The show of Boulder amplifier on thisdiy site,no meaning of to show,very expensive components they use and construktion very special crafted, no meaning for Diy, we can't build a Bugatti Veyron, stupid only or other miljon amplifier or other 100 000 amplifier's
I may be heading to Ontario CA later in the week for a few or more days
didn't know if any of y'all might be close or have a system set up
to have a listen to on of these bad boys.
I might need a break from Shopping etc.
didn't know if any of y'all might be close or have a system set up
to have a listen to on of these bad boys.
I might need a break from Shopping etc.
Hi Guys,
I changed my trimmers. I didn't have a 50k so I installed a 100k. Setting the VAS at 5.6mA had the trimmer down to 7K so I installed a 25k trimmer and changed R25 to 27K. Now I am reading about 40K from LED to LED.
I have the bias set to 68mA per device. It's been playing music for a couple hours now. Sounds lovely of course.
Here are my scope shots. Not as pretty as Thimios'.
Blessings, Terry
I changed my trimmers. I didn't have a 50k so I installed a 100k. Setting the VAS at 5.6mA had the trimmer down to 7K so I installed a 25k trimmer and changed R25 to 27K. Now I am reading about 40K from LED to LED.
I have the bias set to 68mA per device. It's been playing music for a couple hours now. Sounds lovely of course.
Here are my scope shots. Not as pretty as Thimios'.
Blessings, Terry
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I have good memory + insight.
The nicely rounded leading/ falling edge at 100k is the BEST I've seen.
That "rounded" = overcompensated. Nothing wrong with that , but
you could most likely drop C7/8 to 22p for another 1/2mhz unity gain
point ! (200Khz perfect SW).
This amp is textbook CFA , and "follows" the simulator results perfectly.
To get that perfect 5.3-5.5ma Ivas you could reduce R25 to 22k and trim
out R24 to spec.
Good work , Thimios ... you have a servo'ed "NX" on steroids that can
run a 250W OPS ! 😎
OS
But the best "full blown" amp picture 😱- you run the 250W ND !😎
You trimmed the LED I , I see. Bleeding off a couple more mA through
the LED's is not a bad thing. Led's are rated @ 20ma - 4-5 won't hurt.
Did you test the node between R4 and R7 ?? This is the servo
voltage , can tell you how close the diamond is matched by it's voltage.
OS
Hi OS,
I checked the node at R4 and I have 1.2V on the left channel and 2.3V on the other. To be honest, I went by what I though you said in post 6766. You said the super pair were the important ones to match and that because it was servoed Q1&2 could be mismatched. So I didn't bother trying to match them. I suppose I could replace them but this thing plays perfectly as is and the ofset is very low on both channels.
I've been listening for a few hours now and I really, really like it. After you mentioned the 250W I couldn't resist turning it up. MAN scary loud and strong. You should hear those 12" JBLs. Who needs a sub?
Blessings, Terry
I checked the node at R4 and I have 1.2V on the left channel and 2.3V on the other. To be honest, I went by what I though you said in post 6766. You said the super pair were the important ones to match and that because it was servoed Q1&2 could be mismatched. So I didn't bother trying to match them. I suppose I could replace them but this thing plays perfectly as is and the ofset is very low on both channels.
I've been listening for a few hours now and I really, really like it. After you mentioned the 250W I couldn't resist turning it up. MAN scary loud and strong. You should hear those 12" JBLs. Who needs a sub?
Blessings, Terry
Your alright ... 1.2 and 2.3 V would equate to about .1 - .2ma more current
for Q2 (that is your "weaker" semi -NPN).
Also , the super pair matching ensures stability and that perfect clip
on Thimios's scope .
My Kypton C's are both about 1V - I did DMM match them.
Glad these worked first time - I was careful in the design. 😎
Edit - really really like it ? This is what the "NX core" sounds like with NO loading
of the second stage. the super pair will never exceed picoamps - even on clipping !
You could overdrive this amp for a decade and never stress any IPS devices.
OS
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Mine clips perfectly too, I just didn't take a pic of it. This amp worked great right outof the gate. Someone should do gerbers for this one. I think this one would be popular. The first "super pair" IPS I used with the Slewmaster was the AX14 converted to and IPS. It played great right out of the gate too.
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Yes , the AX14 was one of my starting points. I combined it with a
Hawksford (Vzaichenko , as well). It did oscillate on the "kypton V" with
massive gain. Perfect on the C -lower gain CFA.
The hawksford/baxandall (super -pair) combo clips better , lower "early
effect" . Best of the VAS's , but can "interact" with the wrong design.
This is the "right design" for it (low gain CFA).
Member Waso's (Russia) CFA feedback scheme is also used in this one.
All the best ideas are here.
OS
Hi Carl,
I made a couple Word docs for doing iron transfer for bottom foil and top silk. Perfect for a 4" x 6" board. I'll attach it here.
I made a couple Word docs for doing iron transfer for bottom foil and top silk. Perfect for a 4" x 6" board. I'll attach it here.
Congrats Pete! Very cool compensation approach, BTW.
I also like the choice of transistors in the input diamond.
And of course - VAS arrangement, where "Mr.Hawksford meets Mr.Baxandall"
Lots of clever nuances in the right combination, man 😎🙂
You guys are bad.
Both you Terry and Thimios are teaching me
and the other DIYers here how to use scopes
as a tool to analyze amps.
Now you got me chomping at the bit.
I want to hear this puppy. The question is
how musical is it ?
What are your speaks and at what level are you
running the outputs?
AND
To what are you listening?
Now that is looking good.
How hard it is to make them boards Terry?
They are iron on...are they reverse etch?
What is the turn around time for getting boards made?
