Power soaks & attenuators

fiveightandten · Post by **fiveightandten** » Sun Aug 08, 2004 12:34 am

That review on HC with the THD and the MASS is a little slanted IMO. He should've done more clips with the MASS.

I have a MASS 100, and it's very transparent, up to a point. Attenuators sound great for reducing stage volume dow to a reasonable level. I can use the MASS to take my OR-120 down to the volume levels a 30W amp would put out, with very minimal coloration. What it doesn't do though, is let me play an amp at bedroom levels and have the tone be unafected.

I think they're all good units...but I choose the MASS for 3 reasons:

-The volume control is continously variable. This was a big thing for me. All the other units have rotary switches for the volume control. What do you do if one click is too loud, and the next one down is too soft? You're out of luck. The MASS volume functions like a volume knob.

-The impedence is selectable. I can switch it from 2, 4, 8, or 16 ohms.

-It's the cheapest unit.

It also uses a real speaker, as opposed to a resistive load. I don't know enough about Attenuators to say what affect this has on tone (other than what i've read)...and I don't think any of us do, except for the designers. But the MASS has treated me great. I can use it as a load box, it's got a very versatile direct out (not like i'll ever use it), the impedence is selectable, and the volume contol is more versatile than any other unit.

I'm sure the Hot Plate sounds just as good, as well as the other units. But that's been my experience with the MASS...

Here's a clip by the way, of my AC-30 with the MASS. The volume was literally at a whisper, as I recorded it my apartment at like 11pm.

Rickenbacker 360
http://www.digitalsoundplanet.com/Membe ... 019325.mp3

I'll record some more clips if you guys would like. I had more but they got deleted off the DSP server cause they were taking up too much space.

Hope that helps.

-Nick

Edited by - fiveightandten on 08 Aug 2004 00:46:03

irish_admiral · Post by **irish_admiral** » Sun Aug 08, 2004 12:56 am

That's cool thanks. Any more Ric 360 mp3 samples would be good. I'm thinking of getting one for my next guitar... that or a G&L ASAT special...

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

spoonie g · Post by **spoonie g** » Mon Aug 09, 2004 2:11 pm

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
That's cool thanks. Any more Ric 360 mp3 samples would be good. I'm thinking of getting one for my next guitar... that or a G&L ASAT special...

Don't tell me the best way, just tell me the cheapest way...
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

ditto.

Matt_plan-R · Post by **Matt_plan-R** » Mon Aug 09, 2004 9:50 pm

My question: isn't one of these used for high powered amps when you want to kinda of dampen (or get power tube distortion) without cranking them volume-wise??

If so, why would you get this with a class A AD30??

Andy H. · Post by **Andy H.** » Mon Aug 09, 2004 9:55 pm

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>My question: isn't one of these used for high powered amps when you want to kinda of dampen (or get power tube distortion) without cranking them volume-wise??

If so, why would you get this with a class A AD30??<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

A/ Yes

Have you never sat in a small room with a cranked 'class A' 30 watter?
They are very loud. That is why!
Andy

Meole · Post by **Meole** » Tue Aug 10, 2004 12:24 am

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
My question: isn't one of these used for high powered amps when you want to kinda of dampen (or get power tube distortion) without cranking them volume-wise??

If so, why would you get this with a class A AD30??

<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

They are usually used for Class"AB" amps where the tone changes with volume increases.
Not sure why it is needed for Class"A" when they sound great at any volume.
I guess if you have one you can use it on a Class"A" amp.

spoonie g · Post by **spoonie g** » Tue Aug 10, 2004 2:06 am

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
My question: isn't one of these used for high powered amps when you want to kinda of dampen (or get power tube distortion) without cranking them volume-wise??

If so, why would you get this with a class A AD30??

<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

They are usually used for Class"AB" amps where the tone changes with volume increases.
Not sure why it is needed for Class"A" when they sound great at any volume.
I guess if you have one you can use it on a Class"A" amp.

<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

for distortion at a useable volume maybe?

Meole · Post by **Meole** » Tue Aug 10, 2004 12:51 pm

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

for distortion at a useable volume maybe?

<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

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

spoonie g · Post by **spoonie g** » Tue Aug 10, 2004 2:10 pm

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

for distortion at a useable volume maybe?

