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Post subject: Re: Amp Suggestions
Posted: Sun May 18, 2014 8:49 pm
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mhowell wrote:
Do some research? You think I'm pulling stuff off the wall? I've done research.

Here is an example.
Image
Your first two links made the long dis proven assertion about hard vs soft clipping. We can plainly see that tube amps are quite capable of hard clipping. It is also relatively easy to get SS to produce soft clipping?

The third link was a good source in 1994. Seriously? You don't think modeling has gotten any better in the last 20 years?

I really didn't intend to launch a debate that I'm not really qualified to pursue. I am not a professional musician so please take anything (everything?) I say with a grain of salt. I have also never stated that modeling or any other type of SS is better, or worse, than tubes. I have said that for me, as a non professional, I cannot justify the expense of a tube amp over a good SS amp because I honestly do not hear any significant difference.

I try to hear the difference. I really do. I thought I heard it once but Arjay said, "No. That's not it".

I respect you very much bluesky so please take the last word.


Since you neglected to do so, here is the schematic for the amp you are referencing:

Image

Please provide the measurement points and the conditions under which the measurements were taken. Was this "test" done with a properly biased and working amplifier with good tubes, or was the amp "sick" and these were taken as part of the diagnostic tests? Without that information the two charts you provided are meaningless.

I never said that a tube amp will not hard clip. Any amp will clip once the output voltage swing becomes great enough that the power supply can't support it. The difference between tube and solid state amps is the point at which hard clipping occurs and the harmonics generated as the output stage overloads. In a solid start amp, hard clipping occurs very soon after the rated power at the specified distortion (usually less than 1% THD) is exceeded. A tube amp on the other hand is typically rated at 3% to 5% THD (or higher) at maximum output before hard clipping occurs. Before hard clipping occurs, a push-pull amp will generated mostly odd harmonics (Even harmonics are canceled out for the most part, although some make it through. Keep in mind that a single ended power amp or a preamp, is mostly generating even harmonics when it distorts.). Because of the way tube and SS amps are rated, a tube amp will begin to overload and generate many odd harmonics before hard clipping occurs while a SS amp will go bang into hard clipping from a clean signal. Once into hard clipping, both amps will generate both odd and even harmonics which can sound quite nasty.

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Last edited by bluesky636 on Sun May 18, 2014 9:05 pm, edited 1 time in total.

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Post subject: Re: Amp Suggestions
Posted: Sun May 18, 2014 9:03 pm
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Joined: Wed May 25, 2011 12:45 pm
Posts: 1169
bluesky636 wrote:
mhowell wrote:
Do some research? You think I'm pulling stuff off the wall? I've done research.

Here is an example.
Image
Your first two links made the long dis proven assertion about hard vs soft clipping. We can plainly see that tube amps are quite capable of hard clipping. It is also relatively easy to get SS to produce soft clipping?

The third link was a good source in 1994. Seriously? You don't think modeling has gotten any better in the last 20 years?

I really didn't intend to launch a debate that I'm not really qualified to pursue. I am not a professional musician so please take anything (everything?) I say with a grain of salt. I have also never stated that modeling or any other type of SS is better, or worse, than tubes. I have said that for me, as a non professional, I cannot justify the expense of a tube amp over a good SS amp because I honestly do not hear any significant difference.

I try to hear the difference. I really do. I thought I heard it once but Arjay said, "No. That's not it".

I respect you very much bluesky so please take the last word.


Since you neglected to do so, here is the schematic for the amp you are referencing:

Image

Please provide the measurement points and the conditions under which the measurements were taken. Was this "test" done with a properly biased and working amplifier with good tubes, or was the amp "sick" and these were taken as part of the diagnostic tests? Without that information the two charts you provided are meaningless.

Don't take my word for anything. Take measurements at the output stage of your 5f6a and see if you get similar results.

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Post subject: Re: Amp Suggestions
Posted: Sun May 18, 2014 9:17 pm
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Rock Star
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Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
mhowell wrote:
Don't take my word for anything. Take measurements at the output stage of your 5f6a and see if you get similar results.


Please see my edited post above.

Sorry, no. Without knowing the conditions that created the graphs you provided, there is no frame of reference for comparison to any other amp. I have no intention of driving any of my amps like that without having a known reference to compare them to. Just looking at the feedback circuit around the power stage tells me that the Univox amp was designed so that the power stage will go into heavy overload and sooner than the 5F6A Bassman. A quick calculation shows that the Univox loop gain is about 75% of the open loop gain whereas the Bassman is about 55% of the open loop gain. My Wrecking Ball (Trainwreck Express close) loop gain is about 66% of the open loop gain.

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Post subject: Re: Amp Suggestions
Posted: Sun May 18, 2014 9:41 pm
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bluesky636 wrote:
mhowell wrote:
Don't take my word for anything. Take measurements at the output stage of your 5f6a and see if you get similar results.


Please see my edited post above.

Sorry, no. Without knowing the conditions that created the graphs you provided, there is no frame of reference for comparison to any other amp. I have no intention of driving any of my amps like that without having a known reference to compare them to. Just looking at the feedback circuit around the power stage tells me that the Univox amp was designed so that the power stage will go into heavy overload and sooner than the 5F6A Bassman. A quick calculation shows that the Univox loop gain is about 75% of the open loop gain whereas the Bassman is about 55% of the open loop gain. My Wrecking Ball (Trainwreck Express close) loop gain is about 66% of the open loop gain.

I don't think you have to drive your amps any more than it takes to see the clipping characteristics. Would that be more stressful than when it is played at volume? If so, then forget it.

