Will an old Dynaco output transformer work in an Express?

[gnugear]

I've got a '50s or '60s Dynaco Tube amp and was wondering if I could use the transformers for another express build. I think the Dynaco is rated at 35 watts so it sounds right in the ballpark. I've also heard that the transformers are regarded pretty highly.

[mlp-mx6]

Wouldn't surprise me if folks recommend that you either restore that to its former glory, or sell it to someone who will. Nice stereo amp - can sound REALLY good for a home stereo. Is the chassis beyond repair?

[gnugear]

No, I'm just thinking out loud. I've had it for over a year and haven't updated it at all. Not even sure if it works but I'll figure it out. I'll most likely keep it and restore it.

In fact I took the Mullards out of it and I'm using it in my express!

[Buschman]

You should probably look on ebay at the price of a working st70 before you tear it up. I use one at home with a tube Dynaco preamp & it really sounds rich. Class A el34s!

[MarkB]

Sunn used Dynaco OTs for a while in their bass amps. I"m not sure how that would translate in a Wreck build.

[dug]

I've tried one. It wasn't an old Dynaco but a Magnaqwest that was supposed to be a dead on copy. Didn't like it. In fact I tried it in a bunch of other builds and it never quite worked. It might work for a clean amp but not for distortion. To harsh for my ears.

Anyone want to buy a Magnaqwest tranny

[LeftyStrat]

I've heard some people say that the hifi iron doesn't work well in a lot of amps, the exception being EL84 based amps. If this is so that dynaco would be perfect for a Rocket clone.

[BluzMike]

No, I'm just thinking out loud. I've had it for over a year and haven't updated it at all. Not even sure if it works but I'll figure it out. I'll most likely keep it and restore it.

In fact I took the Mullards out of it and I'm using it in my express!

Use it to build an OD-75W. Dumbles have hifi-ish power amps, and there are rumours that Alex D. used an old Dynaco tranny in his own 2 x 6550 OD.

Michael

[jblues]

the input impediance is key to the express it wants one (output transformers ) at 6k like and old plexi marshall or...like a tweed fender deluxe output trannie but the tweed deluxe is like 15 watts so maybe not but the impediance is right... the hifi output trannies are ..made to be efficient so lower impediance gives better efficiency more volume...but also more high frequencies...not good in a tranwreck design ...where the output trannie is used to mute the treble generated in the circuit...

[dobbhill]

I may be wrong, but that ST-70 trannie is rated for 35 watts full bandwith and 70 watts limited bandwith. 75 watts may be pushing it, but I use an original in my 2 x 6L6 (50-ish watts) clone with excellent results. Good advice, BluzMike.
D

[skyboltone]

I may be wrong, but that ST-70 trannie is rated for 35 watts full bandwith and 70 watts limited bandwith. 75 watts may be pushing it, but I use an original in my 2 x 6L6 (50-ish watts) clone with excellent results. Good advice, BluzMike.
D

I THINK (in other words don't quote me) that the input impedence of the Stereo 70 output tranny is in the neighborhood of 4500 ohms. Most of the guitar amp schemes I've seen call for 6000 or so. Rated at 35 watts, I'm sure it will saturate easily with a pair of 6L6's. I think that is key to full range in a guitar amp. Voice the amp for the output iron.

maybe