Difference between Forte 4 and 4A amp ?

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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NEWSFLASH: A rehash of old info that pertains to this new thread about old gear : )

I was digging through some audio rags and ran across some information that might explain some of the variances regarding these amps. Moncrieff of IAR stated that the majority of the Nelson Pass designed Threshold amps were quite load sensitive. As such, changing speakers and / or cables could change tonal balance to a very noticeable degree. Depending on the impedance / type of load that the amp was seeing, the tonal balance could swing one way or the other. Since Nelson designed the Forte' amps, i would imagine that much of this syndrome carries over to that product line also.

According to what "J. Peter" had to say, these amps could sound bright and thin if used with speakers that were relatively resistive by nature ( non-reactive ) and / or had a relatively higher average impedance. Going to a speaker that was higher in reactance and / or lower in impedance would tend to bring the amp closer to a flat response or even towards the warm and rolled off side of neutral. I think that THIS explains a LOT of what we might be encountering with these amps.

Since most of my speakers are of lower impedance than average and generate a relatively high amount of reflected EMF due to large motor structures ( making them more reactive than resistive ), one could see how i might hear them as being relatively well balanced & smooth but still lacking in extreme bottom end. Hooking them up to speakers that were nominally 8 ohms or so and resistive might give me similar results to what others have already commented on.

So, in plain English, EVERYBODY is "right" on this one. Given the variables with all of our experiences and selection of speakers / cables / support components, these amps could end up creating quite a varied response from user to user and system to system. This goes to show just how important it is to check a component in YOUR system when striving for the ultimate in "system synergy".

With all of that in mind, it kind of confirms what cables i've found to work well with these amps. For the record, i've always liked Goertz the best with these amps. The fact that they are highly reactive ( capacitive ) by nature and offer a much lower nominal impedance ( about 2-4 ohms ) than most other cables somewhat confirms what Moncrieff stated. Chris VH's 27 pair Teflon CAT5 design actually gave me the most bass foundation, but i found the Goertz to be quite a bit more liquid in the mids with more air and detail up top. Since both of these cables are capacitive and could cause wide bandwidth amps to oscillate, i would recommend the use of Zobel Networks should someone else choose to use either in their system. Other speaker cables that i've tried in this system are Kimber's, XLO, Audioquest, Axon, Monster, YBA Diamond's, etc.. and various home-brew designs. While some sounded notably better than others, the Goertz are still hooked up in this specific system.

Hope this helps and explains some of the variables that we've encountered along the way in this thread. I would be curious as to find out if the other "fans of Forte" are using low impedance / reactive speakers and what type of speaker cables that they are coupled to. Sean
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For the record, I stated this above, but in lieu of Sean's comments, here is the speakers I used with the Model 6.

* Mirage M3's
* Linn Keilidh's
* Linn AV5140's

Speaker cables:
* Audio Quest Midnight for lows and Cardas Quadlink 5 for mid/highs.
* Linn K400

If what Sean says is true, I have no reason to doubt, it would cause me to shy away from such a touching product. It sounds by the comments from others, that it can be a nice sounding amp under the right conditions. As with Sas_Quach, I too suffered from very little low end.