Tranformer help needed

[M Fowler]

I am using the Turretboards.com rt 666 board and the schematic I have shows I need 370-0-370, 5V, 6.3 ct

The Hammond has the 274X and 290LX with these voltages. The 274X is not that expensive $69 but the 290 series are expensive. The JTM45 KT66 marshall replacement 50W seems to be the one I need but I do not want the laydown tranny. Any suggestions. GZ34, 2-KT66, 12AX7, EF86 tubes with cap can 40, 20, 20, 20.

The OT spec on the schematic is not shown but JTM45 is 8K for 50w kT66. Marshall replacement is 7,371 ohm CT 4, 8, 16 ohm Hammond 1750Q which seems to be a good choice.

Any and all help welcome, thanks.

Mark

[collinsamps]

The 290LX that I use is 300-0-300

Hammonds are fine transformers but I would go with Heyboer/Mojotone JTM45 PT(350-0-350) & OT. For standing up the JTM PT WEBER sells standup end bells that fit it. Mojo's are prewired and not solder tabs so they fit the endbells. Or while you are at Weber his W022798 or Heyboers(from him) is 360-0-360 and also fit the standup endbells. Both the weber or heyboer 22798 will get you 460 - 480vdc with that tube compliment and KT66's. I've been known to use a huge dropping resistor to get it down using them.

I'd like to see your schematic, mind sending me a copy to craig@collinsamps.com?

[M Fowler]

Craig PM sent

Mark


http://ampgarage.com/forum/viewtopic.ph ... =route+666

http://ampgarage.com/forum/viewtopic.ph ... 1&start=30 for zip file

[M Fowler]

I was looking at the Mojo trannies earlier tonight and they sure would work. Not sure that I need to reduce the 8k OT to 6.6k as some have suggested. With the KT66 tubes out on the market maybe I should consider lower voltage PT.

Mark

[collinsamps]

Webers has two secondary windings for playing with it. You can even mix one leg from the high & low windings with no issues for in between voltages.

Thanks for the schemo, I got curious and found the whole DRZ Zip file with the search function.

[M Fowler]

Craig,

I have no experience with the weber stuff but this forum and many other forums all state his transformers are china made and no good? I was just reading about them on metroforum tonight. The guys had bought the 6m45 kit and replaced almost everything due to being such cheap components that they finally realized they didn't save anything going with his kits.

Just what I read and I know, believe none of what you hear and half of what you see, CCR-Grapevine lyrics.

Mark

[collinsamps]

I concur about the kits, about 90% worthless parts, but have used his chassis' and iron with great results. Yes it's asian import stuff and I won't use it in a build for a customer, but I've used his 22798 and 40248 in some personal things that were damn good sounding designs. It's an option for saving some $ and getting the same voltage & current you want. At the end of the day a PT is a PT if it delivers the same specs. If you are building it for yourself and it's your wallet, it's an option.

[Normster]

You could try a Dynaco ST70 clone.

http://store.triodestore.com/mq060.html

360-0-360 @ 300ma, 55V bias tap, 5V @ 4A, and 6.3V @ 5A. Not exactly cheap at $128, but it's pretty close to the specs you're looking for.

[M Fowler]

Yes and gahult also sent me information on the Triode PA 135S as well.

Thanks guys every bit helps. I also did go back read the info I found under the search that helped.
I would think maybe I would better off settling for a little less voltage then the 370-0-370 called for especially with todays selection of KT66.

Mark

[M Fowler]

Root 666 build

Ok well with Craig Collins help I got the JTM 45 tranny set. I started on the chassis today and the drill got carried away and made unncessary holes in my chassis darn drill.

Oh by the way those Harbor Freight step drills work dam good even in steel for those that need some thing to make holes with besides punches. Not sure I will keep this steel chassis or start over on an aluminum and get the tube spacing better but at least I know what layout I want.

Mark

[M Fowler]

Well I decided to pulled the parts off once I had everything figured out to be where I wanted them. I then sanded the gray steel Hammond chassis which is drying right now. Then I will figure out my face plate either decals or hand painted? Then clear coat it. Never done this much detail before to a chassis another good reason to use a nice shiney aluminum chassis.

There is a discrepancy between the layout and the schematic regarding using a 25k bias pot or 50k bias pot. I plan to use the 25k like I did with my express combo amp. I am using a cap can 40/20/20/20. More picture will come as she goes together.

Mark

[gahult]

Mark,

Looking good.

I like the head cab.
What is it covered with?

Is it 3/4" wood? If so where did you get the metal corners from? I have looked (but nit hard enough) and don't seem to be able to find any appropriate for 3/4". Course I don't really know exactly what is so I may have passed them over.

Gary

[M Fowler]

Hey Gary, thanks, I have had some cabs sitting around for quite awhile.

That is a RT 66 head cab from Dr Z they sold me two of these from his blemished lot $100 each. I also have one EZG50 head cab to put a build in as well. I got a 212 open back blemished cab from Z for $175 as well.

But Mojo also makes Z cabs so if any one wanted a Z style cab you just tell them thats what you want. Not sure what mojo charges or if they offer those cab corners separately or not. They are 3/4 inch thick.

Gabkits has nice cabs but they are 1/2 or at least mine were.

Mark

[Sonny ReVerb]

...where did you get the metal corners from? I have looked (but nit hard enough) and don't seem to be able to find any appropriate for 3/4".

These are the ones I used a while back:

http://www.stewmac.com/shop/Accessories ... rners.html

[mcrracer]

BLT Sound is where I get mine

http://www.bltsound.com/index.php/categ ... et-corners