Opinions on Audiostorm Hotbox attenuator?

chrishill901

I'm looking for an attenuator to tame my DSL50 at gigs - i play with it on 2.5 but it doesnt sound sweet until about 6 or 7 so I'm wanting to get an attenuator to help me raise the volume of the DSL without killing everyone in the room.

I have come across these: http://seanmandrake.com/Products.aspx

I would get the Hotbox 66 so I could have 75% attenuation. Would this be too much?

Mainly im curious about how they are made... I understand from forum dwelling that there are a few ways to make attenuators, some considered better than others... the ebay page hints at how this as made. Does it sound like this will perform for me similarly to a Hotplate? (given that i dont want bedroom volumes)

http://www.ebay.co.uk/itm/AudioStorm-HotBox-60-Power-Brake-Attenuator-Soak-for-valve-tube-amp-/190917522892?pt=UK_Guitar_Accessories&var=&hash=item2c739235cc

thanks for your help

martinw

Simple home made L-pad, using £10-20 of parts.

Functionally will work ok, but tonally poor, and the fixed setting is unlikely to be correct for any given circumstance.

Get a proper attenuator like a Power Brake or Hot Plate.

chrishill901

martinw;69310" said:

Simple home made L-pad, using £10-20 of parts.Functionally will work ok, but tonally poor, and the fixed setting is unlikely to be correct for any given circumstance.Get a proper attenuator like a Power Brake or Hot Plate.

Thank you for your response. I suspected it to be inferior. Do you happen to know if the palmer attenuators are more like the hotplate?

http://www.andertons.co.uk/audio-solutions/pid25468/cid729/palmer-pdi06-power-attenuator-124-8-ohm-version.asp

ICBM

I agree with martinw. It's a very simple, probably purely resistive (the pattern of bolts is distinctive of aluminium-clad wirewound resistors) attenuator, but might actually be pretty transparent, since simple purely resistive ones can be.

I'm guessing that since it takes away 3/4 of the power (75% attenuation) it's a series-parallel arrangement with the real speaker as one of the four loads - essentially a 4x12" with three silent speakers. 75% attenuation is equivalent to -6dB. Whether that's anything like the volume reduction from 6 to 2.5, I'm not sure - I'd guess not as much, but it will probably also make the sound a bit less dynamic and so should reduce the 'killing' effect a bit .

The Hotplate is more sophisticated in that it uses inductors and capacitors as well, but it's not actually as transparent-sounding as many attenuators and can put a bit of extra stress on the valves, especially in Marshalls.

I'd probably look for a second hand Marshall Powerbrake - they're not made any more but aren't too rare, and work very well.

chrishill901

Thanks for your reply what is the killing effect you talk of? I will keep an eye out for Marshall powerbrakes!

ICBM

chrishill901 said:

Thanks for your reply what is the killing effect you talk of? I will keep an eye out for Marshall powerbrakes!

'Killing' as in 'everyone in the room' . Not always caused by the sheer volume, it's often down to the way high frequencies jump out - especially the transients in the note attack - so an attenuator which takes the edge off the tone as well as reducing the volume can be a good thing rather than bad, and you might get more effective volume control than you think from the plain dB figures.

It's noticeable that the difference between a 50W amp and a 100W amp is only 3dB, in actual measurable volume terms - but it often sounds like more than that in reality, because the 100W amp is usually more capable of delivering the high frequency transients.

chrishill901

haha obvious when you put it like that! That is one thing that i'm not a massive fan of; the high frequencies on the DSL red channel can rip your face off... A bit of tone suck in that department wouldnt be totally unwelcome. Shame these attenuators are so expensive!

cosmiccarrot

There's a PB on ebay at the mo, you don't really get these much lower than 100 quid anyway so it's not a bad price and you could make an offer? I'm not affiliated with him btw. Just a heads up.


The PB is the best imo for marshall without going the extreme end of the price range and all attenuators will effect you tone the more you attenuate. The only thing to watch out for with the PB is to turn your guitar down before you start altering the rotary control as it works in notches and as far as I can gather it's an open circuit! between each notch.

http://www.ebay.co.uk/itm/Marshall-Powerbrake-PB100-/261317090294?pt=UK_MusicalInstr_Amplifiers_RL&hash=item3cd7b65bf6

ICBM

cosmiccarrot said:

The only thing to watch out for with the PB is to turn your guitar down before you start altering the rotary control as it works in notches and as far as I can gather it's an open circuit! between each notch.

To be on the safe side, it's not a good idea to switch any attenuator while the amp is producing high power.

breadfan

ICBM said:

cosmiccarrot said:

The only thing to watch out for with the PB is to turn your guitar down before you start altering the rotary control as it works in notches and as far as I can gather it's an open circuit! between each notch.

To be on the safe side, it's not a good idea to switch any attenuator while the amp is producing high power.

Good to know! 

What damage could you do?

cosmiccarrot said:

There's a PB on ebay at the mo, you don't really get these much lower than 100 quid anyway so it's not a bad price and you could make an offer? I'm not affiliated with him btw. Just a heads up.


http://www.ebay.co.uk/itm/Marshall-Powerbrake-PB100-/261317090294?pt=UK_MusicalInstr_Amplifiers_RL&hash=item3cd7b65bf6

I think that's a pretty reasonable price.

