Just started the upgrade to 3 SE-100s

soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
Well,after 5 years of hiatus it's time to start working on the remaining three SE-100s.
Three pristine samples are going to be opened,their toroids will be sent for rewinding
for 230VAC, some beefing up on certain secondary windings (for KT90 use)and resin potting.
The boards are being dismantled away as we speak,and all parts will be thrown away,
(except audio transformers and chokes).
I have just received a big box from Farnell,a smaller from Mouser plus some from various ebay sellers.
All are various PS capacitors plus rectifiers that will be very handy when assembling them back.
I have decided on metal film resistors throughout the PS board and Kiwame carbon comp
2 watters for the audio board.Their promise for ultra low noise and "carbon sound" plus sensible
pricing proves very tempting.
Tube coupling caps will be SCR PPEs bypassed by SCR tin foils plus extra USSR teflon bypass for the amp that will be used for the tweeters.Usually i bypass with 1/10nth to 1/100th value caps.Will see...
Since i am going to use KT90's all around small modifications to the resistor values that control
the voltage to the tubes need to be made...
My initial fears about KT90 reliability have been amused by a five year use without any tube related incidents.Almost everybody is saying that the EH version is better constructed than Ei Jugo...
Till now i am using Ei as power tubes and EH as drivers but since i cannot find any Ei ones stocked my third amp is going to be al EH ...
I will post pictures of the ongoing process...
 
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soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
I have received emails from pcx and hificollective that my Kiwame are on their way...
Last Friday i received from Farnell some heavy duty rectifiers from IXYS (specified at 1800V,20W)
that were on order.When the Kiwame is here,i will only need the rewiring of the toroid transformers
to be ready for assembly...Anyone has spare EI KT90?
 

soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
I know it is a hard fact that Ei stopped production after the NATO bombings.
If GE as they say has taken the plant maybe they plan to start production again...
Anyway EH KT90s are abundant and i'll have no problem with retubing...
It just pisses me off that i'll have to stick to one flavour!
 

soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
Update on the proceedings: A PS board and an Audio board are done.The sure look pretty!
I am working slowly, as business is brisk this time of year and my spare time is non existent!
I owe you some pictures...soon!
 

soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
Fewww!I 've found the time to take some photos of the finished boards.I am waiting for the transformers to arrive (from 115VAC to 230VAC + some beefing up on certain voltage taps+potting).
All ingredients are first rate.Everything has been exchanged to higher/st spec.All that is left is to change some wires.I can't wait to hear the finished product.
See some pictures of the tube board:
 

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soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
And here are some photos of the PS board:
 

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JackD201

WBF Founding Member
Apr 20, 2010
12,304
1,420
1,820
Manila, Philippines
Any way we can shrink those pics?

SoV, are you doing the assembly yourself?
 

soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
Yes i am.
Right now i am waiting for some special pieces from the CNC shop.
These include aluminum plate for the top,a cosmetic aluminum piece on front,
a cage to protect the tubes from kids hands (and kids hands from tubes) and finally
six solid bronze feet with a cutout for elastic insert.
I am a vet and summer is a bit hectic (full steam ahead season), so i had to let go of
my plans for a while.
Now i am back on track!
I will post pics of any new items as they arrive...
 

soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
Still waiting for the CNC to deliver...
In the meantime i have taken a couple photos from the storage place where three SE-100s are waiting for their transformation.
My friend has pulled back from the cosmetic work (have you heard anything about the financial situation in Greece?)
and so i am expecting the pieces for just one (the third of my SE-100s).
This one is going to be modified as the other two for operating with Ei KT-90s, and my friends' are going to get upgraded too
but he is keeping the EL-34s.
Also included is a photo of the scarse SEP-3 top of the line preamp (complete with the internal
tubed board for phono).
Also a pile of components waiting to find their way into the amps...
 

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soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
Finally the pieces are starting to gather.
First are the aluminum pieces from the CNC.
The bigger piece is a decorative plate on top of the amp where the tubes are located.
This will be screwed on place (from the underside) and a sheet of Dynamat will be sandwiched
between the existing steel cover and this plate to further suppress vibrations on the cover.
The thickness is 8mm.
It's front is bevelled at 45 deggrees.
There are 11 round holes cut into it for the SE-100s arsenal of tubes...
Second is a small piece of aluminum,about 12 mm thick that goes underneath the golden fascia of the amp
and "masks" the ventilation tunnel opening.
Reason for it?
I like the looks better...and that is all!
Third is a small plaque describing the type and wattage of the amp.
This will be on the cage that protects the tubes.
Again cut from solid 6 mm thick piece and engraved from the same CNC machine.
Since this amp will be used as stereo, it's plaque will be different from the ones used in the monoblocks.
See the photos...
 

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soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
?ext came the new feet ,cut from solid bronze with cutouts for a industrial rubber inserts.
Each foot is screwed under the chassis on the original position and then the rubber insert
is glued on place.The rubber has a hole so that i can reach the screw and take of the foot if i want to.
I made six of them as i use two extra ones placed under very heavy portions of the amp
(under the toroid on one side and between the two output transformers on the other side)
See pictures of them before they are polished and clearcoated...
 

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soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
And third is the tubes' protective cage (something this amp was never produced with).
I have two kids, 14 and 8 who are rather active in my living room and although i don't expect them
to touch the tubes when hot, i do expect some cuddly toy or soft ball/pillow to land on them from time to time...
And since Ei KT90s are now equally scarse as the Dodo,i have to take precautions for their well being.
Lucky for me i have managed to gather enough Ei KT90s for a complete retubing of all three amps (when this is needed)
but that is no reason to be careless...
Now, regarding the cage: it is made from 1,5 mm inox sheet steel press cut and expertly welded from inside and then
powder coated black (as the amp).
I have drilled holes into it's corners where small plastic caps are inserted and secured.
These cups are essential if you want the cage to be secure on place and in the same time being easy to take off as i never
listen to music with the cages in place to reduce the heat soak on the amps.
Also on another photo are the WBT/ Neutrik bits and pieces that are going to replace the original ones...
 

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soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
Also came four custom CNC cut screws. These are going to replace four of the screws tightening the amp's top.
Their elongated heads will fit in the four plastic cups that will be glued in the tubes' cage.
They also secure in place the custom aluminum plate decorating the amps' top.
They make a very tight and secure fit and is the best solution that i could think regarding the cage.
See some pictures that explain the whole thing...and show the final outcome.
I think it's very neat.
 

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soundofvoid

WBF Founding Member
Apr 22, 2010
173
11
365
Athens/Greece
Photo0300-Optimized.jpg Photo0299-Optimized.jpg Three freshly winded power toroids have arrived.
As the amps were bought from USA/Canada the toroids were for 110V input AC power.
In Europe it's 230V and they had to be rewired...
In doing this i have also asked for a bit more juice for certain voltages as i am going to use KT90s
instead of EL34s.
I have also asked for a potting on the inside plus a special earthing winding...
Here are a couple photos...
 

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