Ikezilla Pics - the 150W Monster

a DIY, modified Mullard 5-20 monoblock design

Ikezilla Pics - the 150W Monster

Postby Shannon Parks » Wed Nov 23, 2005 8:06 pm

Remember folks, this is Thermion's 'proof of concept' prototype. He's already got the Zebrawood ready for the real ones.

Chassis:
This was an old Knight integrated EL84 amp. The one given to me which started it all! It is darn stout and hardly shimmies at all with all the weight and the 'open construction'.

Iron:
PT is the Toroid of Maryland branded 'transformer for tube amps'. Barely gets warm. Output is a Hammond 1650T (120W, 1900 ohms).

Tubes:
Looks like a freebie Toshiba 12AX7 (from a nice old gent at the last Peoria Superfest), JAN 6SN7GTB, and a quad of pretty-well-matched, >3000 hour Sovtek KT88s. Hey, you don't think Thermion was going to blow up his best tubes, did you? Yellow_Light_Colorz_PDT_02 But seriously, you've gotta give props to Sovtek for this fine tube.

Load:
Kludged 4 ohms for 200W or so (forget).

Circuit:
We used 39 ohm, 5W resistors for the 'plate stoppers' and 100 ohm 3W ones for the screens. Just kinda what we had on hand.

Image
Image
Image
Image
Image
Image
Image
User avatar
Shannon Parks
Site Admin
 
Posts: 3764
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Postby WA4SWJ » Fri Nov 25, 2005 1:46 pm

A-W-E-S-O-M-E guys!

Schematics next? (I know, we're never satisfied!)

Regards,
Ed Long
User avatar
WA4SWJ
KT88
 
Posts: 650
Joined: Mon Dec 27, 2004 8:39 pm
Location: Belleview, FL

Postby erichayes » Sat Nov 26, 2005 7:58 pm

Hi All,

Just a comment on the screen and plate resistors: since these are more for current equalization than for parasitic suppression, fairly low resistance values (such as those you've chosen) are desirable--generally 22~150Ω. I arbitrarily chose 47Ω because it seemed like a nice median. The wattage shouldn't be more than 2W, as these resistors also serve as fuses for protecting the OT when (not if) the 6550s shift into Roman Candle mode.

BTW, are you using separate control grid stoppers on each output tube? That helps the parasitic problem quite a bit.
Eric in the Jefferson State
erichayes
KT88
 
Posts: 987
Joined: Fri Jan 23, 2004 9:01 pm
Location: McKinleyville CA

ikezilla

Postby audioray » Sun Nov 27, 2005 8:20 am

hello shannon.
will you have documentation ALA Mapletree that shows point to point wire
connections and BOM.
i still have a lot of hum from org. build. maybe something new will help.
thank you
audioray
 
Posts: 57
Joined: Wed Mar 19, 2003 4:04 pm
Location: Boston MA.

schematics

Postby Shannon Parks » Sun Nov 27, 2005 12:31 pm

WA4SWJ wrote:A-W-E-S-O-M-E guys!

Schematics next? (I know, we're never satisfied!)

Regards,


Hi Ed,

You bet - sometime by Christmas (if you've been good). Yellow_Light_Colorz_PDT_10

Shannon
User avatar
Shannon Parks
Site Admin
 
Posts: 3764
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Re: ikezilla

Postby Shannon Parks » Sun Nov 27, 2005 12:33 pm

audioray wrote:hello shannon.
will you have documentation ALA Mapletree that shows point to point wire
connections and BOM.
i still have a lot of hum from org. build. maybe something new will help.
thank you


Hi Audioray!

Are your boards Rev A or B? Could you please email me a couple up close photos of the interior? Also, I have a list of Eiclone 'tweaks' that I've compiled and those will be posted when I get back from vacation. We'll get it de-hummed.

Shannon
User avatar
Shannon Parks
Site Admin
 
Posts: 3764
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Postby Shannon Parks » Sun Nov 27, 2005 12:37 pm

erichayes wrote:BTW, are you using separate control grid stoppers on each output tube? That helps the parasitic problem quite a bit.


Hi Eric,

Yes, Thermion used the 'Dyna Method' of mounting the grid stoppers at pins 5 & 6.

Thanks for the other stoppers tip. We weren't sure what values were optimum. Without them (but with the grid stoppers - 1k?), we had blue arcing. Yellow_Light_Colorz_PDT_10

Shannon
User avatar
Shannon Parks
Site Admin
 
Posts: 3764
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Postby TerrySmith » Sun Dec 18, 2005 10:58 am

Possibly fit on a MK-3 chassis? Ditch the 5AR4 for one KT88, punch the quad cap hole for the other KT88. Use half of the ST-70 driver board or the MK-3 board that may be on the way.

Will the Hammond output fit on the chassis?

Is there a can available for the BUTT UGLY Yellow_Light_Colorz_PDT_07 Toroid transformer?
T. Smith
User avatar
TerrySmith
KT88
 
Posts: 973
Joined: Sat Jan 31, 2004 12:51 pm
Location: Maryville TN

Postby EWBrown » Mon Dec 19, 2005 7:05 am

Might be like trying to stuff ten pounds of er, rocks, into a five pound bag... The MKIII chassis is already a tight fit with two less tubes, it is really shallow inside, just enough room for the C354 choke to clear... .

Use SS rect, which frees up one tube socket, and use the can-cap location for the fourth one, then there's the issue of stuffing the Ike board (even if the "output"section is trimmed off) inside (or on top)... Maybe a trimed ST70 "brown board". The original MKIII iron is pretty large, check the Triode site for the dimensions of their replacement iron, and compare to the Hammond OPT. Dunno about the toroid, that may take some meghanical ingenuity.