Anyone have another set or two of the others boards
to sell that aren't available any longer?
Both you Terry and Thimios are teaching me
and the other DIYers here how to use scopes
as a tool to analyze amps.
Now you got me chomping at the bit.
I want to hear this puppy. The question is
how musical is it ?
What are your speaks and at what level are you
running the outputs?
AND
To what are you listening?
Now that is looking good.
How hard it is to make them boards Terry?
They are iron on...are they reverse etch?
What is the turn around time for getting boards made?
Anyone have another set or two of the others boards
to sell that aren't available any longer?
Ok guys.....it's ALIVE.
Power supply=+-50v
VAS current=6.5mA I(R22)=1,5mA I(R25)=8mA Ivas=8-1,5=6,5mA
OUT. Bias=22mA
OUT devices=2sa1943,2sc5200 one pair
offset=0mV.
Excellent job here Θυμιο -still4given- ΟS with the first try.
OS if you want can you release the file .LAY extension Sprint 5.0?
Nikos
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Hi sinc,
Turn around from the people I buy from is about three weeks.That is mainly due to my using the cheapest shipping option. If you choose DHL you can cut the time to just over a week.
Etching boards took me a while to get right. Thimios uses photo etch boards which seem to produce beautiful results. I use the iron transfer method and am finally getting good results by using cheap shelving paper as a transfer agent. I also recently discovered using muratic acid mixed with hydrogen peroxide for the etchant. It takes literally 4 minutes to etch a board.
As to the sound of these amps? Wonderful! All of them. Nothing missing, strong bass, clear highs, open mids and huge soundstage. Everything I look for in an amp. OS did us a great service with this design and the other folks who joined in to either add IPS designs or do layouts have made this a wonderful ride. I believe at this point I have build them all. I just recently etched the Gnome and am still testing that one and I built the Krypton-C but not ironed that one out yet. I also built most of Valery's IPS and OPS boards that are based on this layout but 1/2 of those are tube hybrid.
If you are in So Cal frequently, PM me and maybe we can get together in the future and you can hear my amps. I am only about an hour drive from Ontario. I can't do it this week but maybe in the future.
Blessings, Terry
Turn around from the people I buy from is about three weeks.That is mainly due to my using the cheapest shipping option. If you choose DHL you can cut the time to just over a week.
Etching boards took me a while to get right. Thimios uses photo etch boards which seem to produce beautiful results. I use the iron transfer method and am finally getting good results by using cheap shelving paper as a transfer agent. I also recently discovered using muratic acid mixed with hydrogen peroxide for the etchant. It takes literally 4 minutes to etch a board.
As to the sound of these amps? Wonderful! All of them. Nothing missing, strong bass, clear highs, open mids and huge soundstage. Everything I look for in an amp. OS did us a great service with this design and the other folks who joined in to either add IPS designs or do layouts have made this a wonderful ride. I believe at this point I have build them all. I just recently etched the Gnome and am still testing that one and I built the Krypton-C but not ironed that one out yet. I also built most of Valery's IPS and OPS boards that are based on this layout but 1/2 of those are tube hybrid.
If you are in So Cal frequently, PM me and maybe we can get together in the future and you can hear my amps. I am only about an hour drive from Ontario. I can't do it this week but maybe in the future.
Blessings, Terry
Congrats Pete! Very cool compensation approach, BTW.
I also like the choice of transistors in the input diamond.
And of course - VAS arrangement, where "Mr.Hawksford meets Mr.Baxandall"
Lots of clever nuances in the right combination, man 😎🙂
Thanks , Val . 😎
Waso's CFA compensation has some hidden secrets. The two millers act
in a combined manner. 15pF + 15pF act like 33pf in the old design , stability
is the same .... but we are pushing 411V/us at this point. (below 1)
"Splitting" FB also lowers current and associated thermal distortion.
Even 1/2W FB resistors will run cool here.
We can push for quite the bandwidth and gain margin now ...
22pF to 33pF can be used safely. 2.5 - 3.2mhz UG crossover.
In the end , we have a amp that Doug Self will NOT include in his book
because it " has no use for audio" . 😀
PS - input diamond is actually 992/1845 pair , my 992 model is "screwy" ...
does not have a "k" or "c" after it ?? Anyone have a good 2sa992 model?
OS
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Hi Terry,
I've seen the etching materials at Fry's electronics and wondered about it.
There was a local place that made boards but I really never investigated
it, they might be having it done offshore too.
Chassis place needed 250 - 500 minimum.
Now I have an offer on TV I can buy silver for 21.95/1oz coins, plus
shipping handling. Thinking at $16/oz spot....
Then the guy is saying....if you buy 500 or more ounces, you need
to use a bank wire. Wondering how much that S&H is? LOL
PM to be sent.
Cheers,
I've seen the etching materials at Fry's electronics and wondered about it.
There was a local place that made boards but I really never investigated
it, they might be having it done offshore too.
Chassis place needed 250 - 500 minimum.
Now I have an offer on TV I can buy silver for 21.95/1oz coins, plus
shipping handling. Thinking at $16/oz spot....
Then the guy is saying....if you buy 500 or more ounces, you need
to use a bank wire. Wondering how much that S&H is? LOL
PM to be sent.
Cheers,
Sure (below). To go two layer , the ground star is the cause for most
of the jumpers. Run this on top (2 layer) and PCB will be jumper-less.
Diamond rail connections also make for jumpers.
Best to keep the "A and B" connections for the diamond. The twin red led
cascode co-efficient is opposed by the diamond co-efficient.
It should be close with either A/B , but A will increase the diamond.
If "B" turns out the closest , lower Vceo diamond pairs will be usable (>24V).
OS