Attenuator

fnpt

I have been looking into getting the most out of my modest but good sounding Laney cub12 and I am now considering an attenuator. 

The Cub can get a very nice drive sound with the master down to bedroom levels (whisper quiet actually) but that is just pre-amp distortion. It also has a >1w input, fx loop, decent digital reverb, the speaker has been upgraded to a green back, the valves are JJ, so close to the perfect home valve amp.

So the move to an attenuator is mostly that I'm curious to see if the sound will improve if I engage power amp distortion as well in addition to the pre-amp. I am not too worried about loosing any high end with this method considering that the speaker is not being pushed at bedroom levels anyway and the Laney does not warrant a high end attenuator which would be 3x the cost of the amp.

Now, the problem with the Cub is that it is a combo and the internal speaker cable is connected directly from the amp internally into the speaker (not an unpluggable out) which means I have to plug an additional amp-speaker cable from the speaker out jack of the amp into the attenuator and another speaker cable from the attenuator out into the internal speaker.

I'm getting the HB PA-100 attenuator with 4 ohms, 8 ohms and 16 ohms outs, the green back is 8 ohms.

So, my questions are:

- Is it safe to connect an amp-speaker cable directly from the attenuator into the speaker?

- Is it safe to unplug the internal amp-speaker cable and leave it unplugged?

- Will there be any additional safety concerns that I am not aware?

octatonic

fnpt said:

I have been looking into getting the most out of my modest but good sounding Laney cub12 and I am now considering an attenuator. 

The Cub can get a very nice drive sound with the master down to bedroom levels (whisper quiet actually) but that is just pre-amp distortion. It also has a >1w input, fx loop, decent digital reverb, the speaker has been upgraded to a green back, the valves are JJ, so close to the perfect home valve amp.

So the move to an attenuator is mostly that I'm curious to see if the sound will improve if I engage power amp distortion as well in addition to the pre-amp. I am not too worried about loosing any high end with this method considering that the speaker is not being pushed at bedroom levels anyway and the Laney does not warrant a high end attenuator which would be 3x the cost of the amp.

Now, the problem with the Cub is that it is a combo and the internal speaker cable is connected directly from the amp internally into the speaker (not an unpluggable out) which means I have to plug an additional amp-speaker cable from the speaker out jack of the amp into the attenuator and another speaker cable from the attenuator out into the internal speaker.

I'm getting the HB PA-100 attenuator with 4 ohms, 8 ohms and 16 ohms outs, the green back is 8 ohms.

So, my questions are:

- Is it safe to connect an amp-speaker cable directly from the attenuator into the speaker?

- Is it safe to unplug the internal amp-speaker cable and leave it unplugged?

- Will there be any additional safety concerns that I am not aware?

"Is it safe to connect an amp-speaker cable directly from the attenuator into the speaker?"

If you mean Amp -> Attenuator -> Speaker then yes.
You use a speaker cable, not an instrument cable.
If doing the above then you will need two (TS, unshielded) speaker cables.

"Is it safe to unplug the internal amp-speaker cable and leave it unplugged?"

You need to have something (either a speaker or a dummy load) connected to the amplifier speaker output when the amp is running. This product seems to be a dummy load and an attenuator so it will be fine.

"Will there be any additional safety concerns that I am not aware?"

Don't eat the yellow snow.

fnpt

Not much snow around these parts, so not a concern.

To be clear, these are the cables I'm getting:

From amp out speaker jack into attenuator:

From attenuator to speaker:

bertie

fnpt said:

Not much snow around these parts, so not a concern.

To be clear, these are the cables I'm getting:

From amp out speaker jack into attenuator:

 

as long as that is a SPEAKER cable and NOT an instrument/patch cable,  

Ive used 13 amp flex before 

octatonic

fnpt said:

Not much snow around these parts, so not a concern.

To be clear, these are the cables I'm getting:

From amp out speaker jack into attenuator:

From attenuator to speaker:

I can't see if the top cable is unshielded or not.
It needs to be unshielded.

Show me the connections for the top cable.
If it is a regular instrument cable (or what you would use between two pedals) then do not connect a guitar speaker output to it.

fnpt

Thomann says its a speaker cable:

Speaker Cable

• Outstanding quality
• Double-sided mono angled jack 6.3 mm
• 2 x NYS 225L Rean (made by Neutrik) angled jack plugs
• 2 x 1.5 mm², meterware
• Cable diameter: 9 mm
• Length: 0.5 m
• Colour: Black

Thanks @octatonic @bertie ;

Fingers657

I use Ernie Ball Speaker cables .

ICBM

fnpt said:

- Is it safe to connect an amp-speaker cable directly from the attenuator into the speaker?

- Is it safe to unplug the internal amp-speaker cable and leave it unplugged?

- Will there be any additional safety concerns that I am not aware?

You need to use a speaker cable from the amp to the attenuator. You can get away with an instrument lead from the attenuator to the speaker if you don't have a second speaker cable.

Yes, you can unplug the speaker as long as the attenuator is turned right down. Some have a setting specifically marked 'load', but if not just use the lowest setting.

