Cheap amps

[Ike]

I'm looking at a quick replacement for a number of power amps that were recently stolen from a club in manchester. They will be fixed, there inputs will be limited and they will not be driven too hard, however we can afford to pay hardly anything for them.

 

What I would like to know is why are cheap amps (such as the t.amps from thomann) so cheap. Is it just poor physical construction and maybe a case of using someone elses R+D or are there problems with the electrical design, skimping on power supply components etc?

 

Has anyone heard the t.amps in anything like a test condition or got any figures for them, anyone know if they are a copy of something and if so what?

 

Please dont simply reply with "you get what you pay for", what I want to know is what im not getting fom the thomann ones. As I said before I cant afford professional brands...even second hand.

 

Sorry about all the questions...I have googled, honest!

 

 

Thanks,

 

Ike

[Matt Riley]

I think that the question that you need to ask is what makes a good power amp. I'd say - in no particular order - slew rate, power, damping factor, THD, noise floor, thermal stability, light weight, reliability, and after sales service. Chances are that the cheaper amps are going to sacrifice good specs in a number of these areas to enable them to make them cheap.

 

Regards,

 

Matt

[dan slv-tech]

Just my 2p worth,

 

the far east are crap at building power supplies (behringer desk anyone), ive tried a few far eastern power amps, some are really good, some are awful, like before, weight, quality of components, construction, servicable?

 

dan

[Ike]

Did you notice any differences in audio; damping factor THD etc?

 

I can live with a heavy amp that falls apart if you drop it :D

[pumphouse]

Could you give us soem idea of how many channels you need, and how much 'nothing' you have to spend? Also, some indication of the loudspeakers you have, and what the stolen amps are you are looking to replace might help us to provide you with more helpful sugestions.

 

I think there are things that can be scarificed for installation amps that don't get bumped on the road or dropped from aeroplanes, but these are more to do with robustness of build quality, rather than the quality of the electronics, performance, power regulation etc.

 

It sound like it isn't a critical listening application if it's for a club, so you may be able to scarifice some performance just to get you going again.

 

Was your kit insured? Worth thinking about for the future if not - then you can replace like-with llike (almost!)

 

Jason

[dan slv-tech]

Hi

 

Well To be honest for my FOH amp rack I still use Crest CA's, ive got 10Kw in 4 amps, weighs about 150kg, but its on wheels and goes in a 7.5 tonner so not an issue, I believe if its built sloid and indeed it may weight a bit, then it works, you dont find super lightweight pro mixing consoles do you?

 

for my MON rack I do use "cheap" far eastern amps, they are DARQ amps, and to be honest with you, they are a clone of the CA's, the only difference physically is the power switch on circuit, ive A/B'd the DARQ's against my CA18, and other than the fact that the DARQ's dont do a 2ohm load, id say performance wise they are pretty much the same, ive had a quick peep inside both and component wise, although the layout is much about the same the components are different, but then one was built 7 years ago the other about a year ago.

 

they however weigh the same.

Ive had QSC PLX's and had nothing but grief with them after a 4yr period, all had same faults (oscilation ciruit died) it worked out about £200 per unit to fix, in the end I found someone who took them off me for a song, and I got my crests, they work, theyre solid and sure they are heavy, but they havnt let me down yet.

 

on the cheap amp side, ive also tried ALTO MAC2.4 and to be honest they kick ass, I think its a case of if you get a good one its great, get a icky one and ur have nowt but grief- same goes for behringer kit!

 

I went down to DARQ in basildon and I thrashed the amps before I bought them, and I mean thrashed, so I was happy they could do what they said they could do.

 

any more details PM me

 

Dan

[paulears]

The pros and cons of Thomann 2400's have been covered a number of time - this thread being quite useful.

 

for an install - not at all a bad product - I'm a user adn very happy.

[dave singleton]

If its a case of you need the club up and running again asap then right now your best bet if you cant afford to buy decent, is to use the little money you have agree a long term hire program with a hire co. Then once the money is there buy them. I wouldn't skimp on quality especially in a club for the sake of being in the same situation 6 months to a year down the line.

[Rich]

I've had nothing but problems with the TA series due to mechanical failure from road use. Overheating, soundquality, they've been great.

