Info on a Heyboer OT

[piperbob]

I have a Heyboer OT that I plan to use for my second Expression. The primary side has 5 wires coming out. I've tried to look for info on the web for a multi-tap Heyboer but haven't hit pay dirt yet. Facts about the transformer:

label on top "11415-1 9960746"
red wire
brown wire
blue wire
brown wire w/white stripe
blue wire w/ white stripe

I think this OT can be used for 5.2K & 6.6K service but the primaries baffle me. Anyone have any ideas? I emailed Heyboer but don't know how responsive they are so I thought I'd try asking here too. Any help appreciated.

[rooster]

What you have there is a 'tapped' primary OT. The striped wires are the screen grid taps for the similar yet solid colored wires. Take your DOM and measure the resistance from center tap (red) to the extended coil wires, brown and blue, etc.. You will find a connection to the like colored wires.

Um, you do not have to use the taps, BTW, which will make this a 'normal' OT. Just tape or heatshrink them off, secure them somewhere.

[piperbob]

Thanks rooster!

[RJ Guitars]

Piperbob,

See if these colors match up to what you have and confirm the info that Rooster gave you...

rj

6.6K Ohm - Blue / Brown
5.2K Ohm - Blue-white / brown-white
Red = Center tap

16 Ohm - Gray
8 Ohm - Yellow
4 Ohm - Red
Common - Black

[JamesHealey]

That is the earlier dual primary OT which has 5k2 and 6k6 taps.

[piperbob]

Thanks for the input guys. RJ, the OT has those exact colored wires. I bought this knowing it had two different output impedences but was not sure which was which. Out of curiosity is there a way of measuring the wiring with a DVM in order to figure out the impedance? I plan to use 6V6's with this build just to have something different than my Express with el34's. I have Sozo premiums that I plan to use too. Any advantage to using the 5.2K taps?. I would like to have as creamy and compressed sound as possible. Loudness isn't my goal with this amp. More of a tone monster. I have gotten hip to VVR's too and plan to put one in in the near future. I have one in my Express and Liverpool and really like them.

[RJ Guitars]

Piperbob,

This is the unit that Toneslut sold for a long time. Eventually the single impedance trannies became more popular... I think they are closer to the original Trainwreck specifications. Having said that, there are a ton of clones out there using this transformer and many of them are killer units... definitely a good output tranny for a Wreck.

6.6K is a decent matchup for a set of 6V6's although the reports always seem to favor the EL-34's in the Express. A few 6v6 amps have been declared as great tone machines but the nod usually goes to the EL-34's.

These is little harm in trying the 5.2K tap as far as the technical matchup of things is concerned. It should sound different and your ears can be the judge as to whether it's better or not.

I have a 5 page document on how to determine the impedance of an output transformer. It doesn't really take 5 pages to explain how to do it but it's got a lot of other interesting stuff too. Way more than I can cut and paste here... send me an email to: info at rjguitars dot net -- I can send you that tech note as an attachment if you want to read over it.

rj

[rooster]

Arrg... Oh yeah, that OT! I was thinking it was just a screen tapped OT and not a dual primary OT. Sorry for the confusion, RJ has told you correctly.

[piperbob]

Thanks RJ & rooster!

[M Fowler]

Here is tonesluts schematics.

[JamesHealey]

I've used this ot twice before and it sounds great bit more aggressive in the mid than a pacific but a great tone for sure!

[piperbob]

Thanks for the info guys. I have a three day weekend starting today and assembling this amp will be my project. Got to go to the hardware store now for some nuts and bolts then a blood test. I have a metal mitral valve and get tested now and then for my coagulation levels. Anybody have non factory standard parts on themselves? Implants etc?

[M Fowler]

Have fun with that amp project and take good care of yourself

[piperbob]

M Fowler, thanks. I had open heart surgery 4 years ago to my mitral valve due to a congenital condition. Can I sue my parents for manufacturing a defective product ? I got the treadmill and ultra sound tests done on my heart last week and things turned out great. I'm in real good shape for being 55. Went to the dentist this week and found out I need a crown on a molar and deep cleaning of the gum line. God dammit getting old sucks! When I start talking to others at work about health problems I find out I am a total light weight and don't have anything to complain about when I hear of other folks situations I'm glad I have a job and can buy health insurance.

[JamesHealey]

bad dental hygiene has been linked to heart disease

look after those teeth dude, and that ticker.