Never heard a Sumo, Ampzillia was a star in its day, it would not be today. SAE/BGW/Crown/Phase Linear were poor. We had quite a few thru the shop. One we missed that i would have liked to have heard was the Marantz 500. The Dreadnaught Clarke had the best name and was decent (but shortlive din the marketplace)
All from the early days of big amps. A whole spate of 150-250 w amplifiers.
Few can compete today, and the ones that do are no longer stock.
The best amp of the day, that i heard, was the NAIM NAP250. It wa snot really in the same class as the above as it purposely stuck to a pair of output devices.
The evolution of stuff from one of the Sumo designers is represented by the Shitt amlifiers. And if you remain stuck an email to Jason Stoddard ight gain you some insight.
dave
All from the early days of big amps. A whole spate of 150-250 w amplifiers.
Few can compete today, and the ones that do are no longer stock.
The best amp of the day, that i heard, was the NAIM NAP250. It wa snot really in the same class as the above as it purposely stuck to a pair of output devices.
The evolution of stuff from one of the Sumo designers is represented by the Shitt amlifiers. And if you remain stuck an email to Jason Stoddard ight gain you some insight.
dave
I worked on Marantz 500 amplifiers with Marantz (as a recommended warranty repair facility). Very advanced for the day and even today. I still restore them and have made some improvements to them. I would love to own one.
Many old, high power and famous amplifiers simply did not perform well. We were still learning about how to design for low distortion and what was important. Some of the theories that hampered good design were things like TIM and low feedback. They distracted designers from good sound design practices. Even PCB layout was starting to be understood.
The BGW 750 was a decent amplifier. Sumo and others were not, the Naim wasn't that good either. The Yamaha PC2002 is a very good amplifier, MI product with a home HiFi heart.
One of the best amplifiers I have heard recently is the Bryston 4B3 (cubed). They finally got it right.
Many old, high power and famous amplifiers simply did not perform well. We were still learning about how to design for low distortion and what was important. Some of the theories that hampered good design were things like TIM and low feedback. They distracted designers from good sound design practices. Even PCB layout was starting to be understood.
The BGW 750 was a decent amplifier. Sumo and others were not, the Naim wasn't that good either. The Yamaha PC2002 is a very good amplifier, MI product with a home HiFi heart.
One of the best amplifiers I have heard recently is the Bryston 4B3 (cubed). They finally got it right.
I will disagree. The NAIM 250 was the best amp we found to drive Dayton Wright XG-8. The Marantz 500 did not keep up.
But you are right, a lot of crap high power amplifiers that didn’t sound very good. I put BGW in that camp. Never heard a Sumo.
As to those old amplifiers, Allen Wright said he made good money adding CCSs where they were needed in things like the Phase Linear.
dave
Hi Dave,
yes, that is one of my tricks.
Amplifiers are designed to drive normal loads. When you have a speaker that presents a non-standard load all bets are off. Just because one can has no bearing on those that are designed to drive normal speakers. In fact, I am the one that repaired Mike Wright's Marantz 500 back in the 1980's.
BTW, I am dealing with Mike Wright's (a different Wright that designed preamps and speakers) widow and step son right now.
No matter who designs the speaker, any speaker designed with very low impedance or high reactive components is defective in design. There is zero reason for this situation. One other truth is simply this. Any amplifier driving such a load isn't "happy", and it will not perform to it's normal low distortion. So as a speaker designer, why would you ever design a speaker that causes amplifiers to perform poorly compared to how that same amplifier performs with impedances in the normal range? Does this make any sense to you on any level?
An amplifier that has no protection will tend to drive stupid loads better than one designed intelligently with protection circuits that detect abnormal (normally fault) conditions. Many so-called "high end" amplifiers are in fact designed without protection. Their output stages are no more resilient than other good amplifiers, so no protection is irresponsible and also a cost savings measure. They also review well with guess what? Stupid speaker loads.