One thing about the original Dynaco, they didn't believe in "wasting" any space on top of, or inside their amp chassis...

/ed B in NH
Real Radios Glow in the Dark
User avatar
EWBrown
Insulator & Iron Magnate
 
Posts: 6389
Joined: Wed Mar 19, 2003 6:03 am
Location: Now located in Clay County, NC !

10 lbs of rocks

Postby Shannon Parks » Mon Dec 19, 2005 7:26 am

EWBrown wrote:Might be like trying to stuff ten pounds of er, rocks, into a five pound bag...


Ed's got this one right. I mean, it <could> be done, but it would be a mess.

I do hope to try out Front Panel Express this year. We could have generic stock panels punched up for any projects. I plan to order a top plate for a SET this coming year, but Thermion had to slow me down with high wattage aspirations first.

So yes, I do plan to have a Mark II/III/IV board available soon so that part of it would fit. Spent all weekend on it (blasted cold is only good for 'toob work') and am very pleased with the results. More info shortly.

Shannon
User avatar
Shannon Parks
Site Admin
 
Posts: 3764
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Postby EWBrown » Mon Dec 19, 2005 10:06 am

Friday's ice storm in NH was definitely good for toob work, I got my BH 300B "Paramount" monoblox playing! No smoke, no flames, no funny smells, just nice 8WPC music. Those russkie 300Bs can also double as plasma globes, At least in a dark room. Free light show included... Yellow_Light_Colorz_PDT_01

Those old original Dynaco ST70s and MK series amps made nice winter room heaters, as they ran everything pretty close to the limit, and crammed everything into as little space as was possible.
The new Triode iron does run cooler, as they have less internal resistance and better insulation inside. And none of those old nasty tar-dipped PA774s... Yellow_Light_Colorz_PDT_38

/ed B in NH
Real Radios Glow in the Dark
User avatar
EWBrown
Insulator & Iron Magnate
 
Posts: 6389
Joined: Wed Mar 19, 2003 6:03 am
Location: Now located in Clay County, NC !

6V6?

Postby dhuebert » Mon Dec 19, 2005 1:33 pm

I have an old GE 6V6 that I peeled the glass off of, I notice the plate is connected to both pins 3 and 6, What would happen if I plugged it into ampzilla? (It came out of a Garnet Mini Bass with 450V B+, 30 year old amp, original tubes)

BTW what is B+ on ampzilla?

Don
User avatar
dhuebert
KT88
 
Posts: 820
Joined: Thu May 01, 2003 9:26 am
Location: Winnipeg Manitoba Canada

Re: 6V6?

Postby Shannon Parks » Tue Dec 20, 2005 6:49 am

dhuebert wrote:I have an old GE 6V6 that I peeled the glass off of, I notice the plate is connected to both pins 3 and 6, What would happen if I plugged it into ampzilla? (It came out of a Garnet Mini Bass with 450V B+, 30 year old amp, original tubes)

BTW what is B+ on ampzilla?

Don


Hi Don,

Were a lot of 6V6s connected like this I wonder? Seems odd to have plate voltage connected to a N/C. In the Ikezilla config, we are using pin 6 as a tie in for the grid stopper.

The B+ of the Ikezilla was in the 450-500V range. I say 'range' because Thermion has 127VAC mains AC where he lives, and he is tweaking them with that in mind. So I've been inching up the Variac to simulate that.

Shannon
User avatar
Shannon Parks
Site Admin
 
Posts: 3764
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Postby TomMcNally » Tue Dec 20, 2005 9:18 am

The strangest 6V6 I ever encountered was the crappy "International" brand. I had a pair of them (metal) in a Gate Sta-Level compressor, when they died, I peeled the metal off to use the base for something, and found 6AQ5's in seven pin sockets inside ! You can find a whole page of re-numbered tubes and the like in "the hall of shame" on

http://www.vacuumtubesinc.com

Maybe that 6V6 was a fake ?
User avatar
TomMcNally
Darling du Jour
 
Posts: 2729
Joined: Sat Nov 19, 2005 2:19 pm
Location: Northfield, NJ

International tubes

Postby EWBrown » Tue Dec 20, 2005 9:29 am

Those "Internationals" could be anything from re-branded pulls and rejects, to new Telefunkens and Mullards. The "Lifetime" tubes from Rat SHack years ago were the same league, from gold to garbage, just depends on the luck of the draw.

The enormous "plinker pile" of over 20,000 tubes that I rescued last spring, were from United Electronics, who was (in)famous for such rebranding activities, these were tubes waiting to be checked, washed off and re-branded and re-boxed. About 90% of them were true "plinker" TV tubes, and the remaining 10% had some real gems and very useful tubes. I kept the good stuff and passed on the remaining plinkers to a friend who has a large storage building and a huge old tube collection, so they have a good home for the foreseeable future.

I guess the "Lifetime" really meant it, recently a friend of mine brought back four dead "Lifetime" 7951s to his local radio shack, and they eventually replaced them for free (the tubes came from AES). He also said that he never saw four such mis-matched tubes all in one batch before.

So, don't throw away those Lifetime tubes - or old craftsman tools.

/ed B in NH
Real Radios Glow in the Dark
User avatar
EWBrown
Insulator & Iron Magnate
 
Posts: 6389
Joined: Wed Mar 19, 2003 6:03 am
Location: Now located in Clay County, NC !


Return to eiclone

Who is online

Users browsing this forum: No registered users and 9 guests