Probably no other concerns, since you already know you need to match the amp and attenuator impedance and not to leave the amp with no load. You will get slightly faster power valve wear if you're regularly cranking the amp right up.

jca74

I run my super cub top  with a marshall powerbreak and can get decent power amp break up through the 1W input without causing the walls to shake, but it's still pretty loud! I use it with the 2x12 cab though since I prefer the sound to the small-cab/combo.

ICBM

For clarity, since it's slightly confusing - the 1W input *doesn't* produce power-amp overdrive - it's not a power scaling arrangement, it engages what's effectively a fixed post-phase-inverter master volume.... so still not the same as turning the conventional preamp master volume down, and it will produce symmetrical clipping (like push-pull power amp distortion), but using the attenuator will still be different, especially if you attenuate from the 15W mode.

jca74

I'll have to start using the 15W input then! It sounded less fizzy with the gain down and volume up to me, which I assumed was the power amp break-up coming in. 

fnpt

Well, I have now tested my Laney cub 12 with the attenuator. Big disappointment. sounds like a blanket has been placed over the amp, even with treble and tone fully dialled in the amp. It looses all highs and becomes dull and muddy.

Once it is in the circuit the HB immediately attenuates the sound by some degree and affects the sound even without attenuating further. It does lower the sound to bedroom levels but at the cost of all dynamics.

My idea was to get an SV20H and use the Green back in my Laney as the speaker via the HB so I'm glad I tested it before investing in the amp.

I do enjoy the pre-amp distortion I get from the Laney at low volumes by using the master so it's not really a problem but unless I get a highly expensive attenuator like the Ox which may not affect the sound as much, any higher wattage amp which requires power amp distortion to sound good or without a master is out of the question.

Dave_Mc

fnpt said:

Well, I have now tested my Laney cub 12 with the attenuator. Big disappointment. sounds like a blanket has been placed over the amp, even with treble and tone fully dialled in the amp. It looses all highs and becomes dull and muddy.

Once it is in the circuit the HB immediately attenuates the sound by some degree and affects the sound even without attenuating further. It does lower the sound to bedroom levels but at the cost of all dynamics.

My idea was to get an SV20H and use the Green back in my Laney as the speaker via the HB so I'm glad I tested it before investing in the amp.

I do enjoy the pre-amp distortion I get from the Laney at low volumes by using the master so it's not really a problem but unless I get a highly expensive attenuator like the Ox which may not affect the sound as much, any higher wattage amp which requires power amp distortion to sound good or without a master is out of the question.

That's been my experience with the HB attenuator too, unfortunately. I guess for £60 it was worth a try, I've wasted more money on stupider things, but I don't really use mine either for the same reason as you. Every so often I get curious again and take it out, try it again for a few minutes and then usually pack it away again for another few months.

I always wonder (the HB being the only one I've tried) if all attenuators suck tone like this (for getting down to bedroom volume) or if I just need to buy a better one... I'd be pretty annoyed if I spent £300+ and it was no better!

fnpt

@Dave_Mc My thoughts exactly. I must now resist the idea of entering the rabid hole of attenuators...

ICBM

No, they don’t all suck tone like that. It’s unfortunate that the HB does, and without looking inside one I don’t know why.

spev11

I've got the same attenuator and I found it to be ok/useable with a bit of a tone tweak. If I set my amp up without it and then put it inline without adjustment then yes it does muddy it up a bit. It works better with my Orange TH30 than It did with my DSL20C. Not sure if that's a factor.
Richtone have a Weber MiniMass in the second hand section if you want to try something thats supposed to be better without going mental.

Ddigger

I have a Marshall Power Brake and a Jet City Jettenuator.  Your HB is a clone of the Jet City one, but I have no idea how alike they really are.

I think it is worth trying another attenuator as I don't think one-size-fits-all.  I try both attenuators in an amp and go with the one that works best.  BTW, there is a Powerbrake in the classifieds right now (last bumped 3 days ago) 
FS: Marshall Powerbrake: 2 available - Amps £ Discussions on theFretBoard

I had to wait a long time to pick up one for less than that asking price.

I looked at the Ox box ones last year.  The second hand prices used to be a bit less than the full price, but I noticed that the second hand prices dropped a lot (but they were still like +£700).  In the reading up I did, I saw that although people loved the sound through headphones and for recording with IRs etc, but many people didn't rate them as an attenuator - not enough step downs and not a good sound.

Maybe someone with some actual experience of an Ox box can chime in here...

fretmeister

relic245

ICBM said:

No, they don’t all suck tone like that. It’s unfortunate that the HB does, and without looking inside one I don’t know why.

I have the hb one and thought it was rather good.

Then again I'm using it to take the edge off rather than tame a beast to be bedroom levels.

NelsonP

I've got a thd hot plate. It has bright and deep switches which remove the blanket over the amp thing pretty well.

bertie

NelsonP said:

I've got a thd hot plate. It has bright and deep switches which remove the blanket over the amp thing pretty well.

ditto, but I wouldnt put the hotplate in the "cheap" bracket

  TBH  all the "cheap -er"  attenuators Ive had  [Weber mini mass and a Dr Z brake lite] have been fine