ISP Stealth Ultra-Lite power amp (90 watts RMS into 4ohms at 0.9lb)

guitarfishbay

Haven't seen a price yet, but in terms of size/weight I think this is pretty interesting.  In my own experience an EHX 44 Magnum is actually loud enough to keep up with a band (just is comparatively thin on the low end at higher volumes) so this having double the power could be a great product.

Danny1969

Mmm see'ing as how it's gonna need a 19V PSU of at least 5.5 amps or so the power supply is probably bigger than the amp

guitarfishbay

Wouldn't that be similar to the PSU you need for the EHX 44 Magnum?  It's not really much of a deal if so.

olafgarten

guitarfishbay said:

Wouldn't that be similar to the PSU you need for the EHX 44 Magnum?  It's not really much of a deal if so.

I think the 44 Magnum is 3A @ 24v so thats 72W whereas this is 5.5A @ 19v making 104.5W, it would be slightly bigger but not huge. It would be the same as a Largeish Laptop Charger.

ecc83

Oh! I WISH I had taken pictures at the time! Years ago I built a 100V line amp for our rifle range.

The actual amps were ICs (like 2030s) the design culled from a mag and called "The Matchbox Amplifier" and indeed it would have fitted in a box of Swan! The silly part was the OP traff which was a 250W unit from a scrap amp that had 8 2N 3055 (type but higher rated) OP transistors. The amp was powered from a 12 car battery and the other absurdity was the decoupling cap. 22,000 mfd at 35V bigger than a bake bean tin!

The speakers were explosion proof horns salvaged from a defunct tannery and it all worked very well!

Dave.

Danny1969

Do you drive a modified DeLorean Dave ?

NPP

all this looks like a game changer (just take a small modeller and a small power amp) until you realise that you still need a speaker to produce any sound - at which point you might just as well bring a combo amp. 

For a backup it is probably too expensive ...

John_A

I tried an ISP stealth a while ago, my magnum 44 was louder and sounded better, a lot better

guitarfishbay

John_A said:

I tried an ISP stealth a while ago, my magnum 44 was louder and sounded better, a lot better

That's interesting.  Is that at full volume?  The stealth is supposed to be 180 watts mono which should be a fair amount more power.

I found the Magnum was very shouty - so it could get quite loud, but it really had very little low end.

John_A

My band mustn't be as loud as yours, I found the magnum to be more than loud enough to gig with using a AMT preamp, the ISP just wasn't as loud before it started to break up, the Magnum also sounded a lot better, the ISP sounded very sterile.

only had it on loan for one gig though, I may have missed somthing.

guitarfishbay

Just discovered this from Seymour Duncan, 170 watts and has 3 band EQ.

http://www.seymourduncan.com/power-amp/powerstage-170

digitalscream

@guitarfishbay - that SD looks much better. 170W into 4R is probably about 100W into 8R, which is going to be a lot cleaner at gig volume. Also, it looks like it doesn't have an external power supply, which is bloody marvellous.

guitarfishbay

Yeah it does look more useful. Looks like they're also doing a higher power one, not pedalboard sized but still pretty compact

http://www.seymourduncan.com/power-amp/powerstage-700

ICBM

digitalscream said:

@guitarfishbay - that SD looks much better. 170W into 4R is probably about 100W into 8R, which is going to be a lot cleaner at gig volume. Also, it looks like it doesn't have an external power supply, which is bloody marvellous.

SMPS amps often fall off linearly, since there is almost no power supply sag - so 170W into 4R becomes 85W into 8. Not that it makes a lot of difference really…

The interesting thing is that the *worse* the power supply - in technical terms - the *better* the power output holds up at higher impedances.