Zapco/BSG/Ebay deal

[chad]

I tore into the BSG amp last night and thought I'd share some thoughts and pics. I did not get to hear it because I was running late but did get a break out box built and took some static measurements.

Here is the bad Oscar:


And the preamp/ mic Pre/ CROSSOVER!



The amplifier runs on bipolar (duh) 14.8V rails. The power supply is a PWM switching type unit and is NOT cross-compatible for use in the car; it would be VERY difficult to convert. There is a switch in the power supply that I believe sets it up for 220V operation. Next to the power switch and HV rectifier, tucked in there is the Fuse, it's a 6.3A puck style commonly seen in European gear, they are not going to be found at rat-shaq so probe carefully, you will need to order spares from an electronics wholesaler like Mouser or Digikey. I plan to grab some in the next order I make, I'll get a part number.

The finals are 2N6488 and 2N6491 made by ST and Moto respectively. There is one each per channel; they are driven by TIP31 and TIP32 devices that are driven by Central CEN-U57 and CEN-U07 transistors. There is a lot of drive here with little gain, the amp should be pretty stout, the finals are 15A/80V devices so they are certainly running in their SOA.



The amp is fused at 6.3A the manual states that it can consume 420 watts, if the amplifier were 70% efficient this would mean that in theory, all channels driven, one could get 49W/Ch out of it, if it is 80% efficient (there IS a PWM supply) then theoretical output all channels driven would be 56 watts.

The manual states that it IS ok to run a 2 ohm load (they say 4 (X) 8 Ohm speakers per channel)

All this is only true if the power supply is up to the task, these are just figures. The HV pulse voltage of the PS is 166V, rectified and filtered right off the AC line. This is then pulsed and stepped down to the rail voltage previously mentioned.

Getting separate inputs...... My unit was sent with 2 audio cables, fortunately, after demolishing a PS/2 keyboard it was found that my specific keyboard did not have all 6 wires in it, just 4 and a shield. I chose to hack up ONE of the cables and save the other.


I used a small bud box and put 6 RCA females into it, I also installed 2 DPDT switches that gang channels 1&2 to 3&4 and 3&4 to 5&6, this way I can use 2, 4, or 6 inputs. I just did a pigtail end for wiring; I was going to not sacrifice a cable and put the jack out of the preamp in it but decided not to.

Here's the unwired box:



Breakout with the switches wired:


Totally wired:



Here's the finished product:



Big problems arose when becoming confused while looking at the manual for wiring color codes, the manual is screwed. They state the color coding as follows:
Ch1=Red
Ch2=Yellow
Ch3=Blue
Ch4=black
Ch5=White
Ch6= Black!!!!! (WTF)

2 blacks? and there is no white or blue!

Here's the correct wiring!!!

Ch1=Black
Ch2=Brown
Ch3=Red
Ch4=Orange
Ch5=Yellow
Ch6=Green

^^^^^CORRECT^^^^^^

Kinda looks like the resistor color codes eh? Whoda thunk it?

The second method of doing this eliminates the BOB and cable, you will need to drill 6 holes in the amp, I would do this under the speaker outputs, you will not need ground as chassis and signal share common ground. It does not render the stock input useless, it allows for an either/or operation.

IF YOU SUCK AT SOLDERING THIS METHOD IS NOT FOR YOU!

Near the female DIN connector you will see 6 SMT resistors labeled in this order:
R89
R90
R98
R105
R112
R116

See:


With a maximum of 1/16" chisel or screwdriver tip quickly tack 6 wires onto these resistors on the side closest to the input connector. GO FAST with the heat, too much heat will melt the other side and knock the resistor loose, they will re-attach but if you have never worked with SMT stuff it will anger you quickly!

The other ends of these wires will attach to the center conductor of the RCA's you just mounted. The order is as follows:

R89=CH3
R90=CH5
R98=CH1
R105=CH2
R112=CH6
R116=CH4

Now you have 2 different methods of inputting to the amp. Don't use both at the same time as the preamp won't like having signal applied to the outputs!


So there you have it!

Time for a reward!


Enjoy

Chad

[sqkev]

wait...how/when did I miss out on this?

so this is a home amp + preamp? is it fullrange on all 6 channels? how does it sound so far??

I'd be a great bedroom tester amp for me.

[chad]

For commercial use (resturant, etc)

6 channels 30W per at 4 ohms. 1-4 are HP'd 5-6 are LP'd at the control unit, the control unit has volume, bass, treble, mic gain and ducking. The amp itself is FR, I don't plan to use the preamp.

$42.45 shipped and it came F-A-S-T!

Chad

[sqkev]

so with your mod, you have 6 inputs and 6 fullrange outputs now? (for the loss of volume control right?)

How does it SOUND?

[rekd0514]

Dang we got some smart people here. Very cool! It looks a lot easier once you figured out all the work. haha Nice Work!

[chad]

Originally Posted by sqkev

so with your mod, you have 6 inputs and 6 fullrange outputs now? (for the loss of volume control right?)

How does it SOUND?

Yep, 6 in/6 out. Via switching I can par channels down to the point where I have 1 stereo pair coming in and 3 stereo pair out. Wiring the switches differently woulld allow for easy bridging without Y connectors.

I did not get the chance to listen to it yet, maybe tonight, it depends.

Chad

[azngotskills]

In your wired BUD box, is the ground of the PS/2 cable soldered to the chasis of the BUD box?

[chad]

Originally Posted by azngotskills

In your wired BUD box, is the ground of the PS/2 cable soldered to the chasis of the BUD box?

There's a ground lug included with each RCA female, I used one and tied the ground to that, the metal box takes care of the rest.