 

I'm in Manchester too, if you want to borrow a T Amp for a demo, then you're more than welcome. PM me for my phone number.

 

Rich

[jayselway]

Cheap amps - hmmm

 

I guess it depends how they make it cheap. I had some DAP Audio amps, which were a great price, and £££'s for watts, very good. However, after about 6 months on the job, things start to go wrong - one of them, (Rich'll know about this one!) - the sensing circuit died, so even though it was still working, it may not have shut off in a fault situation, and the other one had one side just "let go" with a lovely purple wisp of smoke. It took out all the output transistors, the protection circuits (apparently where the problems started), and also two Tannoy cabs. It wasn't even a hard job - background music in a small bar - good ventilation, clean area, and no movement!

 

I have a t.amp in a bar at the moment, as a hire unit, and it's okay. It has it's moments, where it won't output anything, and just overheats - (again, background music only). At most other times it's fine! - Good thing that I'm putting the original (repaired) amp back in tomorrow really!

 

Personally, I wouldn't get another one - QSC, P.S.L. and Crest - never failed me once. *touches wood rather quickly*

 

£0.02

Jay :D

[Don Allen]

One of the reasons why "cheap" amps are so cheap, is that the design of audio amps is reaching a plateau as most companies have come up with reliable, stable designs which means that R&D costs are down so the selling prices are coming down.

 

The Asian copying and low manufacturing costs mean that their amps are very cheap because they are not paying any R&D costs.

 

The main design fault with the Asian amps is that they do not like touring as their design staff do not have the experience of touring failures so do not realise why good amps are overrated and their profit margin goes up if the shipping weight goes down.

 

For installs, there are some good, economical (perhaps a better term than cheap) amps but you need a word of mouth recommendation as there will be some cheap dodgy ones come out and those will end up in the bin.

 

If you have a reasonable budget or a need for a very reliable amp, you know you need to use the brand names.

[Furryface]

Without wishing to be flippant and not really help you, the answer to your initial question "What makes cheap amps cheap" is as follows.

 

1) Very, very cheap labour in China

 

2) Very, Very cheap component costs and shipping - all in China

 

3) Export Tax Credit from Chinese government.

 

4) Limited R&D

 

To give you an example, and this is a good 6 or 7 years back and things are even cheaper now, we worked out the component cost of a Behringer Composer plus labour at local China rates, price of packaging etc. The most expensive single part of the package was shipment from China to UK. Total cost of unit around £16, shiiping cost £8.

 

Go figure.

 

Not that relevant but interesting

 

Furry - a supporter of expensive UK (&EU) designed & built equipment

[Brian]

The Asian copying and low manufacturing costs mean that their amps are very cheap because they are not paying any R&D costs.

There's a nice irony here. When MOSFET amps first appeared on the market, all the UK makers were simply copying the design out of the 1981 Hitachi MOSFET Application Book rather than putting any effort into designing their own. And the stunts they pulled to make higher powered designs...

[jamesperrett]

There's a nice irony here. When MOSFET amps first appeared on the market, all the UK makers were simply copying the design out of the 1981 Hitachi MOSFET Application Book rather than putting any effort into designing their own. And the stunts they pulled to make higher powered designs...

 

I've got one of those amps - which is still going strong after over 20 years of fairly stressful life in a rehearsal room.

 

The big problem with cheap amps, in my limited experience, is reliability. I had a cheap amp before I bought the long lasting one mentioned above which started cutting out regularly just out of warranty - it seemed like a dodgy relay or dry joint because it could be made to come back to life again by a bit of mechanical force.

 

More recently we've been using high power amps for sonar work - the slightly more expensive QSC amps that we use now seem to be more reliable than the previous cheaper amps that we were using.

 

Cheers

 

James.

[Ike]

Sorry about not replying sooner and thanks to everyone who has PM'd me.

 

We have bit the bullet and purchased some TA2400s

 

After briefly trying them out last night with various bits of music and weird and wonderful bassy synth sounds we really couldn't hear any problems. For our money we also picked up a spare TA2400 and a couple of large rack fans to keep everything nice and cool. Hopefully that should keep us going for a year or two!

 

Thanks again,

 

Ike