Anyone know anything about this amp?

MikeHunt79 · 7th May 2008, 06:36 PM

I pick this up for next to nothing today, I only really need it for the chassis anyway, but I've tested it and it works, so I wouldn't mind know a little more about it if possible....

Front:

Guts:

On the back it looks like it's made by:

"D J CONTRACTS
RYE
EAST SUSSEX
+44 01424 882636"

The power caps are rated for 50v so I can't imagine it having much power for a PA amp, I was told it does 280w which I took with a large pinch of salt...

Anyone know anymore about it at all? It's almost as if someone was selling DIY amps as it looks totally DIY!

gareth · 7th May 2008, 07:00 PM

That's low-end semi-pro for you. Good move with the casework though.

Gareth

MikeHunt79 · 8th May 2008, 01:13 AM

^ Yea I evetually plan to put a much better amp in the case. I may keep the guts of this one tho as a backup tho as it's a shame to throw out a working amp.

jaycee · 8th May 2008, 07:19 AM

Looks like a fairly basic MOSFET amplifier, probably similar to the old Hitachi note, judging by the parts count in each channel. I'd have said MAYBE 200W per channel into 4 ohms, but the lack of heatsinking other than the case make me think that it'd probably expire fairly quickly if you tried it!

Looks like theres some good quality parts in there though. It'd make a nice home for a 100W/8 ohms amp. See if you can work out what VA rating the transformer is. If there's a fuse on the primary side of the transformer, it might provide a rough idea.

h_a · 8th May 2008, 07:27 AM

200W from a single output pair? More likely half of that.

By the way, nice to see somebody using the nice Toshibas.

Whats the longish part to the left (behind the cap)? Looks a bit like a dual part.

All the best, Hannes

AndrewT · 8th May 2008, 12:30 PM

I'd suggest +-45Vdc for the supply rails to those Vfet outputs.
This will give you a nice 70W into 8r0 amplifier.
Add a decent heatsink to keep them cool.
If the transformer is of too high a voltage, remove it for another project.

BTW,
I'll guess the 280 in the ref no. is the sum of the maximum transient rms power into both channels. i.e. 140W into 4r0, 10% duty cycle @ 10% distortion.
Which might just equate to 70+70W into 8r0 @ 10% distortion. or 60W+60W into 8r0, 0.5% distortion.

Take out those 2off 4700uF caps and replace with 4 off 10mF caps, thus increasing the smoothing by a factor of four. +-20mF is ideal for a single channel feeding 8ohm speakers.

7th May 2008, 06:36 PM	#1
MikeHunt79 diyAudio Member Join Date: Aug 2003 Location: Bristol, UK	Anyone know anything about this amp? I pick this up for next to nothing today, I only really need it for the chassis anyway, but I've tested it and it works, so I wouldn't mind know a little more about it if possible.... Front: Guts: On the back it looks like it's made by: "D J CONTRACTS RYE EAST SUSSEX +44 01424 882636" The power caps are rated for 50v so I can't imagine it having much power for a PA amp, I was told it does 280w which I took with a large pinch of salt... Anyone know anymore about it at all? It's almost as if someone was selling DIY amps as it looks totally DIY!

8th May 2008, 07:27 AM	#5
h_a diyAudio Member Join Date: Sep 2006 Location: Graz, Austria	200W from a single output pair? More likely half of that. By the way, nice to see somebody using the nice Toshibas. Whats the longish part to the left (behind the cap)? Looks a bit like a dual part. All the best, Hannes __________________ fresh matched IRFP240/IRFP9240 fets \|\| AlephJ/JX-kits F5 transistor kits \|\| Burning Amp BA-1/2/3 transistor kits

8th May 2008, 12:30 PM	#6
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	I'd suggest +-45Vdc for the supply rails to those Vfet outputs. This will give you a nice 70W into 8r0 amplifier. Add a decent heatsink to keep them cool. If the transformer is of too high a voltage, remove it for another project. BTW, I'll guess the 280 in the ref no. is the sum of the maximum transient rms power into both channels. i.e. 140W into 4r0, 10% duty cycle @ 10% distortion. Which might just equate to 70+70W into 8r0 @ 10% distortion. or 60W+60W into 8r0, 0.5% distortion. Take out those 2off 4700uF caps and replace with 4 off 10mF caps, thus increasing the smoothing by a factor of four. +-20mF is ideal for a single channel feeding 8ohm speakers. __________________ regards Andrew T.

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7th May 2008, 07:00 PM	#2
gareth diyAudio Member Join Date: Jan 2008	That's low-end semi-pro for you. Good move with the casework though. Gareth

8th May 2008, 01:13 AM	#3
MikeHunt79 diyAudio Member Join Date: Aug 2003 Location: Bristol, UK	^ Yea I evetually plan to put a much better amp in the case. I may keep the guts of this one tho as a backup tho as it's a shame to throw out a working amp.

8th May 2008, 07:19 AM	#4
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	Looks like a fairly basic MOSFET amplifier, probably similar to the old Hitachi note, judging by the parts count in each channel. I'd have said MAYBE 200W per channel into 4 ohms, but the lack of heatsinking other than the case make me think that it'd probably expire fairly quickly if you tried it! Looks like theres some good quality parts in there though. It'd make a nice home for a 100W/8 ohms amp. See if you can work out what VA rating the transformer is. If there's a fuse on the primary side of the transformer, it might provide a rough idea.

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