#1
OK, I recently bought a Laney LC30 Mk II Tube combo and it definitely has a nice sound, but as is generally the case with tube amps, you need to crank the volume up to get the most out of it, which isn't very practical for the place I'm living in at the moment, anyway I was reading some reviews of the amp on Harmony Central and one guy who had one said:

Altought the sound remain resonably good at low levels i suggest to build a very simple DIY project for reduce, with a switch, volume and have a extrabonus of line out for drive a PA mixer. This project is called speakerbox.pdf (8 ohm volume reducer an line out box) and you can find it on Blue Guitar site. It work very good an allow you to use more volume in the amp for have a more Big and compressed sound without ears crushing! This amp can be too loud for some situations ( little venues, beedroom, pratice with group)

So I had a look on Blue guitar site but couldn't find anything called 'Speakerbox' though I did find the following schematic, which appears to do the same thing as he's describing:

http://www.blueguitar.org/new/schem/misc_mod/volreduc.gif

It doesn't look as if it would be very hard to build, but what I'm wondering is: has anyone here tried using a circuit like this? does it work? and is it safe? will it harm my amp? Any thoughts?

Edit: also where the F do I buy 50 W resistors?
Last edited by Mr Songwriter at Aug 16, 2006,
#3
^^that'll work until the resistor explodes or catches on fire and damages the amp.
Ibanez -> Peavey -> Eardrums

Apparently I'm on some list of people to listen to..?
#5
a) have you done this yourself?
b) what value would the pot be?
C) wouldn't I need to shield that circuit?
#6
Quote by Funky P
^^that'll work until the resistor explodes or catches on fire and damages the amp.


Which one? the vol_reduc circuit or old toad's suggestion?
#7
THD Hotplates are great for this kinda thing! I think the volume box type things have to go in the FX loop and only "control" preamp distortion, not power amp which most people prefer to a broken up preamp.
#8
ok heres the thing its going to act like an additional 8ohm speaker load so you impeadences wont match between the speaker and the amp which can lead to breaking your amps transformers that cant cope with that much impeadence, but if your set on doing it you need to look for power resistors but you can allways make a speaker isolation box to put your amp in and then just mic it.
#9
Quote by tomslespaul
THD Hotplates are great for this kinda thing! I think the volume box type things have to go in the FX loop and only "control" preamp distortion, not power amp which most people prefer to a broken up preamp.


I'm aware of the hotplates, the problem being they start at about £200, and as far as I can tell this circuit is a cheapo version of one of them (hence the power resistors and the picture of the speaker in the schematic)

ok heres the thing its going to act like an additional 8ohm speaker load so you impeadences wont match between the speaker and the amp which can lead to breaking your amps transformers that cant cope with that much impeadence, but if your set on doing it you need to look for power resistors but you can allways make a speaker isolation box to put your amp in and then just mic it.


Thanks for the info, that was what I was worried about, so I don't think I'll risk it, I don't really have room in my flat for a speaker isolation box, cool as that would be.
#11
Quote by sempri_fi
^who does have room for a speaker isolation box???


Lucky so-and-so's whose places aren't all cluttered up with amps, guitars etc.
#12
exactly so the only real option is the power attinuator or just turn it up and let the neghbors complain...
#13
Naah, I'll get evicted if I do that, guess I'll just have to put up with the less-than-perfect tone until I get a rehearsal room or something.
#15
http://amps.zugster.net/articles/attenuation

check that out
there's alot of info on Attenutators and how to build your own. Try the T Bridge one, it's better than the L Pad.

And as for the Blue guitar, they have a better method of reducing volume on their, they call it a Power Soak Box. It's on the same FTP server, just need to know what you're looking for.
I atached the schematic for you.

If you're willing to spend a little more cash, get one of the Weber attenuators. Much cheaper than a Hot PLate, and it sounds alot better. Doesn't use resistors, it uses a real speaker motor, so it sounds more natural. Only 100 bucks, in US, for their 50 watt model.
http://www.tedweber.com/atten.htm
Last edited by forsaknazrael at Aug 16, 2006,
#16
I have the Weber Minimass, it's quite nice.
Weber sells a kit for one too, IIRC.
Looks like that link above should answer your questions...
And old_toad you get a warning.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#17
Yeah, I've been meaning to buy myself one. What I've heard is fantastic.
I tell ya, 5 watt tubes are still too loud for an apartment
#18
Thanks for the info and links, Metallicaman and forknazrael, I would definitely like to check one of those Weber attenuators out but there aren't AFAIK any guitar shops in my area that sell them, though there is one that stocks the THD hotplates, so I might take my amp in to check them out, there is also a 2W tube amp called the Matamp Minimat which has a built in attenuator, they're about the same price as the attenuators (£250) so I could run it through a spare 2 x 12" cab I've got, or even the speaker in my Laney.

There's a review here of the 25W version of the Minimass with soundclips:

http://www.grailtone.com/guitar-reviews/weber-eminimass-review.html
Last edited by Mr Songwriter at Aug 17, 2006,
#19
Quote by That_Pink_Queen
I have the Weber Minimass, it's quite nice.
Weber sells a kit for one too, IIRC.
Looks like that link above should answer your questions...
And old_toad you get a warning.


I had a MiniMass and I thought it was terrible, it took off so much treble, made the sound all mushy. I actually eventually sold it on ebay for more than I bought it for Seems like the new Economy one has a treble compensation switch though which could make up for the tone loss..

I got lucky and found a hotplate 2nd hand for around £130 I think, its so much better than the MiniMass!
Last edited by tomslespaul at Aug 17, 2006,
#23
because it runs it on a different voltage than what it was designed to run on so it can shorten tube life and damage your transformers. remember V=IR so if voltage changes so does the amp draw and/or the resistance also changes.
#24
Can you make the same type of thing for a ss amp? I have a 40 watt solid state amp and cant really crank it, but when I turn it down the distortion sucks, even with a pedal. So can it be done?
#25
with a ss amp it wouldnt change anything, it would just be quieter. ss amps dont work the same way as a tube amp does, the louder you push a ss amp the louder it gets untill it clips and sounds horrible, but with a decent amp everything between clipping and 0 sounds prettymuch the same, if you need better distortion get a tube booster pedal from www.olcircuits.com or a tube screamer (ts-9 or ts-808).