I only mentioned it because of the links you referenced. Your edited comments are more valid than your references. However, you demand all kinds of details from me but you only make assertions.

Despite all this my ears fail to hear the difference between the two technologies.

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Post subject: Re: Amp Suggestions
Posted: Sun May 18, 2014 9:57 pm
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Rock Star
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Joined: Mon Apr 05, 2010 2:37 pm
Posts: 8708
Location: Natural Bridge, Virginia
mhowell wrote:
However, you demand all kinds of details from me but you only make assertions.


You posted a graph with zero context. You didn't even have the courtesy to provide a schematic for the amp you were referencing. I went and found it and when I asked you a few simple questions about the graphs you threw it back at me. Sorry. You were the one making assertions as to what the graphs claimed to be showing with no information to back it up. I then responded with an evaluation of some significant differences between the amp you referenced and two other amps with which I am intimately familiar with. If you want to understand how I made that evaluation, here you go:

http://ampbooks.com/home/amplifier-calc ... /feedback/

I only did a rough calculation. If you want to do a detailed analysis, feel free.

I'm done with this subject and stand behind my "assertions".

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Post subject: Re: Amp Suggestions
Posted: Sun May 18, 2014 10:08 pm
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Joined: Wed May 25, 2011 12:45 pm
Posts: 1169
bluesky636 wrote:
mhowell wrote:
However, you demand all kinds of details from me but you only make assertions.


You posted a graph with zero context. You didn't even have the courtesy to provide a schematic for the amp you were referencing. I went and found it and when I asked you a few simple questions about the graphs you threw it back at me. Sorry. You were the one making assertions as to what the graphs claimed to be showing with no information to back it up. I then responded with an evaluation of some significant differences between the amp you referenced and two other amps with which I am intimately familiar with. If you want to understand how I made that evaluation, here you go:

http://ampbooks.com/home/amplifier-calc ... /feedback/

I only did a rough calculation. If you want to do a detailed analysis, feel free.

I'm done with this subject and stand behind my "assertions".

Harumph! Harumph! :roll:

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In my opinion Leo Fender had essentially perfected the guitar amplifier by 1964.


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Post subject: Re: Amp Suggestions
Posted: Sun May 18, 2014 10:22 pm
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Posts: 560
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bluesky636 wrote:
As far as modeling and solid state go, have you ever seen a modeling amp with a solid state amp model? Other than the basic amp sound, I haven't.


I only know of one, and that is the Roland Cube Amp series that has an emulation of it's Roland Jazz Chorus Amp - ("JC Clean" is the emulation name I think). When I owned that amp I don't remember anything outstanding about that setting. To me my tube amp sounds better at this stage in my life.

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Post subject: Re: Amp Suggestions
Posted: Sun May 18, 2014 11:01 pm
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......Meanwhile the OP is likely still clueless as to which amp (employing whichever technology) would be best for his particular circumstance.

:roll:

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: Amp Suggestions
Posted: Mon May 19, 2014 7:52 am
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Retroverbial wrote:
......Meanwhile the OP is likely still clueless as to which amp (employing whichever technology) would be best for his particular circumstance.

:roll:

Arjay


He should just get a Peavey Bandit and be done with it. Or just plug straight in to the board. Just a dry, sterile, direct sound. No one listens to the guitar part anyway, except for other guitarists, and they will find something wrong with his amp no matter what he gets. Just plug straight in and move on dude. There are other things to worry about in life.


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Post subject: Re: Amp Suggestions
Posted: Mon May 19, 2014 9:40 am
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spaceape wrote:
Retroverbial wrote:
......Meanwhile the OP is likely still clueless as to which amp (employing whichever technology) would be best for his particular circumstance.

:roll:

Arjay


He should just get a Peavey Bandit and be done with it. Or just plug straight in to the board. Just a dry, sterile, direct sound. No one listens to the guitar part anyway, except for other guitarists, and they will find something wrong with his amp no matter what he gets. Just plug straight in and move on dude. There are other things to worry about in life.

Did that in a church once. I came in with my amp and I'm looking for an outlet to plug my amp into. The music director comes over, grabs my guitar cable and plugs it into 1/4" jack on the floor. "Well, OK", I thought.

No amp, no effects, just a straight dry signal. On top of that I was barely in the monitor.

The music director asked me if I would be willing to play bass from then on.

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In my opinion Leo Fender had essentially perfected the guitar amplifier by 1964.


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Post subject: Re: Amp Suggestions
Posted: Mon May 19, 2014 9:45 am
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Joined: Fri May 16, 2014 10:32 am
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mhowell wrote:
spaceape wrote:
Retroverbial wrote:
......Meanwhile the OP is likely still clueless as to which amp (employing whichever technology) would be best for his particular circumstance.

:roll:

Arjay


He should just get a Peavey Bandit and be done with it. Or just plug straight in to the board. Just a dry, sterile, direct sound. No one listens to the guitar part anyway, except for other guitarists, and they will find something wrong with his amp no matter what he gets. Just plug straight in and move on dude. There are other things to worry about in life.

Did that in a church once. I came in with my amp and I'm looking for an outlet to plug my amp into. The music director comes over, grabs my guitar cable and plugs it into 1/4" jack on the floor. "Well, OK", I thought.

No amp, no effects, just a straight dry signal. On top of that I was barely in the monitor.

The music director asked me if I would be willing to play bass from then on.


See, the dry direct tone got you a permanent gig. It's underrated and totally free.


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