Difference between Forte 4 and 4A amp ?


Does any one out there know the difference between the Forte (Threshold) 4 and 4A amps ? Also, does the face plate displays the 4A model ? I just bought the Forte and the owner told me that it is a 4A model. However, the face plate and the back says it is a model 4. I am not sure what I got. Appreciate any help on this. Regards.
sas_quach
My 3's, 4's and 6's all ran at about the same temp give or take. The 4's should have been "warmer" in theory. All of these amps idle at about 115* - 120* or so and climb slightly from there when "gettin' it". Maybe my bias is up a bit on the "A/B" models. Should probably check into that.

The 3's actually sound slightly sweeter and airier ( but a little leaner ) to me than the 4's. Then again, my 3's were modified by Jon Soderberg of Vintage Amp. The 6's retain most of the sonics of the 4's but offer greater headroom and "oomph" in my opinion. Since most of my speakers are both low impedance and low efficiency, the bigger amps are a little more suitable to my situation. The 4's are QUITE beefy for "50 watters" though.

I ended up selling the 4's and kept a pair of 3's and a pair of 6's for use in a pretty big system that i'm working on. All four of these amps will be getting "tweaked" even more too far down the road.

My 1A actually ran noticeably cooler than all of these amps. That is, even though it was supposed to be "Class A" like the 4's. While it was noticeably lean sounding ( moreso than the 3's ), it also lacked the air and "sweetness" that i hear in the other Forte' amps. That is not to say that it is a bad amp, only that it was not what "I" was looking for. Who knows, maybe that one was slightly out of whack in terms of bias, caps partially drying up, etc.... Either way, the guy that got it absolutely loves it. His speakers were somewhat warm and he lives in an apartment, so he did not need a lot of "oomph" and the lean sonics complimented the rest of the system. A match made in heaven as far as he's concerned.

As to Brian's amp, it might have simply been a "lemon" or didn't blend well with the rest of his gear and various cabling. You would think that a pre / power amp combo from the same company would blend well together, but not necessarily so. Like anything else, it is all about system synergy and personal preference. That is why so many of us stress "in-home auditions". What floats your boat with your other gear might not float mine and vice-versa. Glad that he did find something that was to his liking though.

I've used one of my Forte's as a "loaner" on several occassions. Everyone that has used it has commented on how "sweet" it sounded. This with SS, or tube pre's including one guy running a passive. Somehow, everyone keeps using the same description ("very sweet sounding") of these amps without any coaxing or previous knowledge of them. The fact that they picked that single phrase, out of all of the audiophile terminology to choose from, tells me that there must be something to it.

As a point of interest, one of the 6's that i picked up had been previously repaired. The owner was not aware of this when he bought it. As such, he was not that thrilled with the amp, etc... and sold it to me. Once i got it home, I found the repair work and inspected the rest of the amp. The labor was done pretty poorly and using substandard parts. The amp ran much better once it was straightened out.

As mentioned, these amps sound MUCH better in terms of air, detail, spaciousness, etc.. after they've been on for hours and hours. If someone is turning these off and on as needed, they will never hear what they are fully capable of. I leave them on ALL the time for best results. Turning them off for an extended period of time "flattens" them out quite noticeably in my opinion. 24 - 36 hours after turn on, they should be pretty solid. I think that they sound best after about 3 days of continuous power though. All "high bias" amps appear to operate similarly to me. Amps that typically run "cool" or use digital / switching supplies don't seem to benefit from "continual on" nearly as much. Sean
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Sean, a couple notes of clarification and a small disclaimer. First the disclaimer, I am not being critcal of what all is being said here, I am just sharing my experiences.

Sean said, "As to Brian's amp, it might have simply been a "lemon" or didn't blend well with the rest of his gear and various cabling. You would think that a pre / power amp combo from the same company would blend well together, but not necessarily so. Like anything else, it is all about system synergy and personal preference."

I don't think it was a lemon for the fact that I had to send it in for repair at one time and I would think they would test it after the repair. As for not blending well with the rest of the system, I used many speakers, as stated, many CD players and two different speaker cable setups. When I installed the Meridian 557, changing nothing else, the system was MUCH better, it had much more low end, which was my biggest complaint for years, and the sound was improved in all areas.

"That is why so many of us stress "in-home auditions".

I did bring this home and try it before purchasing it. I had also brought home other amps before the Forte, this was the first to clearly outperform the amp I was using. Where I went wrong was, even though it outperformed the other, it still lacked the low end I would of liked. I bought it simply because it had more detail.
Your statements are completely valid and thanks for the clarification. I'm sorry if i came across as belittling.

While i would agree that none of the Forte's are "bass masters" and have previously stated so, i don't really consider the 6's to be "anemic" sounding. The 1's and 3's are leaner than the 4's and 6's in my experience. I have previously stated that these amps work best from a few hundred hertz and up. From your clarification, i guess you would probably agree.

My Classe' 70 was FAR leaner / brighter sounding than any of the Forte's that i've owned. As you probably know, Classe' amps are reputed to be "warm and smooth". We tried it in three different systems and had the same results each time. My Father found it so "painful" to listen to that he offered to hold the door for me so that i could take it out to the trash. Maybe that specific one was "funky". Who knows. Obviously components respond differently in various configurations and with different tastes.

As to the factory checking things out, i run into this all the time. Something measures fine but just doesn't perform "right". Kind of like when your car isn't running good yet everything checks out "okay" at the mechanic. So long as things are within spec, they probably won't dive in to find out what is "wrong". To them, there is nothing wrong because it is "up to spec". Tough to deal with sometimes, but part of life. Sean
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Thank you everyone for the inputs. I really appreciate it. It looks like I bought a model 4 amp since it does not balanced input. Anyway, I like the sound of this amp very much. The only slight negative is the bottom end. Also, I have been turning it on/off. I usually turn it on for an hour before listening. Based on most of your inputs, it sounds like I should leave it on constantly. I will try that next. Again, thanks. Regards.

Thong
Thong, i had to laugh when i initially saw your name ( Sas quach ) tied to this thread. Given my email address ( bigfoot1 ) and my liking of these amps, i found it to be too much of a coincidence.

As to the bottom end of this amp, i don't think that it is bad at all. Then again, that is simply my opinion and worth no more or less than anyone else's. I would leave the amp on and see how that works for you. If it doesn't give you what you want out of it, you might want to investigate into various cabling. Sean
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