I don't know if you understand the phrase "You've got 2 chances"
Well to put it plainly. You've got 2 chances.
Well to put it plainly. You've got 2 chances.
J2 to drive Edgar Seismic subs - feedback question
I have mocked this up and the amp does just fine.
I am using two and want to retain the character of the J2 from bottom to the top.
My (goofy, I do not doubt) question is: I would like to get some extra gain, around 5 dB, from the amp to be used for the bass. I do not want to add a gain stage preferring to use a Broskie tube based crossover with no gain.cathode followers using plus and negative voltage rails. ( OK, that was the premise not the question)
What would happen if one was to lower the feedback (of course, I have no idea how much is being used). Would 5 dB less make this a zero feedback amplifier? Somehow I figure there is more than that. Would reducing feedback in an amplifer used for low bass only be OK or would one be disappointed by the result?
I feel confident with instruction I could make the modification without making a mess.
I hope this question does not sound like a fishing expedition even though I figure those cleverer than I could figure out where the feedback loop is without asking any questions.
Just trying to get by without adding a gain stage to equalize output.
Can anyone help me or am I simply too far gone?
Thanks,
I have mocked this up and the amp does just fine.
I am using two and want to retain the character of the J2 from bottom to the top.
My (goofy, I do not doubt) question is: I would like to get some extra gain, around 5 dB, from the amp to be used for the bass. I do not want to add a gain stage preferring to use a Broskie tube based crossover with no gain.cathode followers using plus and negative voltage rails. ( OK, that was the premise not the question)
What would happen if one was to lower the feedback (of course, I have no idea how much is being used). Would 5 dB less make this a zero feedback amplifier? Somehow I figure there is more than that. Would reducing feedback in an amplifer used for low bass only be OK or would one be disappointed by the result?
I feel confident with instruction I could make the modification without making a mess.
I hope this question does not sound like a fishing expedition even though I figure those cleverer than I could figure out where the feedback loop is without asking any questions.
Just trying to get by without adding a gain stage to equalize output.
Can anyone help me or am I simply too far gone?
Thanks,
just alter ratio of feedback resistors ( two of them - usual stuff as in any Aleph )
now their ratio is 10 (20db gain)
alter that to 17,5 (25db gain)
then listen what your ears will tell ya
now their ratio is 10 (20db gain)
alter that to 17,5 (25db gain)
then listen what your ears will tell ya
Thanks for the encouragement
Now to see if I am brave enough to screw around with the amplifier.
A part of me was hoping I would be told DON'T EVEN TRY!
As always, THANKS for your comments and help,
Now to see if I am brave enough to screw around with the amplifier.
A part of me was hoping I would be told DON'T EVEN TRY!
As always, THANKS for your comments and help,
What's the worst that could happen?
Other than complete disappointment? I would not know.
It is obvious I have been enjoying this amp hence my acquiring a second one.
Don't want to harm it most assuredly.
The more I think about it the less damping from less feedback is probably reason enough to let it alone and just add a low-gain stage before the crossover. My mocked up experiment so far tells me the amp has control over an eighteen inch woofer. Lessening the FB might be asking too much.
I have been playing it as loud as I ever would with no sounds of obvious distortion. I guess it is true that a single ended amp does sound more powerful than its power rating would indicate? The SEISMICs are efficient within the world of subwoofers. I am not going for DISCO sound pressure which helps.
The amp does not produce the hard thump of the toy amps I had used before (the NHT as suggested by Edgar ten years ago and the useless RECKHORN amps two of which failed driving this easy load. CAVEAT EMPTOR on those things; both had power supply capacitor failures) There is a superior blending only to be expected when using the same amplifiers. Even the first two octaves are revealing of this necessary quality I have found. Always suspected but did not want to find out - if one could get by with a three hundred dollars "plate" amp and get a musical sound it would be nice, wouldn't it?
Compormise is the way of the audiophile, isn't it?
Bye,
Other than complete disappointment? I would not know.
It is obvious I have been enjoying this amp hence my acquiring a second one.
Don't want to harm it most assuredly.
The more I think about it the less damping from less feedback is probably reason enough to let it alone and just add a low-gain stage before the crossover. My mocked up experiment so far tells me the amp has control over an eighteen inch woofer. Lessening the FB might be asking too much.
I have been playing it as loud as I ever would with no sounds of obvious distortion. I guess it is true that a single ended amp does sound more powerful than its power rating would indicate? The SEISMICs are efficient within the world of subwoofers. I am not going for DISCO sound pressure which helps.
The amp does not produce the hard thump of the toy amps I had used before (the NHT as suggested by Edgar ten years ago and the useless RECKHORN amps two of which failed driving this easy load. CAVEAT EMPTOR on those things; both had power supply capacitor failures) There is a superior blending only to be expected when using the same amplifiers. Even the first two octaves are revealing of this necessary quality I have found. Always suspected but did not want to find out - if one could get by with a three hundred dollars "plate" amp and get a musical sound it would be nice, wouldn't it?
Compormise is the way of the audiophile, isn't it?
Bye,
certainly weirdest plate amp-money can buy
Papa just said that you are free to try ; disappointments are also steps in learning process , but you certainly have more than fair chances to be pleased with result .
in any case - having two of them ( respect for respect !) , you are always free to move one to bedroom system , and make one from scratch - with increased gain , and two pairs of SS outputs - to increase current capacity and compensate gain ( meaning - increase OLG , while increasing CLG , so overall feedback stays the same ........ if this is important for your better sleep )
Papa just said that you are free to try ; disappointments are also steps in learning process , but you certainly have more than fair chances to be pleased with result .
in any case - having two of them ( respect for respect !) , you are always free to move one to bedroom system
, and make one from scratch - with increased gain , and two pairs of SS outputs - to increase current capacity and compensate gain ( meaning - increase OLG , while increasing CLG , so overall feedback stays the same ........ if this is important for your better sleep )
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sending to Mighty ZM for proper disposal ?
ZM,
I think you mentioned somewhere you have built a Babelfish J2?...and circuit is still being kept away from the greedyboyz. I also have a version drawn up which I've also shown and promised Papa to keep a lid on. Do you want to swap circuits and compare and learn(at least for me)?