F4 power amplifier

[flg]

Originally Posted by Zen Mod

...it is , generally

I had the xfrmr connection in mind. As if the rest of the circuit were an F4

[flocchini]

[QUOTE=Zen Mod;3067691]link to xformer data ?


Electra-Print.com PVA Passive Audio Pre-Amplifier
Electra-Print.com Special Use Transformers

Sorry

[buzzforb]

FYI,
Guy in Swap Meet selling sowter mic input transfomers for very reasonable price of 20lbs.

[Zen Mod]

[QUOTE=flocchini;3067708]

Originally Posted by Zen Mod

link to xformer data ?


Electra-Print.com PVA Passive Audio Pre-Amplifier
Electra-Print.com Special Use Transformers

Sorry

no need to sorry

anyway - try to find some xformer with 1:1+1 ratio ,where primary impedance is marked for line level duty ( loading in range of 10K)

dual secondary (or one , center tapped ) is necessity , to have phase splitting function of xformer

tip - for better behavior in freq. domain , you can wire xformer as aoutoformer ....... in other words - as center tapped choke with multiple taps

dunno ..... on your side of Big Splash which xformers you can try

so - there is possible candidate , as example :
http://www.lundahl.se/pdf/1592.pdf

look at "Phase splitting 1:1+1 input " connection picture ; it's interesting for unbalanced to balanced conversion

in your case , as you already have balanced source , you can use it as 1+1 : 1+1 , where both primary and secondary center taps must be grounded , for perfect balanced function


conclusion - you can't use electra print , because of lack of dual secondaries ......... and low impedance primary

[flocchini]

Originally Posted by buzzforb

FYI,
Guy in Swap Meet selling sowter mic input transfomers for very reasonable price of 20lbs.

Thank you

[regal]

Originally Posted by flocchini

I have been listening to my balanced F4 driven by Pass X10 and fed by my Mc through a Buffalo II for about 3 weeks now. Running with 300mA bias at 15V.

I have to say this setup is absolutely superb with my HiFi Man 500s and with modded Denon 2000s, The bass is low and tight. There is very nice detail and the female vocalists (Etta James, Eva Cassidy, Jacintha, Nora Jones ) sound incredible. Why did I wait so long to do this. Highly recommended.

Thanks Choky and all who contributed to this thread/project.

I wonder what it would sound like with a MAGMA front end

Best

Bob

I have a pair of Hifiman HE-HLE (I think the sucessor to the HE-500), been following this thread as they need an unusual amount of power (~1=2W) for headphones.

I really think you will have a big improvement with a gain stage, no mater how big your F4 without at least a 6Vrms voltage swing these phones can sound better, at least for music with a bigger dynamic range.

Does the Magma include a VAS (or other gain) ?

[Zen Mod]

it was presumable that xformer , as connected , have gain in range of 14-15db

[regal]

Yes for the hifimans the lundhal 1+1:1+1 won't give the gain. A 1+1:1+1+1+1 may be a good compromise, just know from my experience with these ortho headphones perform best with 6Vrms swing headroom (measurements taken listening to my lowest level recording with the highest dynamics volume pot left in same position then running a 0dbs 1khz sine wave for measurement.) I've found typical recording listening level around 3-4rms (at 0dbs). Obviously most of the music content is lower but these thing want that headroom. They are rated at 87db/mW but I think at higher levels their efficiency drops. They are oddballs, but sound amazing and I've been considering the F4 buffer just for them (ethusiastic to see others thinking along the same lines.) Currently I am using a commercial hybrid + p-p mosfet output class A-B design.

[flocchini]

I have used a Aleph 30 with the HiFi Man 500s. Sounds extremely good.

In my opinion and I will continue to listen the balanced F4 driven by a Pass Xp -10 is right there with the Aleph 30.

I would like to try a Buffalo II with Volumite and Legato drive the F4 directly.

I am bit confused about transformers. Does the Lundahl 1592 have no voltage gain?
Would a Lundahl1674(1+1:4+4)http://www.lundahl.se/pdfs/datash/1674.pdf
have gain?

If someone could point me to a place to read more I will do my homework

Thanks

Bob

[Zen Mod]

numbers left are for primary windings , numbers right are for secondary windings

their ratio means voltage gain

you can wire LL1674 in several ways - just read datasheet and think

then ask