Geeky history of solid state amps question.

[Twincam]

I'm just wondering what the first generation of solid state amps like?

Same question about the first gen of class D amps.
No reason to ask other than I'm a bit geeky.

[r16ktx]

Wouldn't the 1st gen use valves as solid state means 'no moving parts'? Do I get points for being geeky AND pedantic? ;-)

[Twincam]

[quote name='r16ktx' timestamp='1461524070' post='3035425']
Wouldn't the 1st gen use valves as solid state means 'no moving parts'? Do I get points for being geeky AND pedantic? ;-)
[/quote]

No!

Although the first gen transistor based amps were apparently slightly tweaked valve amp designs. They didn't work so well.

[taunton-hobbit]

I had a couple of Vortexion monoblock 100watt amps in about 1968 - they were transistor & billed as indestructible. Much to Vortexions embarrassment, one blew up on its first gig...oops....they fixed it, took the boast off their publicity and I still had them in a workshop (& working) in 2003.......
probably one of the first solid state high power amps.

[Bill Fitzmaurice]

The first SS amps were quite horrid, especially where noise is concerned.

[Twincam]

[quote name='taunton-hobbit' timestamp='1461527115' post='3035469']
I had a couple of Vortexion monoblock 100watt amps in about 1968 - they were transistor & billed as indestructible. Much to Vortexions embarrassment, one blew up on its first gig...oops....they fixed it, took the boast off their publicity and I still had them in a workshop (& working) in 2003.......
probably one of the first solid state high power amps.


[/quote]

Did it have heft?

[Chienmortbb]

[quote name='Bill Fitzmaurice' timestamp='1461527227' post='3035471']
The first SS amps were quite horrid, especially where noise is concerned.
[/quote]Our Guitarist in the late 60s decided a Vox T60 would be netter than an AC30. It was basically one channel of a (not very good) HiFi amp. Noisy as hell and no real power. It and its ilk are probably why SS amos have a bad name to this day.

On the other hand, the HH 100W amps that came a few years later were awesome (although still a little noisy) Still got two of their 100W bass amps.

[taunton-hobbit]

For their time, the noise/distortion was negligible, I was using them flat-out as a fill in a soul disco club (I had a 200watt OrangeMatamp for main grunt).
Heft was, in retrospect, a bit lacking.....but they did the job for years without complaint (& I used them on mobile gigs).

[Dan Dare]

Early ss amps used large amounts of negative feedback to give acceptable distortion results. That was reckoned to give them their flat lifeless weak sound.

[Twincam]

[quote name='Chienmortbb' timestamp='1461528386' post='3035487']
Our Guitarist in the late 60s decided a Vox T60 would be netter than an AC30. It was basically one channel of a (not very good) HiFi amp. Noisy as hell and no real power. It and its ilk are probably why SS amos have a bad name to this day.

On the other hand, the HH 100W amps that came a few years later were awesome (although still a little noisy) Still got two of their 100W bass amps.
[/quote]

I've read the t60 bass amp often overheated as it was always producing sound in a frequency above what humans could hear, so it was being driven well beyond its specs and would go into melt down.

[Phil Starr]

Most of the first generation SS amps used the 2N3055 transistors as output devices. These were cheap and handled quite a lot of power but were limited to 70volts and only developed just over 60W into 8ohms.

Like all bipolar output transistors they were liable to breaking down very quickly when hot and many did. Protection circuits were developed but many of these sounded awful or even shut the amp down when triggered. A lot of the early amps also oscillated at high frequencies which didn't help either.

A lot of early class AB designs also suffered from a lot of artefacts (distortion) at the point where the output transistors crossed over. More consistent component manufacture and the adoption of split rail power supplies helped.

When the HH amps came along they used the superior 2N3773 which ran at 100V and better protection circuitry was developed. The price of components also fell rapidly and for bass and PA a load of output transistors were run in parallel increasing the power handling.

Is that geeky enough?

[Chienmortbb]

[quote name='Phil Starr' timestamp='1461619104' post='3036253']
Most of the first generation SS amps used the 2N3055 transistors as output devices. These were cheap and handled quite a lot of power but were limited to 70volts and only developed just over 60W into 8ohms.

Like all bipolar output transistors they were liable to breaking down very quickly when hot and many did. Protection circuits were developed but many of these sounded awful or even shut the amp down when triggered. A lot of the early amps also oscillated at high frequencies which didn't help either.

A lot of early class AB designs also suffered from a lot of artefacts (distortion) at the point where the output transistors crossed over. More consistent component manufacture and the adoption of split rail power supplies helped.

When the HH amps came along they used the superior 2N3773 which ran at 100V and better protection circuitry was developed. The price of components also fell rapidly and for bass and PA a load of output transistors were run in parallel increasing the power handling.

Is that geeky enough?

[/quote]Phil the first solid state amps like the Vox T60 were not even using 2N3055 transistors. Of course the real boost in power came with MOSFET. They could be paralleled up to get more current as in the latter HH professional power amps, Trace, Ashdown and Ampeg among others used this technique.

[chris_b]

Early solid state amps sounded awful.

What you played was more important than how you sounded and for that reason (and the fact that they were very cheap on the second hand market) gigging musicians did use them.

The first good sounding solid state amp I heard was my Dynacord combo that I bought in the mid 80's.

[stevie]

http://www.ssguitar.com/index.php?topic=469.0

[luckydog]

I briefly owned a vox T60 head back in the day - diabolical in most respects I recall, not least there was a permanent waterfall in the background by way of noise !