<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

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

<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

oh, I wasnt aware that ac-30's had a master volume.

Andy H. · Post by **Andy H.** » Tue Aug 10, 2004 2:23 pm

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>oh, I wasnt aware that ac-30's had a master volume.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>No, but Orange AD30s do!

Andy.

spoonie g · Post by **spoonie g** » Tue Aug 10, 2004 6:19 pm

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>oh, I wasnt aware that ac-30's had a master volume.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>No, but Orange AD30s do!

Andy.

<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

maybe true, but the amp in question was an ac-30.

Andy H. · Post by **Andy H.** » Tue Aug 10, 2004 9:06 pm

(Slightly pointless this, but)...

Eh?

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>My question: isn't one of these used for high powered amps when you want to kinda of dampen (or get power tube distortion) without cranking them volume-wise??
If so, why would you get this with a class A AD30??
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

!!! <img src=icon_smile_dead.gif border=0 align=middle><img src=icon_smile_sleepy.gif border=0 align=middle><img src=icon_smile_wink.gif border=0 align=middle>

Andy

Edited by - Andy H. on 10 Aug 2004 21:08:49

Andy H. · Post by **Andy H.** » Wed Aug 11, 2004 10:49 pm

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>quote:
Turn the gain up and the volume down...
And when you do that which tubes are distorting????<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>
Oops! Right enough that one slipped by me. (That would be driving those little pre amp valves though, eh?)
I was too busy trying to ignore the other bit: <BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>The tubes even at idle are running at 100%.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>Even if it was (sorry about this, folks) running in true "class A", that 100% bit would be a bit misleading. "The tubes, even at idle, are running 100% of the time, at an average of 50% maximum plate dissipation*" would be rather closer. *(Edit: No, that's rubbish! I'll post later, and try to get it closer to the truth... AH.)
But...
(oh heck, here we go...) Running 4 EL84s in true "class A", you could only get about 20 watts power output.
(Exits slinking stage left, to a chorus of "Shut Up Andy!!!)

Hi Ho!

Andy.<img src=icon_smile_evil.gif border=0 align=middle><img src=icon_smile_blush.gif border=0 align=middle><img src=icon_smile_evil.gif border=0 align=middle>

Edited by - Andy H. on 12 Aug 2004 10:10:15

Meole · Post by **Meole** » Wed Aug 11, 2004 11:18 pm

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote> A class A amplifier is defined as one which is biased to a point where plate current in all the output devices flows for the entire 360 degrees of an input cycle, at the full, unclipped output of the amplifier. This is typically done by biasing the output stage halfway between cutoff and saturation, with the plate load impedance to an appropriate value that gives maximum undistorted output power. This is the least efficient method of amplification, because the output devices are dissipating maximum power with no input signal. 
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote> Now, what are the differences, you might ask? Well, for one, the Class AB amplifier is biased in a more non-linear portion of the characteristic curves, which means it has more distortion than a true class A amplifier. Also, the efficiency will be greater than is theoretically possible with a class A amplifier at these levels. There is a very real difference in tone and operating conditions between a true class A 10W amplifier running at say, 1W, and a 10W class AB amplifier running at 1W. Same output level, same overall power level, *but* a different class of operation, different amount of distortion, different efficiency, *and* a different tone, even though neither one of them is in cutoff for any portion of the output cycle at that low level. This is due to the bias point differences and load line differences. The differences become even more apparent when the amplifiers are run at their full undistorted output power. The true class A amplifier will have no crossover distortion, while the class AB amplifier will. The average plate current for the true class A amplifier will not change, or will change very little, from idle to full output power, while the average plate current in a class AB amplifier will increase dramatically. This will lead to "sag" in the power supply that doesn't exist in the true class A amplifier, which again results in a tonal change. <hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Info on Class "A" and "AB" I got this quote from: http://www.aikenamps.com/ClassA.htm

Meole · Post by **Meole** » Wed Aug 11, 2004 11:38 pm

Pre-amp tubes. The power tubes are disipatting the same power at any volume level.
When the volume is turned up the speakers may start to distort but the amp is still disipatting the same power.

Power soaks & attenuators

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