Suggest me a preamp for my F4!

Hello folks, I'm a happy owner of an F4 which I built a few years ago. I really dig it, and I'm using an Audible Illusions M3A preamp.

They sound amazing to me, together, but even if the M3A is well known for its high ouput, it still isn't quite enough to express the full potential of the F4. I find myself turning the knobs full clockwise, and sometimes it just isn't "enough", or other times it makes the preamp itself distort a bit too much. I'm a bit sad, because I really like it, but it just isn't as usable as I'd like...

So, taking advantage of some upcoming spare time, I'd be willing to build an adequate preamp to drive the F4 at its full potential.

I've done some research but I'm not sure, and I've been a bit out of the scene in the last couple years, and that doesn't help either; it looks to me like the Pumpkin Preamp is the best shot. Is that so, or are there any other serious competitors, well suited for an F4?

Price is a bit of an object here, but I don't want anything that will make me miss the Audible Illusions... So, I just want to build something good. I hope it's possible to find a project which is both good sounding and easy to put together...

Thank you in advance for your help ;)

Giacomo
 
I'm thinking the same thing with my Aleph4.

I don't want to introduce anything into the signal path that will destroy the beauty of my set up.

I am using an Arcam CD36 with a 100K Ladder Attenuator Passive Pre-Amp.

My idea is to build a VERY HIGH-END line amplifier but I'm hunting for ideas from the forums.

As far I can ascertain I won't go too far wrong with an AD797 Ultra Low Noise Op-Amp as long as I am very careful with layout and use a precision low noise power supply.

Pre-Amp designs other than RIAA designs seem to be very thin on the ground.

Any leads would be very helpful. NO TUBE DESIGNS PLEASE.
 

Marra

Member
Paid Member
2009-11-17 5:36 pm
Near Lincoln
Why not try Salas's DCB1 buffer. I've just built one for use with my Aleph 5 clone and it takes nothing away in fact the detail and dynamics are superb. As you are using a passive pre I don't think you would be dissapointed.




I'm thinking the same thing with my Aleph4.

I don't want to introduce anything into the signal path that will destroy the beauty of my set up.

I am using an Arcam CD36 with a 100K Ladder Attenuator Passive Pre-Amp.

My idea is to build a VERY HIGH-END line amplifier but I'm hunting for ideas from the forums.

As far I can ascertain I won't go too far wrong with an AD797 Ultra Low Noise Op-Amp as long as I am very careful with layout and use a precision low noise power supply.

Pre-Amp designs other than RIAA designs seem to be very thin on the ground.

Any leads would be very helpful. NO TUBE DESIGNS PLEASE.
 
Try Rod Elliot's P37A discrete SS preamp. I have one right now and it provides beautiful gain, crystalline-clear treble, and fantastic image precision. Don't expect warmth/relaxed presentation though. It is quite ruthless and will reveal everything.

It took me 2 hours to wire them point to point, and the components cost 5 bucks.
To date, it is the highest perfoming, lowest cost preamp I have ever seen. No need for audiophile parts.
 

juma

Member
2005-11-08 11:27 am
Zemun
Try Rod Elliot's P37A discrete SS preamp. ....

That's a nice suggestion :up:
When I was interested in F4 I tried that preamp too. I modified it to use the F4's PSU. I also excluded input buffer from F4 (complementary JFET buffer doesn't sound right to me) but I added an EF on preamp's output to drive the F4 with ease. Gain is 20dB (10V/V), Iq was about 25mA (set with P2) and DC offset is set with P1. Q5 and Q6 need heatsinking (an old CPU heatsink from PC per channel will do the job). Max. output swing is about 22V peak which will drive F4 to full power. It sounded good untill F5 came along... ;)
Here is the sch.:
 

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Marra

Member
Paid Member
2009-11-17 5:36 pm
Near Lincoln
I've built both the standard B1 running on 18v batteries and the Salas DCB1 which;with no disrespect to Nelson; is a big leap forward in sound quality in my opinion and works extremely quietly with its shunt regulated supplies. It is on loan with a friend at the moment and he keeps emailing me extolling its virtues.
I'm not knowledgeable enough to answer the technical questions.
Sorry Giacomo this has nothing to do with your original post.:rolleyes:



QUOTE=Andy5112405;2311017]I've studied the B-1.

With no global feedback, how does the pre-amp control its gain ?

Also would the design be severely compromised using an LM317/337 based PSU with follow on shunt quieting ?[/QUOTE]