PF 99 years of happines

[GoranB]

Hi,

I have built PF99 by Andrea Ciuffoli about 5-6 years ago, also his tube preamp which im useing like gain source. Durring these years i was changeing many other amplifiers, in general they were push-pull, but also tube amps.
After week or two, i was always conecting PF99 again to my system. I still cant find some amp which can "gave" more music then this design of Andrea.

I would like to exchange sound impressions (PF99) with people on this forum.

[arche13]

Good evening

I also have a pf 99, with préamp aikido with 6n1p and 6 o'clock 30,
In exit(release), my surrounding wall(speaker) of klipsch. Trés good sound
My PF99 is built with the original plan and IRF150N.
Your is he(it) built with the original plan?
What modifications have him(her) to bring you?
Cordially

[VladimirK]

Sometimes I see replies from PF99 builders, that they are not satisfied, in particular, not enough bass.
Good solution, confirmed by practice, for solving it - put 20pcs of 1000uF good quality caps, and decent polypropylene shunt to them.
Another point - an issue of the preamp. It must provide high sound quality with voltage amplification 20-30dB and low output impedance (tenths of Ohms in case of the PF99 based on IRFP150). I do not think these requirements are easy fulfilled by a tube preamp.

[arche13]

Hello Vladimir

It thus makes 20000µf by channel(canal), more the shunt of 50µf, what typifies of préampli it would be advisable?

[arche13]

Hello Vladimir

I am going to try soon with 6:30 am in SRPP it préampli!
Assembly(Editing) of internet with ra and rk 170 ohms assembly(editing) of Dilinhger

[VladimirK]

Originally Posted by arche13

what typifies of préampli it would be advisable?

I have tested and can recommend this preamp schematics, for PF99

No NFB Headphone/Pre Amp

[GoranB]

Originally Posted by arche13

Good evening

I also have a pf 99, with préamp aikido with 6n1p and 6 o'clock 30,
In exit(release), my surrounding wall(speaker) of klipsch. Trés good sound
My PF99 is built with the original plan and IRF150N.
Your is he(it) built with the original plan?
What modifications have him(her) to bring you?
Cordially

Hello arche13,

In my PF99 im using IRFP240
Current 3A per chanell
Voltage 34V regulated
Output capacitors SPRAGUE 4700uF/63V, bypassed with 16uF WIMA
PS capacitors -2 x 8200 uF/100V Nichicon
Two power transformers, one per chanell 34V/400VA
electrolitic caps in the circuit: 470uF/63V - Elna silmicII, 220uF/63V - Vishay low esr.
Ressistors are the ordinary cheap ones.

Vladimir gave me the same suggestion, cap-cluster, i still didnt try that mod. But for sure it will result with better sound.

My preamp:
gain stage: PCC88
catode follower: 12BH7
catode biasing of the gain tube - one red led.
output caps: 2x100uF/400V - Siemens (per chanell)
PS caps 4x68uF/385V - ROE, 220 uF/400V - Rubycon
AC heathed

The preamplifier is absolutely quet.
Sound warm, detailed, but kind of slow.

The best result with PF99 i reached, when i connected CD player output directly to PF99 inputs. Without preamp.
Vladimir designed preamp which could be implemented with PF99.
Thread: "NO NFB HEADPHONE PREAMPLIFIER" (something like that)
I have intention to build his design in near future.

Best regards

Goran