awesome, can't wait to see a shootout
I have a friend just down the road that has a pair of stock Forte's I think its time again for another serious comparison as its been awhile since I've had a stock pair here and I haven't done a side by side comparison since these last up grades it should be interesting so I'll see as to when I can get them here :yes:
I had been holding out for a Klappenberger Forte network for a while before I gave in and did the complete crossover makeover this thread is in regards to. But even if it's a while down the road before a network appears, the prospect that the parts I've already acquired would be re-used is a relief.
What really sold me on the Forte was not just that it mated well with tube amplifiers and could deliver effectively for a variety of musical genres, but that it is well-balanced, has considerable bass response and a very good sensitivity rating. So there's many reasons to want to push it to the limit. And one feels even more compelled if they're into DIY.
When I'm finished with my next three projects I'll have a refurbished/replinthed Lenco turntable, a kit-based phono pre-amp and a kit-based line stage as well. That's a lot of critical listening to perform on components with substantial time invested in them, so the Fortes were the logical first step towards an eventual progression of (hopefully) well-balanced, quality builds.
As an aside, I wanted to mention how much I like the EH 6CA7 fat bottles in my modified ST-70. Before the Forte makeover I found them thin and lacking extension and preferred the robustness of the Winged =C= EL34s and the warmth of the JJ KT-77s. With the extra clarity of the new crossovers, the 6CA7s have dynamic, balanced sound that leaves little to be desired.
Looking a long way down the road and the eventual DIY monoblock project is going to be a lot of fun...
-Brinkman
I just might have to contact Al.
Yes, I to like the EL34 family and the 6CA7's.
What were you thinking of for a mono block project?
Also would you care to try a little experiment?
Would you like to hear the Punch Factor of you amp go up?
Yank out that choke or put a jumper across it!
I myself don't use them cause of the usually high DCR 100 ohms is very audible and I would think 60 ohms would be to! Which is the dyna's stock DCR value.
If I were using a choke it would likely be lest than 20 ohm's like
Herb Reichert here, just read about the sheer current reserve he uses!:yes:
Its my next step!
http://www.enjoythemusic.com/magazine/equipment/0801/fleshandblood.htm
Since the amp is PP you shouldn't have to much of a signal to noise increase and if you liked what you heard but wanted it a little quieter you can just add more capacitance. I assume your using a slow turn on rectifier like the 5AR4, and as you probably know newer versions have not been meeting the slow turn on spec so NOS is best.
I like to use Diodes to drop supply noise over in my B+ supplies. I also use electrolytics as bulk then branch off with another diode to feed Solen Poly Props the diodes highly isolate the Solens in my SET mono's each of which run on 1800 uf of electrolytic bulk then feed to 22uf of Poly Prop for the output stage (when I think about it I might increase it) and 12 uf for the driver stage. Can you say nil for DCR? I can
Which is part of the reason that the Forte's here do have a leap factor.
Usually a supply this big does not sound to good. But even with this much electrolytic it sounds like a literal prop supply. Very very transparent.
I do feel compiled describe my amps a bit simply because they are contributing to the Forte's.
Also I use the C4S current source loading for the driver stage which can lower the distortion vs a resistor plate load to as much as 300% lower. Also I don't bias with resistors I use LED's I can thank Dennis Had of Cary Audio for that trick!
And the last trick since my amp runs in Class A2 it is design to run on "0" volts bias and knowing the effect of resistors vs LED's I used a pair of diodes to connect the directly heated triode filament to ground. The punch factor increased so much from this connection that I got a call from my duplex neighbor that her pictures where moving on her walls! That was with two garages between our living rooms.
So these are some very powerful SET amps and its important to know that ones mileage will vary from these Forte mods with associated gear but I'm sure you all very much know this!
This hobby sure is fun!
SET12