
better preamp ic than 4580/5532?
yes, what you are saying is also true. neither are exact descriptions. never the less, class A or single ended designs handle the entire waveform. push-pull designs have output devices in pairs with each half of the pair handling half the waveform.Immanuel wrote:Gary, this is wrong. What you are describing is single ended or unballanced design versus push/pull or ballanced design.garyb wrote:in class A one device handles top and bottom of the waveform. in class B and AB, one device has the top(push) and the other the bottom(pull). this is more efficient(louder with less power required), but not as "musical" sounding.
Class A is about consuming full power all the time. You can say, that the PSU feeds the cirquit with full power all the time, where as in the other designs, the cirquit has to draw the needed amount of power out of the PSU.
http://www.duncanamps.com/technical/ampclasses.html
http://www.pcmag.com/encyclopedia_term/ ... 350,00.asp
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I found that clearly some brands of tubes sound much better than other brands. I don't think you can say that about transistors. When you say transistors can sound like tubes, it is a general statement. Which tubes do they sound like? I am not buying it. Let's just say that in theory transistors can sound good and some do. Maybe it is a matter of taste as well.
Gary - as I see it, you are still off. Class A does not have to be single ended. Try to find a high end mic pre which is not both class a and push/pull (ballanced). Also, single ended does not have to be class A.garyb wrote:yes, what you are saying is also true. neither are exact descriptions. never the less, class A or single ended designs handle the entire waveform. push-pull designs have output devices in pairs with each half of the pair handling half the waveform.
Apart from tonal qualities, as I've already outlined, with tubes the different knee introducing into saturation state allows for sound settings having only high dynamic peaks been saturated. that's not easy to achieve using transistors.
... I've found out TL072 is JFet based...
About the 4562, as far as i can get from data sheets: it has the same pin layout of 4580, has similar THD, looks like it has more gain...
... I've found out TL072 is JFet based...
About the 4562, as far as i can get from data sheets: it has the same pin layout of 4580, has similar THD, looks like it has more gain...
it's a matter of fact that neither transistors nor tubes do sound at allbraincell wrote:I found that clearly some brands of tubes sound much better than other brands. I don't think you can say that about transistors. When you say transistors can sound like tubes, it is a general statement. Which tubes do they sound like? I am not buying it. Let's just say that in theory transistors can sound good and some do. Maybe it is a matter of taste as well.
what sounds is the device, built from active and passive elements according to a specific design.
for some sounds someone wants it transparent and crystal clear, for other sounds another one prefers a muddy tone or even a disharmonic distortion.
A tube based circuit design is as good or bad as a semiconductor one by default, but tubes have the visual mystery advantage (and of course the vintage touch), though Germanium transistors recently seem to catch up a bit...
Most of that stuff is just marketing blurb anyway, as has been mentioned already.
My request for another circuit design than the (so-called) 'usual' 4580/5532/TL72/TL82 layout was based on the impression that for a very specific application there are better ways - whatever they may be based on.
I didn't have a look into the Avalon U5 or the Tecamp Puma bass amp, but these units have exactly that extra definition I miss.
And for those swearing on tubes I suggest to listen particularily close to the latter amp. You won't trust your ears that it's a tubeless design, once you start turning that 'Character' dial to the right...

cheers, Tom
find me a class A amp that IS push/pull. balanced is not push/pull. balanced has the ground isolated from the audio positive and negative signals. class A can be balanced or unbalanced on it's input. push/pull is class B or it's variants(AB, H etc.) single-ended refers to the fact that the whole waveform is handled but each output device. only one is required for the entire waveform with class A. push/pull requires pairs of devices. when one is on the other is off and vice versa, each handling half the waveform.Immanuel wrote:Gary - as I see it, you are still off. Class A does not have to be single ended. Try to find a high end mic pre which is not both class a and push/pull (ballanced). Also, single ended does not have to be class A.garyb wrote:yes, what you are saying is also true. neither are exact descriptions. never the less, class A or single ended designs handle the entire waveform. push-pull designs have output devices in pairs with each half of the pair handling half the waveform.
from the duncan link posted earlier:
If we now superimpose a signal on the grid voltage, the anode current will vary up and down in sypathy with the grid voltage, hence the "Out" waveform.
As the title suggests, this is "Class A". The distinguishing feature of class A is that the valve is conducting current at all times. Note the the "Out" current never drops down to the zero line at any time.
Some output stages are class A (such as the Vox AC-30), and all preamp sections are class A. If you want to check out a circuit diagram with a class A output stage, you can download the circuit of my Blues-112 combo. Note that you will need Adobe Acrobat installed to make sense of it!
OK, that's class A out of the way. What about class B? In the diagram on the right, we have set the bias point to where the valve has almost stopped conducting.
Note that the input signal is a lot larger now in order to drive the valve hard enough. Also, the output current is only for half of the waveform.
To make any use of this, we have to have a "push-pull" output stage which employs two valves (or two banks of valves) so that each side amplifies each half of the waveform. While the first output valve provides the output current as shown on the right, the second valve fills in the gap which follows it.
the SSM 2019 (mentioned in the quote about the XITE preamps) is by Analog DevicesCochise wrote:Some time ago I was reading about good OpAmps from Analog Devices....

cheers, Tomenumeratus wrote:Good guess - the XITE preamps actually have SSM 2019 input amplifiers.Strattosphere wrote: ...Hopefully they'll use something like Burr Brown INA137s or THAT 1512 chips for the preamps.
Stratt