Ironamp Video Posted

[DIYspaceW]

Temptation to build a SIT ironamp is high.

However, apart from the semiconductors it is an entirely new amp compared to one of the known L'amp versions and it requires major investment. Do we really need to go the whole nine yards to experience SIT with transformer output*?

After rereading the articles in «*L*'Audiophile*»concerning the NEMESIS amplifier, i came across the «*Compensated Nemesis*». Also rereading the blog from 2005 «*DC compensated SE output transformer*» i thought i would share what i came across, since not all of you may be fluent in French.

The result is that we may be able to do an ironamp without buying a SE output transformer.
Those who allready have a L'amp version could use their power supplies.
Those who have built the inductor version of the L'amp might be able to put their chokes to good use.
Those who have spare heat sinks can do a CCS version.

In «*L'Audiophile*» Pierre Johannet presented the «*Compensated Nemesis*». It uses a gapless output transformer (actually a mains transformer) with flux compensation (CCS version). (translation of the article attached)

In the blog «*DC compensated SE output transformers*» entry #122, plovati posted a proposal for a version with a choke. (cf. Attachment)

I prefer the inductor version over the CCS but care must be taken to guarantee more or less equal currents in the windings...

Best regards

In my opinion its just a journey into one of it...All versions have their own ad-and dis advantages. The simpliest is still the L simple SIT from Michael.
I tried only two of them. But what looks like is that the SIT is a very neutral device. In both versions I tried the sound differences are made by driver and pre amp! So I would not bother so much whit iron. I made it whit iron and the sound is a little bit on darker side, but this is what I like, so its all about taste and color...At the end I must say, 2sk82 is a great transistor! Why the f--- does no one more bother to produce something similar,
it would make more ideal world of music reproduction in my opinion!

 

[jostwid]

Compensated Ironamp

In my opinion its just a journey into one of it...All versions have their own ad-and dis advantages. The simpliest is still the L simple SIT from Michael.
I tried only two of them. But what looks like is that the SIT is a very neutral device. In both versions I tried the sound differences are made by driver and pre amp! So I would not bother so much whit iron. I made it whit iron and the sound is a little bit on darker side, but this is what I like, so its all about taste and color...At the end I must say, 2sk82 is a great transistor! Why the f--- does no one more bother to produce something similar,
it would make more ideal world of music reproduction in my opinion!

Many thanks for the reply! One day somebody will come up with another interesting semiconductor (hope dies last...)
The primary goal of my previous posting was to make others aware that they might be able to experience an ironamp without having to make any investment in further hardware. All you need is a monoblock of the inductor version of L'amp + the power supply transformer from your second monoblock converted to OT use.

In addition, the articles in L'Audiophile are highly interesting. Those people had done a great job. Particularly i am interested in the ones concerning thermal distortion. Does anybody know about an english version?
Best regards

 

[flg]

IIRC A guy named Cheever did a thesis on the subject and it is available on the www

 

[v_]

Fancy input transformers

Nice work there G! A 3-4V range for the N's would agree with what I've seen so far.


I have some fancier ones from Lundahl and Sowter, but I haven't listened to them yet. For the published project I wanted to keep it all Edcor, and leave the tweaking fun to the experts.

Hi Mike,
Have you tried those transformers? What part numbers do you use?

Thanks,
Vlad

 

[JZatopa]

Great video

 

[Michael Rothacher]

Thank you. Much appreciated. I'm still waiting on a few parts for the power supply. Nothing fancy. It will be a straight-forward unregulated arrangement, and those who want regulators and such can make those changes to suit their own requirements.

 

[Michael Rothacher]

Hi Mike,
Have you tried those transformers? What part numbers do you use?

Thanks,
Vlad

I have a few transformers on hand for other projects such as Sowter 8920, Lundahl LL1690, and Jensen JT-11P, but I haven't tried them in this project.

 

[Soundhappy]

In early transistors days we have see interstage transformer coupling
solid state amplifier in commercial phonograph from Philco
that is fun to read page with topology explanations from year 1955.

Iron was commonly used and little count of components
i like it ...and though updated to "modern" era can give purer sound.

For better vue please zoom on

Best regards

 

[Soundhappy]

Ok Philco is push-pull one
Was just inspire me to think how much complicated be make
parallel single-ended Ironamp with twice of power ?
Hmm...for house dance party
Impedance adaptation scenarios ?

Have a nice day

 

[Michael Rothacher]

I tested the power supply over the weekend and everything looks pretty good. Should be on track to make the final build video in mid-late March.

 

[Soundhappy]

I tested the power supply over the weekend and everything looks pretty good. Should be on track to make the final build video in mid-late March.

Excellent

Can be too early to have data for PSU transformer ?
What choice the good ones ?
Thanks You for news Mr Rothacher

Best regards

 

[Soundhappy]

Yes, it's certainly an homage to the WE25B. Though I'd love to have some some more info on that one, if anyone would like to share.

Interesting Originals Service Manuals for solid state adaptations of tube amplifiers with schematics,BOM, photos etc...by Western Electric with transformer coupled, lot have ultra minimal signal path and be dedicated to play with high efficiency horns or speakers et voilà

Western Electric

 

[Zen Mod]

Shappy

will you recommend me that sort of weed , you're wasting ?

 

[Soundhappy]

Shappy

will you recommend me that sort of weed , you're wasting ?

Bonjour@Zen Mod

I don't but You have recommended me maybe something ???




Sorry but if is not connected with transistors like Sit's Vfet's triode valves amplification and transformers coupled or other always Ironamp...i don't wasted Your dodo time.
Any help is Sissi apreciated and she like ZEN MOD

 

[Zen Mod]

 

[Soundhappy]

Greetings ZM

 

[Soundhappy]

Should be on track to make the final build video in mid-late March.

Hi Mike
Acronman 2SK82 KD-33 grade is out off stock now i imagine this is reason for adaptation of Ironamp for KE-33.
Personally i have KD grade on my table and think others diyers to.
Could we have two versions KD and KE in your Ironamp video part II ?
Thanks for response
Best regards
Christophe

 

[Zen Mod]

just matter of bias voltage

if , when starting with max. negative bias voltage , you have greater Iq then anticipated/planned - you need few volts more

so - simple - make it right now like that

 

[DIYspaceW]

For all new here, you dont need to buy 4pairs of 2sk82! They are very very reliable,
will last decades (just assuming), whit proper handling for shure!
Mine are in use a little less then one year and work stable!
My 2 cents...

Dont drain the river out of its time...

 

[Michael Rothacher]

Yes, what ZM says.

Also, here's a little update: I just got my top panels and custom parts from Edcor. So, I'm working on the final assembly as we speak. Then to make a video, which takes time.