Man , you have no ideea how wrong you are....
The Zeck amp is 1000 light years ahead of that Yamaha, but because it's optimized to drive difficult low impedance loads at high powers you can't see it performing the way it can at low powers if it would be optimized for that .That's the case for almost all PA amplifiers actually..
You didn't even try to make the gain higher and that tells you're in the wrong cathegory for me to even adress...Zeck is using video transistors before the power stage...
When you're mature enough to understand what amps those Zecks are:
1.Make the gain higher and lower the compensation capacitance in the input differential .
2.Remove 4 or even 5 pairs of final transistors , leaving just one , maximum two at work and run that amp at the same power as yamaha! You'll understand easier this way what driving a BE capacitance means for an amp's slew rate.
If possible change T17, T18 with faster medium power transistors like those used in Yamaha(KD600...)
3.Tell me how wrong I was !
The Zeck amp is 1000 light years ahead of that Yamaha, but because it's optimized to drive difficult low impedance loads at high powers you can't see it performing the way it can at low powers if it would be optimized for that .That's the case for almost all PA amplifiers actually..
You didn't even try to make the gain higher and that tells you're in the wrong cathegory for me to even adress...Zeck is using video transistors before the power stage...
When you're mature enough to understand what amps those Zecks are:
1.Make the gain higher and lower the compensation capacitance in the input differential .
2.Remove 4 or even 5 pairs of final transistors , leaving just one , maximum two at work and run that amp at the same power as yamaha! You'll understand easier this way what driving a BE capacitance means for an amp's slew rate.
If possible change T17, T18 with faster medium power transistors like those used in Yamaha(KD600...)
3.Tell me how wrong I was !
Hy, I did listen to this amp with correct gain alot with Mollys preamp... I had those Pioneers on, I had 15" woofers with horns, 18" woofers with horns, 12" double voice coil sub....
It does sound good and very dynamic.
I will make gain modifications as you suggested so I can loose the preamp, but I wont modify the output as I still want to use it for 18" woofers. This is what Zeck was made for and it never disappointed me... loud and as much bass as you want without clipping. Also it wont produce buzz or static no mather what.
18 inch woofers with horns should be able to move your furniture around the house at 100 watts ... unless you own the Versaille Palace..that's something I didn't consider cause usually the King of France doesn't talk to me on diyaudio... 2 pairs of power trz are good enough for that. The upper part of the G class stage shouldn't even work below 120 watts/4ohms...3EF class AB or G PA amplifiers differ essentially from hi-fi amps by only one pair of transistors , the driver transistors for the final stage.As the final stage has many trz in parallel , they need high power transistors for the drive stage.Power trz have low FT and high BE capacitance so you can't drive fast the power stage in high power amplifiers.The fastest high power trz have half or three times lower FT than fast medium power trz used in tipycal hi-fi amps (100...150watts).So most PA amps can be made faster and better rendering the mid-high frequency range by removing unnecessary power stage transistors .In class G amps it's even less critical to make modiffications cause you can safely remove the upper stage alltogether and that means that you don't have to modify the power stage irreversebly.
Your Yamaha just have less, but faster drive and final transistors, but the input stage is inferior to Zeck's .
Your Yamaha just have less, but faster drive and final transistors, but the input stage is inferior to Zeck's .
I don't use those woofers in the house, as much as I would like to, that would ruin relationship with neighbours for sure...
I use them outside for bithdays and such (at the remote location). I drive them just bellow the clipping often, so I believe I need all that power.
It's nice to have the information you gave me tho, I had no idea that such modification can be done to PA amp and if I come across something at least half good for low price, I will definately take a chance and try it out for myself.
