Hotbox attenuators

lespaulcustom68

Anybody have experience of the AudioStorm (Sean Mandrake)  hotbox 120?

ICBM

Never come across it before, but having just done a bit of searching it looks to be quite good. It seems to be a very simple load-box type attenuator with only two fixed settings, and probably made with just a few high-power wirewound aluminium-clad resistors (the rivet layout is quite distinctive ) and maybe an inductor and other small parts. As such it will probably sound good - it's fairly easy to make that type of attenuator very transparent, it's when you want closely-spaced multiple switchable settings that it becomes difficult.

Given the size of the enclosure and the lack of fan cooling I'd be a bit concerned about running a 120W amp through it though - 120W electrical power maybe, which means no more than a cranked 60W amp really.

ecc83

Listen to ICBM regarding power levels.

Been doing some testing recently and found a 100W nominal amp that can easily put out 160W if you drive its nuts off and that at 230volts mains in.  We often get 240volts and more!

Those allyclad resistors can stand a lot of abuse but the box will get very hot and could hurt someone..

Dave.

lespaulcustom68

Thanks for that. Big thanks to ICBM for the suggested cab idea aswell. Contacted Paula and have the suggested cab thundering away.
Currently using an 8ohm hotplate. Another 16om cab attached in parallel - 8ohm load going to the JMP superbass. I'd like to slim it down to the one cab so after another attenuator for a 16 ohm load cab. I know the THD can take a 16ohm which impacts on the tone controls on the THD, just being careful with a head thats old.

ICBM

Yes, be careful - the THD Hotplate is lower than its correct nominal impedance anyway, and can put a fair amount of stress on the amp, regardless of what THD used to say about them being no worse than cranking the amp through speakers.

It's definitely safe to run the amp at 8 ohms into an 8-ohm Hotplate and then into a 16-ohm cab - at any setting below -4dB the amp only really sees the attenuator as the load, not the cab. It's probably safer still to set the amp to 4 ohms with the 8-ohm Hotplate, if you're really driving the nuts off it.

If you would like more flexibility for connection options I have a 16-ohm Hotplate for sale - I've recently acquired a Sequis Motherload and something has to go! PM me if you're interested.

Glad the cab is doing it for you! It was always a good one, just way bigger than I needed which is why I sold it to Paula in the first place . I've always liked those Blackback 30s, I prefer them to the more 'desirable' Greenbacks - they stay tighter when you push them hard and are more robust.

lespaulcustom68

I believe i've PM'd - but could be wrong??? Slightly different to the old MR site.
:-\"

ICBM

lespaulcustom68 said:

I believe i've PM'd - but could be wrong??? Slightly different to the old MR site.
:-\"

Yes, just got it - I don't get notifications though, for some reason.

Sent you one back .