ACD said:If you absolutely need more power and absolutely wants to use the Leach super amp, the best (and most save) way to get doubble power is to make two more Leach's and bridge them
Although I am a fan of the less grainy sound of bridge amps, you need to know that for driving a sub, the Damping factor of a bridge amp is half of the grounded version.
I have used +/- 100vdc pretty safely with Mj21195/96 however the heatsinks were windtunnels with thermally activating fans. It gets real hot!!
I got 500 wpc very easily with a 1kVA tranny. Used 8 pairs of the 21195/96 per channel. I did not try bridging this but one resistor and a wire would do it...
Also know this, I cannot explain it but my experience has shown that higher rails cause the sound to be come hard and brittle (other things being the same). How ever to get 500 watts in a bridge mode, all you need are rails of 60-65 and the sound will have less fatigue.
If you want to experiment just for the heck of it... go knock yourself out... I am sure most of us on the forum have done pretty stupid things in our days... just remember safety first!!
PS: The only OP devices for Audio that I know would survive 127v rails are the 4302/4281 devices... but beyond 90 volt rails, you need to paralell tons of them... like 10-15 pairs per channel!
Hi DJK,
I Checked the transformer before changing the grounding. Yes It's the some wire.. You can see that the wires are taken double to get the 12 Volt out. Otherwise the trick with the diode would be a great second. The transformer is a bit strange since It's called an R-core transformer (at least that's what I heared)Although I liked the Proton amp, I think the Leach sounds better. It's not as tweaked as the low tim amp so I might make one some day.
First I will start building a gainclone amp.
Michael
I Checked the transformer before changing the grounding. Yes It's the some wire.. You can see that the wires are taken double to get the 12 Volt out. Otherwise the trick with the diode would be a great second. The transformer is a bit strange since It's called an R-core transformer (at least that's what I heared)Although I liked the Proton amp, I think the Leach sounds better. It's not as tweaked as the low tim amp so I might make one some day.
First I will start building a gainclone amp.
Michael
Carver Lightstar
Hi All,
I used to service the Carver Lightstar series I. The rails were + / - 125V! The amp used down converters and idles at +/- 13V ish. These used to burn out the feedback resistor & pcb + outputs. Impressive.
At these voltages, when things go wrong ... they go very wrong in a hurry.
I used to own one too. Best sounding Caver amp ever. Sold it, my Marantz 300DC sounds much better.
-Chris
Hi All,
I used to service the Carver Lightstar series I. The rails were + / - 125V! The amp used down converters and idles at +/- 13V ish. These used to burn out the feedback resistor & pcb + outputs. Impressive.
At these voltages, when things go wrong ... they go very wrong in a hurry.
I used to own one too. Best sounding Caver amp ever. Sold it, my Marantz 300DC sounds much better.
-Chris
Re: Carver Lightstar
Do the rails on the OP devices ever reach 125v? I mean the switching MOSFETS are working at 125v but they only supply enough voltage to the 1302/3281 as needed. I'd say if they did supply the full +/- 125, they'd fry the Toshiba's.
Moreover I read Bob's tech papers saying that the MOSFETS were used as a Transconductance amp (???) that they convert the high voltage rails to high current need to drive 1 ohm loads. Just like the switching power supply in a car amp.
Also the lightstar was essentially an older version of the original Sunfire. (300wpc) I once owned the Sunfire Signature (600wpc) that was essentially a regular Sunfire but drove 2 ohms not 1 ohm, i'd guess in that the rails would go higher than in the Vanilla Sunfire/ lightstar...
K-
anatech said:
Do the rails on the OP devices ever reach 125v? I mean the switching MOSFETS are working at 125v but they only supply enough voltage to the 1302/3281 as needed. I'd say if they did supply the full +/- 125, they'd fry the Toshiba's.
Moreover I read Bob's tech papers saying that the MOSFETS were used as a Transconductance amp (???) that they convert the high voltage rails to high current need to drive 1 ohm loads. Just like the switching power supply in a car amp.
Also the lightstar was essentially an older version of the original Sunfire. (300wpc) I once owned the Sunfire Signature (600wpc) that was essentially a regular Sunfire but drove 2 ohms not 1 ohm, i'd guess in that the rails would go higher than in the Vanilla Sunfire/ lightstar...
K-
Holy Lightstar Batman
Hi K-amps,
Yeah, they would get within a volt of supply into an 8 ohm load. I never could test lower impedances as the shop breakers would trip.
The reason the o/p's didnt blow was that the voltage tracked the music signal reasonably closely, so you didn't end up with 250V across the outputs. Each channel was separate from the other. Two power cords etc.
The mosfets were high frequency switching elements, the duty cycle determined the supply voltage. They were in shielded enclosures on the sides. The top cover was the heatsink. It wasn't pretty when they let go.
As far as the timing of the two models were concerned, I guess Bob Carver would have to answer that. I was under the impression that the Lightstar was first, the Sunfire was Bob's answer with a smaller supply. The Lightstar II for a less expensive amp with a smaller supply as well. Vic Richardson at Carver was the major designer of the Lighstar if memory serves. A real nice guy who knew his stuff.
-Chris
Hi K-amps,
Yeah, they would get within a volt of supply into an 8 ohm load. I never could test lower impedances as the shop breakers would trip.
The reason the o/p's didnt blow was that the voltage tracked the music signal reasonably closely, so you didn't end up with 250V across the outputs. Each channel was separate from the other. Two power cords etc.
The mosfets were high frequency switching elements, the duty cycle determined the supply voltage. They were in shielded enclosures on the sides. The top cover was the heatsink. It wasn't pretty when they let go.
As far as the timing of the two models were concerned, I guess Bob Carver would have to answer that. I was under the impression that the Lightstar was first, the Sunfire was Bob's answer with a smaller supply. The Lightstar II for a less expensive amp with a smaller supply as well. Vic Richardson at Carver was the major designer of the Lighstar if memory serves. A real nice guy who knew his stuff.
-Chris
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