I also briefly owned a HH VS 100 watt combo, which sounded great and is rightly now a classic and super loud. Likes of Wilko etc, classic sound. This was prob made about 10 years after the Vox T60 and things had moved on a long long way.

The Vox T60 used germanium transistors throughout, I think it dated from the early 60s, though it was the 70s before I encountered it. BTW, nothing as recent as 2n3055s, output trannies were OC28s ! And yes, they used to fail !

The HH VS was early days of power mosFETs IIRC - things had moved on a long way soundwise in 10 years or so.......

LD

[Beer of the Bass]

Regarding the earliest amps being made with germanium transistors, I think the Burns Orbit was though I don't know about the others. The inconsistency of germanium transistors must have been a real issue with those - I've played around with them in fuzz boxes and you have to test the gain and leakage of each individual transistor as they're all different!
As a slight aside I was reading about Walter Woods amps yesterday, which would appear to be the first use of class-D and SMPS in musical instrument amps. I find it interesting that those are still revered for their sound today even though the technology was in its infancy at the time.

Edited April 26, 2016 by Beer of the Bass

[Twincam]

This thread is now suitably geeky

I wouldn't mind trying some old equipment just for curiosity's sake. Some must still be running somewhere.

[luckydog]

With vintage gear there is the benefit of hindsight, and gear that earns a reputation and survives the test of time has already been proven to have some merit. Unfortunately none of the early tranny amps have passed that test, I venture because they sound awful.........

What did Chumbawamba say "Nothing is completely useless, it can always serve as a bad example......." ?

LD

[chriswareham]

Anyone know what Acoustic Control Corporation did to make their solid state amps sound so good compared to other SS models of the day? I think mine runs internally at 70v which suggests limitations similar to the early tranny amps, but it's very loud, with lots of bottom end and not much noise.

[Twincam]

[quote name='chriswareham' timestamp='1461687089' post='3036774']
Anyone know what Acoustic Control Corporation did to make their solid state amps sound so good compared to other SS models of the day? I think mine runs internally at 70v which suggests limitations similar to the early tranny amps, but it's very loud, with lots of bottom end and not much noise.
[/quote]

You should of just said it has the heft! Lol

[Phil Starr]

[quote name='Chienmortbb' timestamp='1461656453' post='3036413']
Phil the first solid state amps like the Vox T60 were not even using 2N3055 transistors. Of course the real boost in power came with MOSFET. They could be paralleled up to get more current as in the latter HH professional power amps, Trace, Ashdown and Ampeg among others used this technique.
[/quote]

Yes and of course the Mosfets weren't susceptible to thermal secondary breakdown so reliability improved. About that time there was the introduction of integrated circuits as well which made a further huge difference in mass produced amps. I suppose I was answering the OP's question about why early SS amps were so poor. They were under powered due to the cost of high voltage components and unreliable/unstable due to the technology available. We went a long way in the ten years following the early attempts at high powered ss amps.

I guess underneath the OP's question is the thought that we are in the first few years of commercial Class D amps and the problems of these will be sorted as more reliable and better engineered solutions are worked out.

[Chienmortbb]

[quote name='Phil Starr' timestamp='1461690050' post='3036834']
Yes and of course the Mosfets weren't susceptible to thermal secondary breakdown so reliability improved. About that time there was the introduction of integrated circuits as well which made a further huge difference in mass produced amps. I suppose I was answering the OP's question about why early SS amps were so poor. They were under powered due to the cost of high voltage components and unreliable/unstable due to the technology available. We went a long way in the ten years following the early attempts at high powered ss amps.

I guess underneath the OP's question is the thought that we are in the first few years of commercial Class D amps and the problems of these will be sorted as more reliable and better engineered solutions are worked out.
[/quote]Except that I worked on a Sony switching amp (they did not call them Class D then) in the 1970s and there were others around.

I think the reality is that Class D has been victim of outrageous marketing claims. There are many low cost modules that are not very good and even the good ones need to be used correctly. For my 'Work In Progress' home brew amp, I studied most of the commercially available modules and most of them will perform well if properly used.

ICEPower, Pascal, Hypex and Anaview/Abletech as well as some of the Chinese Manufacturers, Connex and BoHoYo make really good modules. Reading the Connex application notes really gives a good insight into the issues associated with Class D.

[gjones]

I owned one of these, from about 1976. It sounded crap, hissed like crazy and was underpowered. It were orrible.

http://youtu.be/1_CbWxi1qAs

[LukeFRC]

[quote name='Beer of the Bass' timestamp='1461663676' post='3036487']
Regarding the earliest amps being made with germanium transistors, I think the Burns Orbit was though I don't know about the others. The inconsistency of germanium transistors must have been a real issue with those - I've played around with them in fuzz boxes and you have to test the gain and leakage of each individual transistor as they're all different!
As a slight aside I was reading about Walter Woods amps yesterday, which would appear to be the first use of class-D and SMPS in musical instrument amps. I find it interesting that those are still revered for their sound today even though the technology was in its infancy at the time.
[/quote] and the price they go for is staggering!

[quote name='Chienmortbb' timestamp='1461691535' post='3036861']
ICEPower, Pascal, Hypex and Anaview/Abletech as well as some of the Chinese Manufacturers, Connex and[b] BoHoYo[/b] make really good modules. Reading the Connex application notes really gives a good insight into the issues associated with Class D.
[/quote] what a great company name!

[luckydog]

Class D is different, because it doesn't rely on device technology, rather it relies on circuit design.

So early examples, if well implemented, might well be good I think. It's yonks old isn't it ?

LD