Power soaks & attenuators

Meole · Post by **Meole** » Wed Aug 11, 2004 11:55 pm

They are always distorting. Turn the gain down and volume up. The tubes even at idle are running at 100%.

Meole · Post by **Meole** » Thu Aug 12, 2004 12:30 am

As you said, it's pretty clean. Pre-amp gain will add distortion, also what type of speakers being used.
You want a speaker (which your amp has) that can handle the volumes you give it without distorting early, so you can hear the amps natural distortion. If you use a speaker that distorts early or is torn or ripped, like they did in the old days, you are getting speaker distortion not amp. Early amps were always clean and hard to distort, so they used to tear and rip speakers. This was only good at low volumes, at high volumes it would sound like mud.

Meole · Post by **Meole** » Thu Aug 12, 2004 12:51 pm

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote> As with all the other products in the AD Range, the AD15/12 features a smooth emission valve rectifier and full Class 'A' circuitry. This means that the amplifier runs at the same voltage regardless of what volume you use it at, so it produces a far smoother and sweeter tone. <hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

This is from Orange: http://www.orange-amps.com/common/guita ... tml#AD1512

Mattk22 · Post by **Mattk22** » Fri Aug 13, 2004 1:21 pm

I tried my AD30 with an attenuator the other day, cranked the volume almost the whole way and it didn't sound that much different then when I had the master at 9 o'clock (gain was always at 11 o'clock). I was really confused about that, but this is the first master volume class A amp I have ever used. Good for me because I didn't need to buy an attenuator. Maybe the review said the sweet spot was with the master around 7 is because he got more air flow through the speakers. I do agree that amps sound better louder because of all the factors that come in to play when playing louder. But, I really don't think the sound of the AD30 changes much with the master volume cranked.

Mattk22 · Post by **Mattk22** » Fri Aug 13, 2004 3:31 pm

Not at 9 at 9 o'clock. without the attenuator the master was about about 3 (or 9 o'clock) and the gain was at about 5 (or 11 o'clock). With the attenuator the master was at 9 or 10 or about 3 o'clock and the gain was the same as above.

irish_admiral · Post by **irish_admiral** » Thu Aug 19, 2004 10:01 pm

Wow, been missing all these fun arguments since I was away on holiday... I do remember Adrian Emsley saying you could send an AD30 'deeper into Class A' by altering the value of the cathode resistors. It seems no-one quite knows what the answer is here, so my solution is eloquent and simple. Do whatever sounds best to you, and means you upset the neighbours ths least (if this is an issue!).

Personally, I prefer to have less gain and more volume.

Joe

Don't tell me the best way, just tell me the cheapest way...

Andy H. · Post by **Andy H.** » Fri Aug 20, 2004 8:24 am

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>Wow, been missing all these fun arguments since I was away on holiday... I do remember Adrian Emsley saying you could send an AD30 'deeper into Class A' by altering the value of the cathode resistors. It seems no-one quite knows what the answer is here, so my solution is eloquent and simple. Do whatever sounds best to you, and means you upset the neighbours ths least (if this is an issue!).<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>Welcome back Irish! I think you at least are dead right!
As far as the 'class A' thing goes, I've been reading around the subject a lot, and trying to sort the garbage from the poo. A couple of thoughts:
Although (in a 'true' class A amp) the output valves are drawing their full current all the time, it doesn't mean that it is always going to the output transformer. At idle - no signal, 100% of it in fact goes up as heat, so your valves get hot hot hot. At full output 50% goes to the OT, the other 50% still goes up as heat. (So in fact the harder you drive the valves the less hot they are because some of the energy goes elsewhere and isn't just dissipated as heat at the plates. Wierd but true!) This explains why class A amps both run hot and are relatively inefficient compared to class A/B ones.
Another thing I've picked up from a couple of different sources, (a bit of a killer crunch this one), which I mentioned earlier on this thread, but no one seemed to pick up on it:
It seems that any pure class A amp running on 4x EL84 valves is limited to about 20 watts or so by the nature and spec of the valves, so your AC and AD30s just aren't running in true class A for their rated outputs. They just aren't, (can't be!), pure class A amps...
Neither will the new Rocker 30 be a pure class A amp, as 2 EL34s running in pure class A will also only give about 20 odd watts. But it puts out 30 watts. I still want one though!
(Hi ho)
So, who D L cares! It's marketing, pure and simple. Ignore it!!! People want to think "Class A = very good quality", anything else is cheap rubbish. I think "Classy amps = very good quality", whether they operate in class A, close to class A some of the time, or in class A/B all the time. There are some very classy amps about, very very few of which actually operate in true class A anywhere near their rated output...
I'm not knocking the amps, just the 'labelling'. But since everyone is doing it, lets face it, it just ain't going to go away! So why worry? Don't! Just enjoy the great sounds without trying to make them what they are not.
Andy.

Edited by - Andy H. on 20 Aug 2004 08:25:04

irish_admiral · Post by **irish_admiral** » Fri Aug 20, 2004 4:37 pm

Which would imply a good reason - no, a necessity, dammit - for cranking the volume high?

Excellent, now I have a good excuse.

Don't tell me the best way, just tell me the cheapest way...

Power soaks & attenuators

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