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Jens Rasmussen Leach clone group buy

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JensRasmussen

JensRasmussen

Member
Joined 2002
Re: output terminals are moved

tryonziess said:
Jens, While you are asking for suggestions I was thinking that the resistor solder holes could be just a little bit larger. Some of the Vishay/Dale resistors have quite large leads and are TIGHT. This is probably too much trouble, but a suggestion.
When you had your original boards made which company did you choose to produce the boards? Tad
Click to expand...

Tad,

I all depends on the PCB company.... some think that the tool list contains their pick list for tools, others expect that it is the final hole size. I specify the final size, so it is up to the PCB manufacturer to scale the tools to match their plating process.


Bob,
I made the holes for the emitter resistors bigger, final size should now be 1.1 mm

loek said:
What about the coil and R57/C34 ?
Loek
Click to expand...

Loek,

These will be moved also.

\\\Jens
 
A

AndrewT

R.I.P.
Joined 2004
Hi,
this is based on the Leach Low Tim design but with some component value changes to suit a 5pair output stage (To247/To264).
The missing IV protection resistor is re-instated. All the components are from current production, rather than the obsolete devices in the original 70s articles/papers.
 
P

pooge

Member
Joined 2003
One of my biggest beefs with the original board is the space provided for the feedback electrolytic. Whether or not one regards different types of components as audible, one cannot even try to substitute for different ones here to find out, as there is no room for electrolytics of "audiophile" quality, or ones of higher value, or wider pin spacing. Leach provides a variety of pin spacings to accommodate different sizes, and is one of the things I'm trying to provide in my own board design, among other things set forth in a previous thread.
 
BobEllis

BobEllis

Member
Joined 2003
Shaun said:
Thanks, AndrewT.

How do the names Superamp and Double-barreled fit in here? Earlier in the thread there was also mention of at least three variations: High power for high impedance loads, High power high current and one lower power (IIRC).

And this one is...?
Click to expand...

This is not a Leach Super Amp A.K.A. Leach Double Barrel Amp. Jens is/was working on an update to that amp, as discussed in another thread.

All of the versions in this thread are variants of the original Leach Amp A.K.A Low TIM Amp. Jens has graciously given us two versions of the Leach Low TIM amp.

The first was a 6 output device (3 pair) version that closely approximates the capabilities of the original Leach - Suitable for 8 ohm use or lighter duty 4 ohm use at a range of rail voltages from roughtly 45V to 60V.

The second version, which is the topic of another possible group buy, is a ten output transistor version. This is the design of choice if you want to bump the rails up to 80V or so (200+W) or need to drive low impedance loads at high power levels with standard (~55V) rails.

Either version scales to different rail voltages with very little effort. Jens also provided the capability to power the front end from a separate (regulated) supply. This is supposed to fairly dramatically improve performance, but I haven't got around to trying it yet.

Hope that this helps.
 
JensRasmussen

JensRasmussen

Member
Joined 2002
pooge said:
One of my biggest beefs with the original board is the space provided for the feedback electrolytic. Whether or not one regards different types of components as audible, one cannot even try to substitute for different ones here to find out, as there is no room for electrolytics of "audiophile" quality, or ones of higher value, or wider pin spacing. Leach provides a variety of pin spacings to accommodate different sizes, and is one of the things I'm trying to provide in my own board design, among other things set forth in a previous thread.
Click to expand...


Hi,

Do you have a specific type in mind?

I fear that it will be a big job implementing a bigger type capacitor on this layout.

All others, did you have time to look at the latest PDFs??

\\\Jens
 
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