Artisan 15 (attenuation)

ICBM

ecc83 said:

I reckon swapping the two blue wires over will sort the pot direction out.

I think you need to swap the blue and brown at the top right in the pic. It looks to me like terminal 2 (rotor/output) is the lower left - you need to swap 1 and 3.

ecc83

ICBM said:

ecc83 said:

I reckon swapping the two blue wires over will sort the pot direction out.

I think you need to swap the blue and brown at the top right in the pic. It looks to me like terminal 2 (rotor/output) is the lower left - you need to swap 1 and 3.

Could be squire, could be but so long as he only tries one set at a time he can do little harm.

Dave.

Dave_Mc

ICBM said:

Without an FX loop, an attenuator is the only practical option. As Dave said, a ‘100W’ L-Pad* would be adequate for an amp of this power rating, and is the cheapest - and actually a pretty good-sounding - option. You don’t even really need an enclosure, you could just mount it on a bracket screwed to the inside of the cabinet round the back - they’re air-cooled rather than using a heatsink.

The Harley Benton one isn’t bad either, if you would prefer a bought-in solution.

(*The reason they’re called 100W is historic, but they’re only really suitable for up to about a 20-25W guitar amp.)

Just out of interest, would the L-Pad sound better than the Harley Benton? I know usually someone on Ebay is selling them, though whether they're made competently I guess is the thing...

ICBM

Dave_Mc said:

Just out of interest, would the L-Pad sound better than the Harley Benton? I know usually someone on Ebay is selling them, though whether they're made competently I guess is the thing...

Hard to say - the L-Pad is usually pretty transparent. I haven't tried the HB.

DCS222

Just for my information, as I can see 2 Jack sockets… the amp plugs into this and then into the speaker… is it uni directional? Does it matter which socket plugs into which? 

And will it alter the ohm rating? 

relic245

DCS222 said:

Just for my information, as I can see 2 Jack sockets… the amp plugs into this and then into the speaker… is it uni directional? Does it matter which socket plugs into which? 

And will it alter the ohm rating? 

Yes it does matter which plugs into which. 

I'm 99.09% sure that the one on the front comes from the amp and the one on the back goes to the speaker. 

The 0.01 percent of me would be slightly cautious in firing it up. 

What I'd do is:
Plug a cable from the amp into the front
Plug a cable from the back into the speaker
Set the amp to be a reasonable room volume ie not blow your head off
Set the control on the attenuator half way
Turn amp onto standby and let it warm up
Turn the amp on fully and if you don't have a sound turn it off again....

As I say my memory tells me that is correct and to my logical brain it would also make sense to have the input on the front.

Looking at the photos of the wiring the jack on the left (which will be the back) has 2 wires, one goes to ground and the other to the pot. From my limited electronics theory that would also indicate that it's the out. Perhaps @ecc83 can give us the definitive answer. 

As for ohm rating. This was designed for an Artisan 30 head into an artisan 2x12 cab I'm pretty sure that the default was 8 ohms so that is what it will have been speced for. I'd assume that the A15 is the same? 

ICBM

relic245 said:

I'm 99.09% sure that the one on the front comes from the amp and the one on the back goes to the speaker. 

Yes - front from amp, back to speaker.

DCS222

The manual suggests it’s a 16 ohm speaker, you can have 16 or 8ohm settings on the amp

ecc83

ICBM said:

Dave_Mc said:

Just out of interest, would the L-Pad sound better than the Harley Benton? I know usually someone on Ebay is selling them, though whether they're made competently I guess is the thing...

Hard to say - the L-Pad is usually pretty transparent. I haven't tried the HB.

Unless the HB has any 'reactive' elements in it they are likely to sound pretty much the same...just resistors.

There will be a minor difference in the ABSOLUTE value of the loading but I doubt it will be audible. 'S'only Rock n Roll!

Dave

relic245

DCS222 said:

The manual suggests it’s a 16 ohm speaker, you can have 16 or 8ohm settings on the amp

Ok then it may be good if Dave can let us know if that is going to make any difference as I'm sure that it was speced to work with 8 ohms. Whether that matters, I don't know.

ecc83

relic245 said:

DCS222 said:

The manual suggests it’s a 16 ohm speaker, you can have 16 or 8ohm settings on the amp

Ok then it may be good if Dave can let us know if that is going to make any difference as I'm sure that it was speced to work with 8 ohms. Whether that matters, I don't know.

Well, putting a resistive 8R load on an amp set for 16R* is a bit naughty but should not cause it much grief so long as it is not being thrashed to death for a long time when it might pop an HT fuse. Problem is, since you are using a power soak you ARE going to be giving the amp the beans a lot of the time!

That said, me learned friend ICBM has often stated that amps sound better when the R load is a bit higher than nominal? So, 8R tap on amp, 10R'ish load R. But, all the Artisan range are very tough and I doubt you could damage one whatever the load other than prolonged high drive into NO load.

*The other way, 8R tap 16R load is much better avoided. Spiky, spiky voltages!

Dave.

ICBM

DCS222 said:

The manual suggests it’s a 16 ohm speaker, you can have 16 or 8ohm settings on the amp

Whichever it is, set the amp to match the attenuator and not the speaker, since the amp now sees the attenuator as its load.

ecc83 said:

That said, me learned friend ICBM has often stated that amps sound better when the R load is a bit higher than nominal? So, 8R tap on amp, 10R'ish load R.

The average impedance of a real speaker is a bit higher than the nominal rating, due to the fairly steep rise at higher frequencies - it will go up to something like 20 ohms at the top of the audio range, for an 8-ohm speaker. A 10-ohm resistive load is still well within this, so perfectly OK. It may also be why they can sound better.

DCS222

Should be able to measure it with a multimeter, can’t I?  Because when I read the 2x12 cab manual, it can be run 16 or 8 ohm.

“Impedance: Stereo - 2 x 16 Ohms. Mono - 8 Ohms. Selectable by input jack”

ICBM

DCS222 said:

Should be able to measure it with a multimeter, can’t I?  Because when I read the 2x12 cab manual, it can be run 16 or 8 ohm.

The DC resistance can be measured with a multimeter, but isn't the same as the impedance. The DC reading will usually be about 2/3 to 3/4 of the nominal impedance.

You can only run it at 8 ohms if you're only using one speaker.

DCS222

Sorry, I should have been clearer… the 2x12 cab was what relic245 used with his artisan 30 head… the 15 combo I have is definitely a 16ohm speaker. So if I put the load box between my amp and my speaker, I must flick the switch to 8 ohm.

 Thanks for all the help everyone… sorry to be a bit fick!

Dave_Mc

ICBM said:

Dave_Mc said:

Just out of interest, would the L-Pad sound better than the Harley Benton? I know usually someone on Ebay is selling them, though whether they're made competently I guess is the thing...

Hard to say - the L-Pad is usually pretty transparent. I haven't tried the HB.

Thanks The HB definitely isn't, though I get the feeling that most attenuators cut a lot of treble with extreme attenuation.

ecc83 said:

ICBM said:

Dave_Mc said:

Just out of interest, would the L-Pad sound better than the Harley Benton? I know usually someone on Ebay is selling them, though whether they're made competently I guess is the thing...

Hard to say - the L-Pad is usually pretty transparent. I haven't tried the HB.

Unless the HB has any 'reactive' elements in it they are likely to sound pretty much the same...just resistors.

There will be a minor difference in the ABSOLUTE value of the loading but I doubt it will be audible. 'S'only Rock n Roll!

Dave

Thanks I think the standard HB one I have is just resistive, but I could be wrong.