Liverpool PI

[ckpop]

Hey everyone on the original schematic of the liverpool was the original values 100k/100k/100pf or posted is that the perferred values of 100k/82k/47pf.
I want to start original and make changes from there



Thanks

[jaysg]

Hey everyone on the original schematic of the liverpool was the original values 100k/100k/100pf or posted is that the perferred values of 100k/82k/47pf.

If you have some NOS Mullards, you can go with 100k/100k...otherwise, use the 82K. The cap value doesn't really matter between the two.

[Cliff Schecht]

What is the purpose of that cap?

[Structo]

I don't know the whole technical or math part of what it does but in practical terms, it is to cut some of the high frequency fizz that sometimes occurs with a long tail pair phase inverter.

[dartanion]

The difference between using 2 100K vs. 100K & 82K is whether you want a balanced PI or not.

[ckpop]

I started with the 100k/100k/100pf and will listen before I go to the 100k/82k/47pf so I have a reference for both.

I'll spend about a week of listening and tuning with different NOS preamp tubes and other tricks to get the amp dialed in.

The Liverpool is definitely a harder amp to build in the output section. It takes time getting all the wires just right in the lead dress.

Almost done, have a original dynaco A470, can't wait to finish

[hairyandy]

I started with the 100k/100k/100pf and will listen before I go to the 100k/82k/47pf so I have a reference for both.

I'll spend about a week of listening and tuning with different NOS preamp tubes and other tricks to get the amp dialed in.

The Liverpool is definitely a harder amp to build in the output section. It takes time getting all the wires just right in the lead dress.

Almost done, have a original dynaco A470, can't wait to finish

I don't know if you necessarily want an A470 for a Liverpool OT, if you want to be "correct" anyway. I believe the Dynacos are 4K while the Liverpool OTs were 5.2K or sometimes even 6.6K like an Express? The A470s are better suited for the Rocket. Having said that, wire it up and see what it sounds like and let us know!



Andy

[ckpop]

Yes the dynaco A470 is 4.3k but just curious how the liverpool design and the dynaco work together or not. Let you know when I am done.
Almost there[/img]