I have a Hot Plate. I'd recommend it - it isn't transparent but it's fine at the -4db & -8db settings. I think of it as a necessary evil, although I'd like to compare it to a Powerbrake. @ICBM why does it put more stress on the valves? I'm using a 1987 clone.

ICBM

breadfan said:

I have a Hot Plate. I'd recommend it - it isn't transparent but it's fine at the -4db & -8db settings. I think of it as a necessary evil, although I'd like to compare it to a Powerbrake. @ICBM why does it put more stress on the valves? I'm using a 1987 clone.

It's because the impedance curve is wrong compared to a real speaker - the impedance is too low at high frequencies. It's not too bad at -4 or -8, but at -12 or -16 with the bright switch on it's really much too low - if you run it with the amp cranked and the attenuator set low it visibly stresses the valves if you watch while you play. If you use it like that it's actually better to set the amp to half the impedance of the Hotplate, ie to 8 ohms with a 16-ohm Hotplate. (Cab impedance doesn't matter with the attenuator set low.) It also sounds better.

The Powerbrake is actually the other way round, and the impedance goes slightly too high at high frequencies, but this doesn't seem as much of a problem. It also sounds a bit flat and dull at low settings, but not until you get down to about -18 or -21dB (just left of noon on the dial which is annoyingly not labelled), and is more to do with speaker damping I think.

Purely resistive attenuators have no impedance curve and are thus also too low relative to a real speaker at high frequencies, but they inherently stress the amp less anyway since there is no phase offset between current and voltage (this may be a bit complicated to explain here ), so it isn't an issue.

I don't think it's a good idea to run any amp with the amp really cranked and the attenuator set right down low, anyway - it maximises the stress on everything and usually doesn't sound very good. Much better to use the attenuator to take off the minimum amount you need and set the amp for it like that (including the EQ), not the other way round - I find they actually work better with MV amps and that you shouldn't just turn the MV right up, which is the opposite of what you might expect. That way you can actually make an attenuator sound good even when it's set really low.

breadfan

@ICBM Interesting stuff, as always. 

Would it be possible to use an 8-ohm cab with the 16-ohm Hot Plate & have the amp set for 8-ohms? My main cab is 16-ohm but I also have an 8-ohm cab, which would be useful to use with the same Hot Plate. 

This is a huge advantage the Powerbrake has over the HP, in my opinion - it has a switch for 8-ohm & 16-ohm.

The Hot Plate isn't for what I imagine most people would consider bedroom volume (I think I probably play quite loud at home:) ). You completely lose dynamics at -12 and under & I've never found a use for the bright switch. I don't know about the DSL50, but the 1987 is a brutally loud amp & the Hot Plate does a good job of taming it somewhat.

breadfan

I've just come across this guy on Ebay, he offers a neat HP mod  

"TRUE VOLUME BOOST FOR LIVE PERFORMANCE

The HOT FOOT is a modification performed on your THD Hot Plate that gives it a footswitch-controlled solo boost. With the HOT FOOT, you can turn your Hot Plate up one notch - at any time - using a footswitch!

It works at any attenuation setting. For example, if you have the Hot Plate's attenuation knob set at -8dB, when you hit the footswitch, it goes up to -4dB. Step on the footswitch again and it goes back to -8dB. The knob does not actually move; you get the electronic equivalent of turning the knob."

http://www.ebay.co.uk/itm/Boost-Mod-for-THD-Hot-Plate-16-8-4-2-7-2-ohm-/271302492233?pt=LH_DefaultDomain_0&hash=item3f2ae38049

ICBM

breadfan said:

@ICBM Interesting stuff, as always. 

Would it be possible to use an 8-ohm cab with the 16-ohm Hot Plate & have the amp set for 8-ohms? My main cab is 16-ohm but I also have an 8-ohm cab, which would be useful to use with the same Hot Plate. 

This is a huge advantage the Powerbrake has over the HP, in my opinion - it has a switch for 8-ohm & 16-ohm.

The Hot Plate isn't for what I imagine most people would consider bedroom volume (I think I probably play quite loud at home:) ). You completely lose dynamics at -12 and under & I've never found a use for the bright switch. I don't know about the DSL50, but the 1987 is a brutally loud amp & the Hot Plate does a good job of taming it somewhat.

If the attenuation is set to -8dB or more it doesn't matter at all what the impedance of the cab is - the amp really only sees the Hotplate as the load. (This applies to any attenuator set to about -6dB or lower.)

I found the Hotplate sounds good at -16dB and below with the Deep and Bright switches on. -12dB was the worst-sounding setting. You do have to set the amp up properly for the lowest setting though, don't just set your cranked-up sound and think you'll get the same thing but quieter when you turn down.

It's quite amp-dependent though. It sounded very good with my Mesa, but I liked it a lot less with Marshalls even with the impedance issue taken care of.

chrishill901

Not to hijack this excellent discussion on attenuators but I was curious as to how you think the palmer pdi-06 stacks up against the hot plate? Is it similar in design? The power brake sound superb, trying to track one down!