Fi, like a computer desk amp?
Or for a Guitar practice amp?
I have some nice Minolta manual focus lenses, including a 50mm f3.5 macro and a 28mm f3.5 wide angle with the Very large front glass.
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It's more of a fun amp for desk top use with a pair of Fostex 103en bass reflex or Braun L200 speakers. I have all the parts except for the output transformers.
For my Minolta i have the 28mm f3.5(5mm filter), 55mm f1.7, 100mm f3.5 and 135mm f2.8 all MC rocker lenses.
For my Minolta i have the 28mm f3.5(5mm filter), 55mm f1.7, 100mm f3.5 and 135mm f2.8 all MC rocker lenses.
Hi Nikon F
I've seen a discussion on this topic at DIY Audio Projects Forum • 6CY7 Stereo Amp
Looks like you might loose some performance at lower frequencies.
I've seen a discussion on this topic at DIY Audio Projects Forum • 6CY7 Stereo Amp
Looks like you might loose some performance at lower frequencies.