BGR Blazer X10 1000W RMS Monoblock Power Amplifier

[sifis_samos]

Hello there. Guys has anyone tried to build such a powerfull ampo, not for a specific reason but just for the fun of it?!,recently i was looking in ebay and saw this:
BGR Blazer X10 1000W RMS Monoblock Power Amplifier DIY

BGR Blazer X10 1000W RMS Monoblock Power Amplifier DIY - eBay (item 150371286906 end time Dec-05-09 23:51:03 PST)

Using high quality SANKEN 5x 2SA1295 & 5x 2SC3264 ... it looks neat and,well the cost isnt that super and i was just wondering how it might play , with a really powerfull PSU. i do have a large box from a friend with 2 LARGE side heatsinks, and i was thinking of building it. everything seems quite easy since pcbs are pre assembled..Any comments are welcome.

[nigelwright7557]

Seems a good price.

The problem with these amp modules is the price looks good but by the time you factored in heatsink, huge transformer and a case the price has rocketed.

[sifis_samos]

well i do have the proper box, with a HUGE heatsink measuring 50cm x 21cm height, on each side, and thats why i was thinking about it.,..as for the torroid how big it might need?..somewhere around 1000VA each chanel is ok i guess right?..i may make a phonecall to know the price for 2 nice torroids..
I am mostly concerned on what should i take really good care of, as 1000W arent a small deal and i dont want to endup with a burned module..

my box is this one:

www.modushop.biz/ecommerce/05500028_0000.jpg

1x Frontal Panel in aluminium 10mm oxidised black 450 mm
1x Back in metal painted black anti-scratch
2x Lateral Heatsink oxidised black C°/W 0,11
2x Covers in metal painted black anti-scratch
Width: 450mm internal 360mm
Depth: 500mm Internal height: 210 mm
Weight:: 18,0 KG

from modu.it

i actually got it as a gift..

[picowallspeaker]

Hi sifis samos.Was it you that built the preamplifier kit ?
If yes , did you succeed ? And how does it sound ?
Not really concerned , just to keep in touch..
Bye

[nigelwright7557]

Given 40% of power is lost in heat then you would need a 1400VA transformer each side to realise full power.

You might want to consider DC detect drop out relay and power on surges.

[ostripper]

I agree , if the OP devices are not fakes .. a VERY good price.

2 issues stand out with this package , actually 3 , but the 3'rd is understandable.(ip issues)

1. NOT 1kw - 5 pairs of those sankens do not even come near the SOA (attached below) to do 1KW... About the same SOA as 21193/4's.
300w continuous , maybe 1kw 10ms pulse (4R load ... maybe )
2. The circuit , while it would work , is not too refined for a amp of this caliber. Running the VAS at 10+ma and just using a low HFE type1 EF would make this amp perform horrible with a demanding load. It is similar to my "supersym" (cascoded LTP , same VAS, outputs as drivers) but very amateurish in its design. Also the VAS to-126 devices will be very hot as designed with no heatsink. The OP device drivers should have been on the main HS and he should have used a triple OP , this is why .47R emitter resistors are used .. bad thermal stability.

the 3'rd - Schematic is wrong (cascode is biased wrong).
At $5.00 apiece for the sankens , the package is a deal , but makes me wonder .

OS

[nigelwright7557]

Originally Posted by ostripper

1. NOT 1kw - 5 pairs of those sankens do not even come near the SOA (attached below) to do 1KW... About the same SOA as 21193/4's.
300w continuous , maybe 1kw 10ms pulse (4R load ... maybe )

OS

Output transistor power dissipation is quite complex.
1/ Typically the output transistors take 40% power and the load 60%
2/ The output transistor is only on for 1/2 cycle.
3/ The power dissipated on a half cycle rises to a midway voltage then declines after that to the power rail.

[ostripper]

I agree , it is, but this amp is overrated. The designer seems to have just multiplied the device dissipation X5. The "brother of quasi" with 4 pair of MJ15024/5's is only 300 watt. My amp with 5 pair 21193/4's is 300+ at best.

The only true 1KW project I have seen is ESP's "insane" project 117 ... Project 117

9 pair 15024/5's or MJW21193/4's , along with a proper triple to prevent beta droop with difficult loads. (attached)
OS

[sifis_samos]

Originally Posted by picowallspeaker

Hi sifis samos.Was it you that built the preamplifier kit ?
If yes , did you succeed ? And how does it sound ?
Not really concerned , just to keep in touch..
Bye

My friend i am still waiting for the corect torroid as they sent me a wrong one.. i will update for sure at the topic i started!..hopefully this coming weekend i will have it ready as the shop i ordered the torroid said i will have it tommorow..

[sifis_samos]

hmm..the overal conclusion that i get is that this doesnt seems as a very good project..i dont want to spend much on something that perhaps is badly designed..

What about this one using 4 x TDA7293 ?...

350W Mono TDA7293 BTL + NE5532 Power Amplifier Kit -New - eBay (item 260507616840 end time Nov-25-09 19:46:25 PST)

pros?cons?...
I do want to build something powerfull. i always wanted!...since now i am very satisfied by my Gainclone so i want something else to play with!!..