Members EdgeOfDarkness Posted May 20, 2012 Members Share Posted May 20, 2012 You guys tried the lunch box? Buddy brought one over to jam tonight. It's pretty loud and very small. On its own it's not high gain, can Do mid gain stuff but he runs a GT8 into It. Pretty cool little combo. 200 watt. " the loudest little amps in the world" http://www.ztamplifiers.com/products/lunchbox.html T Link to comment Share on other sites More sharing options...
Members isvoid Posted May 20, 2012 Members Share Posted May 20, 2012 Watched lots of yt vids of this over 6 months ago. Interesting but can't say I was moved to buy one. Link to comment Share on other sites More sharing options...
Members EdgeOfDarkness Posted May 20, 2012 Author Members Share Posted May 20, 2012 It's nice for the size , easily loud enough in a full band situation.If I had the 4x12's there I would have hooked them up. Link to comment Share on other sites More sharing options...
Members teemuk Posted May 20, 2012 Members Share Posted May 20, 2012 It's more like 60 watts on average and readings closer to 200W can only be juiced out during momentary peaks. Even that is doubtful considering the fact that the amp is rated to draw 200W from the socket and a 100% efficient amplification is sort of an impossiblity - especially in a class AB amp. Also, completely underrated design (tiny power transformer, inadequate heatsinking and chassis ventilation) for a 60W class AB amp so the several reports of the amp overheating aren't exactly very surprising. Link to comment Share on other sites More sharing options...
Members newholland Posted May 20, 2012 Members Share Posted May 20, 2012 It's more like 60 watts on average and readings closer to 200W can only be juiced out during momentary peaks. Even that is doubtful considering the fact that the amp is rated to draw 200W from the socket and a 100% efficient amplification is sort of an impossiblity - especially in a class AB amp. Also, completely underrated design (tiny power transformer, inadequate heatsinking and chassis ventilation) for a 60W class AB amp so the several reports of the amp overheating aren't exactly very surprising. i'm sure it's all compromises. you'd kinda have to be a little wrongheaded to think a lil 6.5" speaker and a teeny little box'd roar all night without over heating.. that' be like rolling into a rock show with a polytone. great amps-- but not for wembley-esque roar.. 200 watts is kinda hysterical unless it's some sort of chip amp... good grief! i've been curious though-- haven't got much use for anything like that-- but it's a nifty concept.. pocket amp! Link to comment Share on other sites More sharing options...
Members Warhorse Posted May 20, 2012 Members Share Posted May 20, 2012 does it run on dc? Link to comment Share on other sites More sharing options...
Members teemuk Posted May 20, 2012 Members Share Posted May 20, 2012 200 watts is kinda hysterical unless it's some sort of chip amp... good grief! It IS a chip amp, a generic class-AB chip amp, no switching class-D in it. Expect maybe a 60% efficiency. Some forum quotes about the power... I contacted Ken Kantor [the guy who designed the amp] and asked him how they got the 200 Watt number and he answered: The 200W number is based on peak voltage. Other numbers we list, for more sustained signals, are based on a THD of under 10%. Just FYI, the >minimum 200 Watts is the equivalent RMS power available for 100mS tone bursts from 250Hz to 2500Hz. The actual driver impedance is used in the calculation. I also asked about continuous power and got this answer The answer is that it depends:there are sophisticated thermal limiting/SOA mechanisms built into the amp, that make testing it the way you suggest [using a 1kHz sine wave into a dummy load]not very straight forward. The longer the signal is applied, the lower the apparent "RMS" power will be. If you measure it within 0.5 seconds, you will see an unclipped RMS power approaching 130W. At the other end of things, the RMS will tend downward towards about 60W, steady-state. Read: Burst power rating is maybe 200 watts at best, dropping quickly to 120 watts. These ratings are for a highly distorted transient signal. Average continuous power at low distortion is about 60 watts. The only useful measure is, of course, the 60W average rating. A second quote from Ken Kantor: Unlike some other portables, especially ones that run off wall warts or batts, the Lunchbox really does hit high power levels. I completely understand that this data won't make any difference if you don't like the sound of the amp, or think its a good value, but here it is: Typical RMS Power: 125W. Typical Music Power: 200W. (based on 100mS tone bursts) Typical Peak Power: 315W. (instantaneous peak output) ...so which one is it? Both answers coming from the same guy. Seems that the power rating just mysteriously gets higher and higher. This time it's more than what the amp even draws from the socket. Yet a third one from Kantor: Maximum Instantaneous Peak Power: 280W Musical Peak Power: 236W RMS Power: 130W Sustained Average Music Power: 200W He obviously forgot the "Unobtainable super power multiplied by shoe size" = 1.21 Jigawatts Here's some statistics of performance of Lunhboxes of a certain TGP forumite: First Lunchbox ( # 324 ) arrived on 8-6-2009. Died on 8-30-2009. Second Lunchbox ( # 1517 ) arrived on 9-6-2009. Died on 10-11-2009. Third Lunchbox ( # 3738 ) arrived on 10-16-2009 And... I'm going to have to butt in and agree with you. I've had my PowerBlock going on 4 years without a problem. I bought one of these things thinking it might be handier for rehearsals. It worked great until the third time I used it. I just went dead and never turned on again. I owned it for literally two months! - Power transformer is about half the size you'd commonly find from a 60W amp. - The rear plate is the heatsink. Usually good 60W amps have big finned heatsinks for efficient heat dissipation. In Lunchbox the rear plate can get too hot to touch, which essentially means the semiconductors are on the verge of dying. - No chassis ventilation. All that heat from the output chip and the power transformer just packs up inside. - ZT "fixed" this by introducing an even less efficient power transformer, which on high power demand sags so much it limits the output power and hopefully the waste heat. Hopefully. Give me a Crate Powerblock any time instead of this amp, thank you. Link to comment Share on other sites More sharing options...
