Tube with Power IC Output Stage - JLTi

[Nielsio]

You are quite correct, I have read about a good
number of tweaks, but in making the JLTi I didn't
consider it another tweak but basically set out a
whole program development - a quite serious under-
taking, not to say time consuming. It lead to
some things I would not mind passing on to the
DIY fraternity.

This will be very much appreciated.

PS If I weren't a DIYer, I would most likely buy your amp; good price for a great product.

[Joe Rasmussen]

Originally posted by Nielsio


This will be very much appreciated.

PS If I weren't a DIYer, I would most likely buy your amp; good price for a great product.

I believe so, and the favourable reactions I've
so far are most promising. Thank you for your
kind remarks.

It's kinda funny that the JLTi ends up as a
subject in DIY discussion forum when it isn't
a DIY product.

It's only that it uses an element familiar
to some DIY-selfers. But so does other commercial
products as well. After all, audio is made up of
many diverse bits, DIY or otherwise. It's all about
how you combine them. It's cooking! :-)

But having said that, I would like pass on some
of my ideas (discoveries?) and let's see how it is
received. I want this contribution to be very well
thought out and presented. It may take about two
weeks as I may want to include actual measurements.
This will be a comprehensive presentation.

At least I have accomplished something others have
not done yet, combining tubes and the 'gainclone'
IC. The idea has been spoken about it, but has
anyone actually done it?

Personally I love the results - it works beautifully!

Thorsten sent me an email saying that he had
suggested it in a November post (another forum) and
gave me the link. But I had already started this well
before then.

Here is the URL he sent me:

Hybrid "SE Tube Amp Sound Style" Chip Amp idea

I didn't follow his suggestion of making the
'gainclone' behave more like an SET or adding 2nd
harmonic warmth. I trusted my instincts and went
for the cleanest possible signal path, the Tube
Buffer I use is very low distortion and very wide
bandwidth. Actually hugely wider than the IC, which
led to a problem I had to solve.

Another absolutely important aspect of the Tube Buffer
is the power supply solution I came up with. I also
the same idea for the optional Phono Stage, so have
a look, it the third illustration down on the page:

http://members.ozemail.com.au/~joeras/jlti_phono.htm

The main difference here is that the +15V/-15V is +55V/-55V
for the Tube stage.

Regards

Joe

[Serow]

Hi Joe, just wondering if you've had the time to get any work done on the schematic of your non-tube IC amp.

Regards,
Eric

[Joe Rasmussen]

Originally posted by Serow
Hi Joe, just wondering if you've had the time to get any work done on the schematic of your non-tube IC amp.

Regards,
Eric

Hi Eric

Please be patient. You will be happy to know that
I have already started preparing diagrams and
circuits.

There will two designs presented, one can be
easily adapted to current GCs, it requires a
number of values altered and a few additional
components. Also a change to either 10K Log Pot
OR 25 Log Pot. The original 50K Lin Pot will be
discarded.

The SECOND design will be far more ambitious. This
will be a simplified version of the JLTi. This is
for the SERIOUS constructor!

YES, A DIY HYBRID TUBE GC.

But the power supply solutions to the tube front-
end will need to be filled in by the DIY-selfer.
The +35V & -35V supply can be done using a small
25V-0-25V 30VA tx, toroidals should be available,
and same 1000uF/35V caps as using by the GC chip.
This will give us a very well filtered but unregu-
lated supply. If the constructor wants to regulate
this... go ahead with whatever solution you can or
want to come up with.

Also a 6.3V 330mA supply will be required for the
filament.

The choice of tube (suggestion) will be the same
as the JLTi, the Sovtek 'Relector' 6922, as this
tube will work at the low (no high-tension here)
voltages used.

Hope that has got your appetite up.

I'm looking at two weeks, hang in there.

Regards

Joe

[Joe Rasmussen]

Hi Guys

Check this out:



Yes, actual component values will be supplied.
This is the simplified JLTi for the DIY mafioso...

Promise!



Joe

[Nielsio]

#One mafioso getting excited

[Serow]

Originally posted by Joe Rasmussen

Please be patient. You will be happy to know that
I have already started preparing diagrams and
circuits.

[cut]

I'm looking at two weeks, hang in there.

Joe, take all the time you want. I realize that you're busy at your job, and DIY'ers make little or no money for you .

Thank you for the update.

[argo]

Seems I have missed this thread somehow. Yeah Joe, take your time and keep us posted.

[Nielsio]

Was just testing if my signature works, but I can't delete the message.

Well, guess I have to say something smart now.

Ok, I've got one:

Why is it that the exact grounding is never included in the schematics? Especially when it seems to matter so much.

Not everyone here is a Kuei, a Peter or a Joe.

[gpapag]

Originally posted by Nielsio
"Why is it that the exact grounding is never included in the schematics? Especially when it seems to matter so much."
=============================================
...Because, then everyone would be able to build a nice sounding equipment

Regards
George