FirstWatt J2

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R

rickmcinnis

Member
Joined 2006
Life with J2

saw a post on this thread and thought I would add my latest thoughts.

I have found the amps and all of the changes I had to make to use the (now single) amp have taken awhile to settle in.

I guess I have had the amplifier about two months. Last night, even though it is bitterly cold here and I have found dry cold to not be conducive to the best sound, all started sounding very good. Not that the amp ever sounded less than good it is now becoming a prized possession.

When I think of the value this amp offers I would suspect this one will remain a product within the FIRST WATT line for many years. No one would be happier than I if Mr. Pass finds a way to make it sound substantially better but this seems to me to be a classic product.

I would not expect to see the schematic shared anytime soon. Make life easy on yourself and just buy one! I do wonder how much money one could save doing themselves in this case.

Out of curiosity has anyone out there detected an area of improvement for the circuit? One can ponder whether fancier PS caps could make a difference and certain positions could benefit from boutique resistors, though I would be hesitant to try this out for myself.

Cordially,
 
H

HVfanatic

Member
Joined 2008
Hi Rick,

I have quite good equipment (omtec ca 25, audiostatic es300...)

but: Unfortunately, this would only return a small amount when sold...

So I'm still in hope that Nelson will share his secrets... ;-)

But yes, you're rigt, it's woth its money..

But before I buy one, I will get a second hand X2 pre... ;-)

Dirk

P.S.: Nelson, what are your personal plans on the subject???
P.P.S.: Maybe I should build an Circlotron amp with the semisouth???
 
Phil Townsend

Phil Townsend

Member
Joined 2004
J2 and "High End" parts

Good design trumps expensive parts.
That said, IMHO, different parts will sound different!
More expensive parts will sound different!
But will it sound better?
Better than what?
To me, I like to voice amps to suit my own taste.
But for the J2...
I like it... as is.

For others... light up the soldering irons and go to it.

Phil
Not at CES
Santa Fe
 
H

HVfanatic

Member
Joined 2008
I'm also really impressed by the firstwatt siplicity. I really admire the F3 for its design, and I like the J2 even more, because it lacks any cap in the signalpath.

I'm really awaiting Nelson to publish his schematics...

Maybe Nelson creates an J2a, using circlotron topology - and explains to us the steps of optimization... ;-) I would also be very interested in the question, how he found the optimum ratio of the shunt resistors... Does he use 2 currentsources to feed the voltage reference, or just a single one???

I'm so impatient...

Dirk
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
rickmcinnis said:
saw a post on this thread and thought I would add my latest thoughts.

I have found the amps and all of the changes I had to make to use the (now single) amp have taken awhile to settle in.

I guess I have had the amplifier about two months. Last night, even though it is bitterly cold here and I have found dry cold to not be conducive to the best sound, all started sounding very good. Not that the amp ever sounded less than good it is now becoming a prized possession.

When I think of the value this amp offers I would suspect this one will remain a product within the FIRST WATT line for many years. No one would be happier than I if Mr. Pass finds a way to make it sound substantially better but this seems to me to be a classic product.

I would not expect to see the schematic shared anytime soon. Make life easy on yourself and just buy one! I do wonder how much money one could save doing themselves in this case.

Out of curiosity has anyone out there detected an area of improvement for the circuit? One can ponder whether fancier PS caps could make a difference and certain positions could benefit from boutique resistors, though I would be hesitant to try this out for myself.

Cordially,
Click to expand...

if you're talking about exact ( J2 ) amp improvement ....... usual things :

entire PSU(s) dual mono , shotky bridges , even more Pana's for one channel then it was for stereo , 50uF Motor Run caps as bypass per each PSU leg .

I have impression that circuit itself can hardly be improved ...... without making entire new amp :rofl:

just be sure that you find best speakers to mate with amp ...... that will be most prominent tweak .
 
R

rickmcinnis

Member
Joined 2006
An honor: my humble post was noticed

by ZEN MOD!

If I knew 1/10 of what you know I would be (even more) dangerous.

