esp project 101

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Ex-Moderator R.I.P.
Joined 2005
I have got the impression that laterals wont work well with F5
Tho, I have thought maybe if I use slightly lower voltage, and beat them with a hell lot of bias current
I have exstremely large heatsinks for that
I also thought about using an interstage tube trafo, but I have no idea how
or maybe the new grid choke from Lundahl
With the "isolation" of Jfets from output stage, it might be possible to experiment with power supply to jfets, maybe

Anyway, lacking the needed skills I thought maybe better build F5 with a single pair Toshiba
Im not into F5 for monster power
Better ways to achieve that
I decided to go for optimum quality, with the F5, keeping it "simple"

but nice of you to notice, thanks:)
Im still open to suggestions
I also have 8 pair MJL which could be used with these monster trafos
 
Hey, I might choose to build this amp
reason, I have two monster trafos, 2x 38V/25A
...
Any reason not to ?
Hi Tinitus,
you already know that P101 (hi power version) require 2x50V on trafo sek.
Maybe not a problem for you... ;)

To Paulo PT:
It's "only" AB class amp but sounds great. Can't compare with Nelson's (& other A Class) amps, because haven't that experience yet.

As paulb said:
"The P101 is easy to build and sounds great, no reason not to build it."
Additionally: not very expensive to build either...
:cheers:
 
Last edited:
Ex-Moderator R.I.P.
Joined 2005
Bora
those designs looks a bit complicated, but thanks anyway

ma-coule
2x 50Vac is recommended max voltage

simpler one pair version is supposed to work with as low as 25V+/-

and thanks for the encouragement, I need it :D
anyway, I have Lynx boards to match the MJL devices
I suppose they may have to go(sell) together


Hi Tinitus,
you already know that P101 (hi power version) require 2x50V on trafo sek.
Maybe not a problem for you... ;)


As paulb said:
"The P101 is easy to build and sounds great, no reason not to build it."
Additionally: not very expensive to build either...
:cheers:
 
Ex-Moderator R.I.P.
Joined 2005
Great to hear that

well, my "small" trafos will have to do :D
 

Attachments

  • IMG_0824 (Large).JPG
    IMG_0824 (Large).JPG
    68.6 KB · Views: 610
Hey, I might choose to build this amp

reason, I have two monster trafos, 2x 38V/25A...............
also have 4 big heatsinks ....
starting with the transformers.
those secondaries should be capable of ~150W into 8ohms or 300W into 4ohms or 600W into 2ohms. I would not consider trying to achieve 1200W into 1ohms.

But that 600W into 2ohms only uses ~30% of the capability of the 1900VA transformer.

Either two 600+600W into 2ohm amplifiers could be built (4channels & 4 heatsinks) or consider a pair of balanced amplifiers (same as bridged but designed from the outset to use balanced as an asset rather than brute power.

The 300W into 4ohm half amp becomes a 600W into 8ohm balanced amp (two of these could run off each transformer still giving 4channels in total) or the 600W into 2ohm becomes 1200W into 4ohm and you get two 1200W monoblocks.

If your heatsinks are big enough and you had double the number of output devices you could think about a high bias ClassAB design but set to optimum bias rather than overbiased.

OOPS,
optimum bias only applies to BJT output stage.
Your Laterals just need lots of bias, maybe 500mA per amplifier.
 
Last edited:
Ex-Moderator R.I.P.
Joined 2005
those secondaries should be capable of ~150W into 8ohms or 300W into 4ohms or 600W into 2ohms.


OOPS,
optimum bias only applies to BJT output stage.
Your Laterals just need lots of bias, maybe 500mA per amplifier.

thanks Andy
yeah, I like low ohm stability, more than monster power into 8ohm :)
and Im not really a "fan" of balanced, though tempting

heatsinks
I have 4x 300x200x40

just tried to order board from ESP, 10 minutes ago
 
low ohm stability is not the same as low impedance driving capability.

A 2ohm capable amplifier must be able to drive a 1r0 load without damage.
I would suggest it should even be able to drive a 0r6 load without current limiting and that it should still have adequate voltage drive into that resistive test load.

That is quite different from stability into 1r0 or 2r0 or 2r0//100nF or etc....
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.