The Naim NAP-250 is an average amplifier, nothing special in design. One pair of output transistors, and the protection may be backed off, I haven't tried to study it closely. The outputs have one driver stage off the voltage amp stage. 40 VDC rails. It isn't a bad amplifier, but it is not a great amplifier by any means. It is simple in design like most Naim products. The voltage amp stage is extremely basic in fact. I've worked on many designs that are considerably better, and they sound better. I'm not picking on the Naim, but it is built up in reputation a lot higher than it really is. If it does drive difficult loads without limiting, that proves protection (which it really needs) is backed off. Not a wise design decision, it should have two pairs of outputs minium in that case.
The Marantz 500 drives my PSB Stratus Gold speakers very easily, like the Bryston 4B3 (cubed). Even my Marantz 300DC drives those speakers to the point where the woofer can bottom. All I can say is that the 500 you tried had a problem, it can easily end most speakers. Maybe you had the power limiters switched down (did you notice the front panel controls to limit power on the 500?).
-Chris
yes, that is one of my tricks.
Amplifiers are designed to drive normal loads. When you have a speaker that presents a non-standard load all bets are off. Just because one can has no bearing on those that are designed to drive normal speakers. In fact, I am the one that repaired Mike Wright's Marantz 500 back in the 1980's.
BTW, I am dealing with Mike Wright's (a different Wright that designed preamps and speakers) widow and step son right now.
No matter who designs the speaker, any speaker designed with very low impedance or high reactive components is defective in design. There is zero reason for this situation. One other truth is simply this. Any amplifier driving such a load isn't "happy", and it will not perform to it's normal low distortion. So as a speaker designer, why would you ever design a speaker that causes amplifiers to perform poorly compared to how that same amplifier performs with impedances in the normal range? Does this make any sense to you on any level?
An amplifier that has no protection will tend to drive stupid loads better than one designed intelligently with protection circuits that detect abnormal (normally fault) conditions. Many so-called "high end" amplifiers are in fact designed without protection. Their output stages are no more resilient than other good amplifiers, so no protection is irresponsible and also a cost savings measure. They also review well with guess what? Stupid speaker loads.
The Naim NAP-250 is an average amplifier, nothing special in design. One pair of output transistors, and the protection may be backed off, I haven't tried to study it closely. The outputs have one driver stage off the voltage amp stage. 40 VDC rails. It isn't a bad amplifier, but it is not a great amplifier by any means. It is simple in design like most Naim products. The voltage amp stage is extremely basic in fact. I've worked on many designs that are considerably better, and they sound better. I'm not picking on the Naim, but it is built up in reputation a lot higher than it really is. If it does drive difficult loads without limiting, that proves protection (which it really needs) is backed off. Not a wise design decision, it should have two pairs of outputs minium in that case.
The Marantz 500 drives my PSB Stratus Gold speakers very easily, like the Bryston 4B3 (cubed). Even my Marantz 300DC drives those speakers to the point where the woofer can bottom. All I can say is that the 500 you tried had a problem, it can easily end most speakers. Maybe you had the power limiters switched down (did you notice the front panel controls to limit power on the 500?).
-Chris
Hi Dave,
Okay for execution. Similar amplifiers with better output stages and better voltage amp stages outperformed these easily (Naim amplifiers).
You need high open loop gain and phase margin to support high feedback, which always improves performance of well designed amplifiers. Of course a decent power supply to handle current matters and can hamstring an otherwise great design. This is electronics design and physics, although layout follows rules it appears to look like an art. Some designers naturally do it better than others.
Okay for execution. Similar amplifiers with better output stages and better voltage amp stages outperformed these easily (Naim amplifiers).
You need high open loop gain and phase margin to support high feedback, which always improves performance of well designed amplifiers. Of course a decent power supply to handle current matters and can hamstring an otherwise great design. This is electronics design and physics, although layout follows rules it appears to look like an art. Some designers naturally do it better than others.