My speakers are high efficiency and the J2's duties begin at 75 hz.

The amp gets just above warm (my room is 57 degrees F.).

A very easy load, I would suspect.

Using TAD 4001's above 500 Hz and have never heard them sound ethereal before.

Your suggestions for the supply are, of course, hard to argue with but one can also wonder if in my case one could add too much capacitance? I just might screw up my courage and do the BIG bypass, though. That makes good sense and would be relatively easy to do.

Just installed a SIGNAL DU-2 isolation transformer and was surprised how much better the sound became. I live in the suburbs and assumed my power was relatively clean. All of a sudden details, they were there before, but now they have a closely defined space. I guess that is exactly what lowering noise will get you? Very pleasing.

I, in addition, have eliminated sockets and plugs at the "end" of the power cord, retaining the IECs. This was done before the SIGNAL install and did make a difference. MUCH cheaper than the alternative (OYAIDE and the like). I have no interest in playing with various power cords, anyway.

Excuse my diversion,
Cordially,
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
rickmcinnis said:
by ZEN MOD!

If I knew 1/10 of what you know I would be (even more) dangerous.
Click to expand...

:rofl:

gimme a brake ; I know just enough to just barely know how little I know .
but - even most important thing to know is to know how to have a fun :cheers:


My speakers are high efficiency and the J2's duties begin at 75 hz.

The amp gets just above warm (my room is 57 degrees F.).

A very easy load, I would suspect.

Using TAD 4001's above 500 Hz and have never heard them sound ethereal before.
Click to expand...

even better - in that case - just try already mentioned big motor run caps as local bypass for cap bank ; one per positive and one per negative leg ; judging by pics of Papa's J2 , you have plenty of space to squeeze two of them .
my preferred brand is Icar Italy , but this is common brand on this side of big splash , dunno for your side .

another thing - if not for both ways ( TAD and lower driver ) than try this just on TAD - use dedicated cabling for them - using 0,25mm quality insulated solid core wire . independent routes for each polarity ( not twisted !!) and route them loosely .
thiner wire - better ; I use that type of cabling in last several years , but lately I read A.Wright's Supercable Cook Book , and accordingly tried even thiner wire than before . conclusion - AW knows his drek , very well .

for lower drivers you can try same wire , and if you feel lack of grunt - just double number of conductors - to 2 per leg .

Your suggestions for the supply are, of course, hard to argue with but one can also wonder if in my case one could add too much capacitance? I just might screw up my courage and do the BIG bypass, though. That makes good sense and would be relatively easy to do.

Just installed a SIGNAL DU-2 isolation transformer and was surprised how much better the sound became. I live in the suburbs and assumed my power was relatively clean. All of a sudden details, they were there before, but now they have a closely defined space. I guess that is exactly what lowering noise will get you? Very pleasing.
Click to expand...

that's trial game , certainly ; one of factors in your position is that amp is stock FW , and it will be certainly sort of blasphemy to butcher it and drill numerous additional holes ;

but you can always ask Papa politely to deliver exactly same power xformer , along with another exactly same cap bank ;
then you can mount new xformer on top of original one , additional graetzs need just few holes , and I think (!!??) that new cap bank you can squeeze on top of present one , with some extending screws , instead present ones .

hehe - many ifs ......

that way - you can squeeze last particles of details and clarity ...

I don't think that doubling xformer VA and PSU capacity is even remotely near "too much" area .
in any case - additional motor run bypasses are major contributing factor - at least to my ears , and having them - "too much caps" area is much further than in case of not having them .

I, in addition, have eliminated sockets and plugs at the "end" of the power cord, retaining the IECs. This was done before the SIGNAL install and did make a difference. MUCH cheaper than the alternative (OYAIDE and the like). I have no interest in playing with various power cords, anyway.

Excuse my diversion,
Cordially,
Click to expand...

even in that case - if amp is resident - try decent solid cores ; shielded (gnd-ed just on wall side ) , or not - only ears can decide ( considering that you don't have short circ. between them , as I have usually :rofl: )
 
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