Highest quality assembled board?

[dewardh]

View attachment 522479
My latest preamp.

Cute. All those parallel cathode followers should be able to drive your headphones (or "a $20.00 amp from China") just fine. Won't sound any better than a 5532, though . . . (and there are much better output devices now).

Your gadget reminds me a bit of the old Heathkit H1 analog computer technikum29 - Analog and hybrid computers (it had 45 12AX7s on top and more inside). Computers (even analog computers) have gotten better since then. They don't use tubes any more . . .

So have pre-amps . . . they don't either . . .

 

[brik]

Cute. All those parallel cathode followers should be able to drive your headphones (or "a $20.00 amp from China") just fine. Won't sound any better than a 5532, though . . . (and there are much better output devices now).

Your gadget reminds me a bit of the old Heathkit H1 analog computer technikum29 - Analog and hybrid computers (it had 45 12AX7s on top and more inside). Computers (even analog computers) have gotten better since then. They don't use tubes any more . . .

So have pre-amps . . . they don't either . . .

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I see this program is working out well for you.

 

[scholl]

But dewardh says you should just throw your preamp in the garbage if it cant drive an 3k3 input impedence,so if I try this I can keep my preamp?Man ,I hope so.
Either solution would be fine.
Be carefull,a logical post like yours is what derailed this thread.

Give it a try.

Another solution would be to direct couple a Dn2450 buffer stage from the anode of your current preamp similar to those little 12au7 headphone amps sold at Parts Express.

 

[brik]

Give it a try.

Another solution would be to direct couple a Dn2450 buffer stage from the anode of your current preamp similar to those little 12au7 headphone amps sold at Parts Express.

Scholl,This is my original post :

Just be aware those irs2092 boards have an input impedance of 3300 Ohms.Gonna be limited with what you can drive them with.
Those latest Icepower boards I linked to have an input impedance of 47k .Older Icepower boards were around 8k which is why many manufacturers who used them(P.S. Audio,Jeff Rowland,etc.) used input buffers or transformers to drive them.Driving the pair I have with a tube preamp with no issues at all.
Just figured I'd give you a heads up.

Then dewardh replied to my post with this:

I have on hand a couple LJM L15D single channel boards and a couple SURE dual channel (all IRS2092 "reference design" although the layout varies). Build quality is excellent, and there's nothing to be gained by "substituting" components on either.

As with all of the IRS "reference" amps their high end response is load sensitive . . . you need to pay some attention to how your speaker impedance behaves. It's easily compensated for (if needed) . . . and it's not an issue at all with "active" designs. The input impedance is also relatively low . . . but not so low as to pose a problem with any competently designed modern source, be it pre-amp or active crossover.

Even poorly designed (or antique) tube pre-amps (designed to drive equally antique tube amplifiers with high input impedance) are easily accommodated, since such contraptions typically deliver a higher output voltage than modern hardware needs, and will have to be padded down to be used with 2092 based (and in fact most modern) amps. The padding network usually raises the input impedance sufficiently that no "input buffer" is needed to make the old gear work properly.

He claims there's no need to use a buffer or transformer to increase the input impedance for an easier load for a tube preamp,just a padding network.I guess the designers at JEFF ROWLAND,B&O, BEL CANTO are all idiots.
I tried to explain to him that a padding network would destroy his source impedance and any ability to drive a 3.3kohm load, making things worse ,NOT better.It also wouldn't affect the 3k3resistor that sets the input impedance.
Then this mess of a thread appeared.
I don't even own an irs2092 amp.I have a pair of Icepower ASC300 amps.

 

[dewardh]

I don't even own an irs2092 amp.

Ah . . . no wonder you don't know what you're talking about . . .

 

[brik]

Ah . . . no wonder you don't know what you're talking about . . .

And now he stalks me.

So Ohm's Law and physics is different for each amp?????
Learn something new from you everyday.
Are you supposed to be using the internet?

 

[brik]

And now he stalks me.

So Ohm's Law and physics is different for each amp?????
Learn something new from you everyday.
Are you supposed to be using the internet?

"HEY DEWARDH,YOUR TURN FOR THE INTERNET"