Members kkantor Posted May 21, 2012 Members Share Posted May 21, 2012 Tough crowd tonight! Actually, the power rating didn't mysteriously get higher, it mysteriously got lower. This was part of solving the overheating problem. The issue is fixed, along with the noise problems that plagued early production. Incidentally, I don't agree with you that average power is the "only important" power spec. Music has a high crest factor, and an amp must have the headroom to handle transients. Further, "sag" and other types of supply modulation are an intentional aspect in the design of a good guitar amp. Lastly, the newer transformer has higher efficiency, not lower efficiency, obtained via a reduction in DCR. Hey, I appreciate the feedback, even the not-so-good feedback. We got beat up about the problems with the early LB's, and that led to many improvements. The last 10,000ish units in the field are quite solid. Service and return rates are running under 0.5%, several times better than industry averages. - ken.kantor@ztamplifiers.com PS- We just found out that Sonic Youth will be touring with Clubs soon! I'm psyched! It IS a chip amp, a generic class-AB chip amp, no switching class-D in it. Expect maybe a 60% efficiency. Some forum quotes about the power... Read: Burst power rating is maybe 200 watts at best, dropping quickly to 120 watts. These ratings are for a highly distorted transient signal. Average continuous power at low distortion is about 60 watts. The only useful measure is, of course, the 60W average rating. A second quote from Ken Kantor: ...so which one is it? Both answers coming from the same guy. Seems that the power rating just mysteriously gets higher and higher. This time it's more than what the amp even draws from the socket. Yet a third one from Kantor: He obviously forgot the "Unobtainable super power multiplied by shoe size" = 1.21 Jigawatts Here's some statistics of performance of Lunhboxes of a certain TGP forumite: And... - Power transformer is about half the size you'd commonly find from a 60W amp. - The rear plate is the heatsink. Usually good 60W amps have big finned heatsinks for efficient heat dissipation. In Lunchbox the rear plate can get too hot to touch, which essentially means the semiconductors are on the verge of dying. - No chassis ventilation. All that heat from the output chip and the power transformer just packs up inside. - ZT "fixed" this by introducing an even less efficient power transformer, which on high power demand sags so much it limits the output power and hopefully the waste heat. Hopefully. Give me a Crate Powerblock any time instead of this amp, thank you. Link to comment Share on other sites More sharing options...
Members isvoid Posted May 21, 2012 Members Share Posted May 21, 2012 The last 10,000ish units in the field are quite solid. To be candid ... as much as I might conceptually dig the amp comments like that tend to completely defuse any GAS. Link to comment Share on other sites More sharing options...
Members A_Gitarman Posted May 21, 2012 Members Share Posted May 21, 2012 Well, I've been using a LB as a backup/ practice amp for about 1.5 years now & it has worked flawlessly. While it (obviously) lacks bottom end, it takes pedals well and I can hear myself over the drummer without having to 'dime' it. Along with using it at rehearsals, I've run it as both a personal monitor and in stereo with my regular rig at a couple of gigs and it worked GREAT in both cases. Furthermore, I found that the LB extension speaker helps fill it out a little, but it sounds MUCH better through a decent cab. I throw it under the back seat of my Jeep before every gig, just in case my main amp gives out for any reason. In fact, it came in quite handy when one of my band-mate's amps fried just before a gig. We threw it on top of his amp, dropped a mic in front of it, & he was good to go My only gripes with it are that 1) the trim around the back is starting to peel off, 2) the finish scuffs easily, & 3) the 'gain' sounds are pretty sucky. Link to comment Share on other sites More sharing options...
