bad 784 139 output transformer

BLOOZE · Post by **BLOOZE** » Thu Jul 23, 2009 8:54 am

hello

my marshall jcm 800 2204( build in 1983) has a very bad thin sounding(lots of treble) 784 139 output transformer.

I have changed the transformer years ago with a 784 139 from my silver 2554(build in 1987).

Since then the jcm800 sounds very very good and i love this amp.

Do you think after a repair (rewind) the 784 139 output transformer will sound as good as the 784 139 from my silver 2554(build in 1987).

Right now I have installed a marstran 784 128 which sounds good too but my 784 139 from my silver 2554 is really magic.(maybe because I play this transformer for over 20years and my ears are used to the sound )

thank you

Big Mike · Post by **Big Mike** » Thu Jul 23, 2009 3:05 pm

I wouldn't bother with a rewind, that'll cost 400 bucks or so.

Mars Hall · Post by **Mars Hall** » Thu Jul 23, 2009 6:30 pm

You could send it off with your "magic" one and have them build it to that spec. That don't always mean they'll sound the same but it would be closer than buying one off the shelf.

I'm suprised your Marstran isn't more to your liking.

BLOOZE · Post by **BLOOZE** » Thu Jul 23, 2009 8:05 pm

don t get me wrong i like the marstran too,and i think i will order a marstran 784 139 too.

i will built a jmp50 anyway .

but i wonder why the drake 784 139 from 1987 sound so much better then the 784 139 from 1983.

regards

novosibir · Post by **novosibir** » Thu Jul 23, 2009 8:27 pm

Can't imagine, that you like the Drake 784-139 over the Marstran 784-128
I've tried the Marstran once and simply was overwhelmed, although I've already heard lots of orig. Drakes before.

From where comes the magic in YOUR Drake?

Larry

BLOOZE · Post by **BLOOZE** » Thu Jul 30, 2009 9:11 am

After playing the marstran 128 awhile I like the 128 more then the drake 784 139.
After two-day s I changed my mind.
I have played my drake 139 over 20 years everyday so I was really used to that sound.
(I have ordered a marstran 784 139 too and will put them all on switches to test them side by side)

Roe · Post by **Roe** » Thu Jul 30, 2009 11:24 am

remember to break in the marstran trannies

BLOOZE · Post by **BLOOZE** » Thu Jul 30, 2009 11:43 am

Roe wrote:remember to break in the marstran trannies

that s what I thought too, but I thought nobody would believe

Structo · Post by **Structo** » Thu Jul 30, 2009 1:31 pm

How does one break in a transformer?

And what changes do you hear?

Roe · Post by **Roe** » Thu Jul 30, 2009 2:35 pm

Structo wrote:How does one break in a transformer?

And what changes do you hear?

let it get through a lot of heating cycles and put some signal through it

BLOOZE · Post by **BLOOZE** » Sun Aug 09, 2009 4:43 am

To my ears the 784 128 has changed the sound in the first 100 hours and sounds really good now (less treble, has lost the stiffness, more alive)

Hard to describe with words but it feels good

Structo · Post by **Structo** » Sun Aug 09, 2009 2:33 pm

But I wonder how you can tell if it is the OT breaking in or the caps and other components settling in after 50-100 hours?

Unless the only thing you changed was the OT and then noticed the difference.

BLOOZE · Post by **BLOOZE** » Sun Aug 09, 2009 3:10 pm

Structo wrote:But I wonder how you can tell if it is the OT breaking in or the caps and other components settling in after 50-100 hours?

Unless the only thing you changed was the OT and then noticed the difference.

The only thing I have changed was the 784 128,so I know what has changed the sound.

I had the same experience with my custom shop strat (with caps, effect pedals ,speakers ,with my levis501

) , I play everyday and after 6 months the guitar starts to sound really good.(and gets better everyday)

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