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,
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)?