Members kkantor Posted May 23, 2012 Members Share Posted May 23, 2012 To be candid ... as much as I might conceptually dig the amp comments like that tend to completely defuse any GAS. Thank you for sharing. -Ken Kantor ken.kantor@ztamplifiers.com Link to comment Share on other sites More sharing options...
Members kkantor Posted May 23, 2012 Members Share Posted May 23, 2012 Thanks much!! If you get a chance, try out the new Junior. It has an overdrive that is more like what guitarists expect. (New cabinet shop, too....) The problem with the Lunchbox is that we originally tried to make it a more general purpose amp, potentially usable for a range instruments. So the gain pot is really a front-end sensitivity trim, not a distortion control. That was a mistake, as the amp is almost 100% used as a guitar amp, and nobody finds the control useful. Or the Ambience, which has its own sad story. Ah well, live and learn. - Ken Kantor ken.kantor@ztamplifiers.com Well, I've been using a LB as a backup/ practice amp for about 1.5 years now & it has worked flawlessly. While it (obviously) lacks bottom end, it takes pedals well and I can hear myself over the drummer without having to 'dime' it. Along with using it at rehearsals, I've run it as both a personal monitor and in stereo with my regular rig at a couple of gigs and it worked GREAT in both cases. Furthermore, I found that the LB extension speaker helps fill it out a little, but it sounds MUCH better through a decent cab. I throw it under the back seat of my Jeep before every gig, just in case my main amp gives out for any reason. In fact, it came in quite handy when one of my band-mate's amps fried just before a gig. We threw it on top of his amp, dropped a mic in front of it, & he was good to go My only gripes with it are that 1) the trim around the back is starting to peel off, 2) the finish scuffs easily, & 3) the 'gain' sounds are pretty sucky. Link to comment Share on other sites More sharing options...
Members kkantor Posted May 23, 2012 Members Share Posted May 23, 2012 does it run on dc? No, but the new Junior does. - Ken Kantor ken.kantor@ztamplifiers.com Link to comment Share on other sites More sharing options...
Members EdgeOfDarkness Posted May 23, 2012 Author Members Share Posted May 23, 2012 I actually liked the ambience control. Link to comment Share on other sites More sharing options...
Members StankNasty Posted May 23, 2012 Members Share Posted May 23, 2012 Sonic Youth uses them? No thanks. Link to comment Share on other sites More sharing options...
Members EdgeOfDarkness Posted May 23, 2012 Author Members Share Posted May 23, 2012 What is the estimated price on the .jr? It's half the size of the lunchbox? Link to comment Share on other sites More sharing options...
Members peavey_impact Posted May 23, 2012 Members Share Posted May 23, 2012 150 watts Link to comment Share on other sites More sharing options...
Members isvoid Posted May 23, 2012 Members Share Posted May 23, 2012 Thank you for sharing.-Ken Kantorken.kantor@ztamplifiers.com Thank you for listening objectively. -Izzy isvoid@gmail.com Link to comment Share on other sites More sharing options...
Members A_Gitarman Posted May 23, 2012 Members Share Posted May 23, 2012 Thanks much!! If you get a chance, try out the new Junior. It has an overdrive that is more like what guitarists expect. (New cabinet shop, too....) The problem with the Lunchbox is that we originally tried to make it a more general purpose amp, potentially usable for a range instruments. So the gain pot is really a front-end sensitivity trim, not a distortion control. That was a mistake, as the amp is almost 100% used as a guitar amp, and nobody finds the control useful. Or the Ambience, which has its own sad story. Ah well, live and learn. - Ken Kantor ken.kantor@ztamplifiers.com no worries, Ken. I run my old DigiTech RP1 in front of it for distortion, EQ, & efx... works great. The Ambience knob is interesting, but I concur that I don't really get any use out of it. I could see maybe using it to add a little color to a mic-ed wind instrument or something, though Link to comment Share on other sites More sharing options...
Members Moe Humble Posted March 11, 2013 Members Share Posted March 11, 2013 Ok. I travel a LOT, and spend lots of nights in hotels. I need a small amp to take with me for playing jazz guitar. I am not looking for built in distortion or gain goodies. I don't use pedals, just want to hear my guitar and perhaps take it out to sit in..... That's about it. The Micro Roland with the one speaker, just doesn't make it.I'd like to fit this in a suitcase, and not blow my weight Limit. I was thinking about the LB, but maybe the LB Jr. might work. I have heard the LB on stage and it was pretty hip.All the chit chat about RMS / and delta between 200 and 60 watts is nice, but I don't really care. I do like the 1% THD. I just need portable, tone, light and easy.Any Comments? Ken? Link to comment Share on other sites More sharing options...
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