You can see it in the pic of the wired box, the ground is in clear heat shrink and tied to #1 (black on the PS/2)

I have tried to solder to a bud box.... it don't fly. they are aluminum and lead/tin solder simply will not stick, I tried real damn hard too

Chad

[~Magick_Man~]

i ordered my pair on friday, paid over the weekend and have heard nothing from the seller at all.

~Magick_Man~

[chad]

It will be there soon, via USPS, it made it here very fast.

Chad

[~Magick_Man~]

did you get a message from the seller letting you know they had shipped or did they just show up?

~Magick_Man~

[fej]

Hmm tempted. How much for the "chad" upgrade package?

[300Z]

I also missed on this...

Is this deal still available? If so, where? I need an small amp to replace my T amp and this seem like it would be perfect for my active setup...

Can it be bridged at all? 5ch would be awesome for my application.

Leo

[ca90ss]

Still available and yes it can be bridged.
http://cgi.ebay.com/ws/eBayISAPI.dll..._promot_widget

[300Z]

Awesome. Thanks!

[tyroneshoes]

Thats perfect chad.

Is there any way you can help a simpleton create one stereo input and two bridged stereo outputs and a bridged sub output?

Would you be willing to sell the switchbox/ps/2 setup?

[ArcL100]

Originally Posted by tyroneshoes

Is there any way you can help a simpleton create one stereo input and two bridged stereo outputs and a bridged sub output?

Would you be willing to sell the switchbox/ps/2 setup?

Ditto all that - that's how I'd be using it - and/or off the computer soundcard like the way scott_fx mentioned in the original thread. I honestly know nothing about this stuff (like what the hell a ps/2 cable is for starters lol), but bought one anyways, haha.

I'm not sure if my ratshack solderer is up for that kind of soldering anymore =/

-aaron

[chad]

Originally Posted by ~Magick_Man~

did you get a message from the seller letting you know they had shipped or did they just show up?

~Magick_Man~

Yes, I got a "payment received and will be shpping today" message. The seller is a very good guy and seems very honest. Shoot him a message.

Chad

[coffee_junkee]

Originally Posted by chad

Yes, I got a "payment received and will be shpping today" message. The seller is a very good guy and seems very honest. Shoot him a message.

Chad

Hey Chad, when you made your BO box, which wire is the signal ground for all the channels? I got the 6 color coded positive wires figured out, but the ground has me all tripped up.


IMO, this unit rocks! I bridged the four full range channels, hooked it up to my B&W 705 monitors and it sounded damn good. Plenty of juice to piss off the neighbors and my fiancee..

[chad]

Originally Posted by coffee_junkee

Hey Chad, when you made your BO box, which wire is the signal ground for all the channels? I got the 6 color coded positive wires figured out, but the ground has me all tripped up.


IMO, this unit rocks! I bridged the four full range channels, hooked it up to my B&W 705 monitors and it sounded damn good. Plenty of juice to piss off the neighbors and my fiancee..

There's a bare wire in there, it's a common ground for all channels.




See the wire going to ground lug the first RCA? (black wires connected) That's it! But I shrinked it in clear shrink tube.

Chad

[coffee_junkee]

Chad,

Ok, I'm an idiot and mistook that bare wire for plain shielding. Now, does that ground need to be split and soldered to all channel's grounds' or just channel 1? My BO box has no switches for bridging signals, just FR to all the channels.

Also, mabye you can clarify something in the manual that's somewhat confusing. It doesn't say exactly what each channel is capable of driving with regard to impedance. Is it 2ohm stable, stereo? The instructions mention that it's capable of four, 8ohm speakers in parallel..

Ugg.. My brain isn't working today. Need more coffee...

[STI<>GTO]

More information here --> http://www.pesupport.com/cgi-bin/config.pl?read=314066
and here --> http://xlobby.com/forum/viewtopic.ph...er=asc&start=0

Both several pages with some more good info. I also have a couple coming soon.

[chad]

Originally Posted by coffee_junkee

Chad,

Ok, I'm an idiot and mistook that bare wire for plain shielding. Now, does that ground need to be split and soldered to all channel's grounds' or just channel 1? My BO box has no switches for bridging signals, just FR to all the channels.

Also, mabye you can clarify something in the manual that's somewhat confusing. It doesn't say exactly what each channel is capable of driving with regard to impedance. Is it 2ohm stable, stereo? The instructions mention that it's capable of four, 8ohm speakers in parallel..

Ugg.. My brain isn't working today. Need more coffee...

2 ohms per single channel stable, have not tested output yet into 2 ohms. If your box is metal and you tighten the shit out of the connectors you will only need to attach to one point. If you want to install all the lugs and tie them together then knock yourself out

Chad

[chad]

Originally Posted by STI<>GTO

More information here --> http://www.pesupport.com/cgi-bin/config.pl?read=314066
and here --> http://xlobby.com/forum/viewtopic.ph...er=asc&start=0

Both several pages with some more good info. I also have a couple coming soon.

The cat in the first link has never dealt with "pre bridged amplifiers before" only "QSC" that is a pro amp.

If you do it like he says you will be grabbing 2 inverted channels and it won't work, you need to mono a PAIR (which is an inverted and non-inverted to do this. ONLY an even and an odd, not two evens OR two odds.

Yall are in the know how "pre-bridged" amps work right?

Chad

[STI<>GTO]

Originally Posted by chad

Yall are in the know how "pre-bridged" amps work right?
Chad

I didn't pay much attention to his instructions, as I don't have one infront of me yet, but to bridge you hook it up like most car amps right? For example: L+ and R-, or ch1+ and ch2-

Is that correct?