Im considering buying a Forte model 3 amp, but for some reason they are a lot more expensive on the used marked than the 1A...
I have been reading a bit about some of you converting the model 3 to 1A, but have not seen any mentions on the other way around.
Is it possible, and is it a difficult operation? What kind of equipment do I need for this?
I have been reading a bit about some of you converting the model 3 to 1A, but have not seen any mentions on the other way around.
Is it possible, and is it a difficult operation? What kind of equipment do I need for this?
Is a transformer problem , AB have a lot Voltage and low bias current ,class A a lot af bias current and low Voltage
Price in the used market is not a compelling reason to change the amp, IMO.
To actually answer your question, yes is it possible. Difficulty is relative. Not that it's really our business, but why would you want to do that conversion? That might allow a bit more creativity in suggestions re: whether you'd leave a 1A alone, do a 'partial' conversion, or go full-monty.
There's a pretty good reason (IMO) you did not see people converting 1As to 3s. I'd suggest that if you find a 1A at a cost you're willing to part with, buy it and use it. If you find a compelling reason to change it to a 3, you'll have a lot more to go on re: what you really want. My guess is you'd leave the 1A alone.
from k-amps user:
"(Nelson can correct me on this) but like the Models 1 and 3 which were the same amp just wired differently (one a 50w class-A, the other a 200w class AB). Same chassis/sinks/circuits/caps etc
In the Model 3, NP had 45v caps running in series (as 90v's) on 78 volt rails. In the Model 1 (1a?) he wired the Trafo in series to get 50% voltage... with that you connect the caps in parallel and bias it high and Voila, you have a 50 watter class A with 39vdc rails.... using 45v caps. Again same caps as 200 watter just wired parallel vs. series."
"(Nelson can correct me on this) but like the Models 1 and 3 which were the same amp just wired differently (one a 50w class-A, the other a 200w class AB). Same chassis/sinks/circuits/caps etc
In the Model 3, NP had 45v caps running in series (as 90v's) on 78 volt rails. In the Model 1 (1a?) he wired the Trafo in series to get 50% voltage... with that you connect the caps in parallel and bias it high and Voila, you have a 50 watter class A with 39vdc rails.... using 45v caps. Again same caps as 200 watter just wired parallel vs. series."
I love the sound of class A amps, but I have speakers difficult to drive, a pair of Infinity Kappa 9.2i and therefore I need a powerful amplifier that can deliver a lot of current and be stable at 1.3ohm. The second issue I'm not sure of if those Forte amps are capable of, but I fear that the class A version will not be powerful enough to drive my speakers properly. But I am not any expert on this matter and I don't have only a limited understanding on how this works. Its just a thought, 50w/channel compared to 200w/channel on power hungry speakers...
I have a Forte Audio 1A that I'm not using if you're considering trying one out as-is or with the conversion to Forte 3. Only issue I've had with it is the bias potentiometer in one channel will "let go" when it hasn't been powered in a while, resulting in no bias in that channel. It's a quick fix to open the case turn the pot a couple times and re-bias.
