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Output transformer

 
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guitarboy
Guitar God


Joined: 09 Dec 2001
Posts: 137

PostPosted: Thu Sep 19, 2002 5:48 am    Post subject: Output transformer Reply with quote

Does anyone know how much abuse the output transformer can take before it starts to change it's function (become a short!).


OK embarrasing story time - My amp has three output jacks in a row - 2 speaker outs and 1 reverb jack.
Now personally I think this is very poor design because sooner or later - yup the reverb gets plugged into the speaker out and vice versa.

So I've trashed the spring reverb input transducer... fo sho!
But luckily it's only about 120 windings so will be doing the repair by hand.

Now the thing is the amp is still working OK but I was wondering if anyone has any idea how much grief and for how long (I suspect it's more of power issue) you can give the O.T. before it starts taking exception to the treatment??


cheers
GB
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loverockerUK
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PostPosted: Thu Sep 19, 2002 8:07 am    Post subject: Reply with quote

null

Last edited by loverockerUK on Sat Mar 13, 2004 4:53 am; edited 1 time in total
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guitarboy
Guitar God


Joined: 09 Dec 2001
Posts: 137

PostPosted: Thu Sep 19, 2002 11:08 am    Post subject: Reply with quote

Oh yes it failed and short-circuited!

Poor little thing was all blistered and swollen - ouch.

The enamel had burnt away but the copper was still intact so it was a proper short as it were.

I don't think cranking the volume to see what was up helped - you know that: mmmm it's acting a bit funny I know ......CRANK!


Anyway cheers Barry - looks like I may have gotten away with it then,
guess I'll find out at the next gig!

GB
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loverockerUK
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PostPosted: Fri Sep 20, 2002 2:05 am    Post subject: Reply with quote

null

Last edited by loverockerUK on Sat Mar 13, 2004 4:54 am; edited 1 time in total
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guitarboy
Guitar God


Joined: 09 Dec 2001
Posts: 137

PostPosted: Mon Sep 23, 2002 6:08 am    Post subject: Reply with quote

Did a gig on Sat night and rocked even without the verb!
But I did miss it a little - wasn't quite as lush as usual.

So looks like all is well with the amp for now - just have to source some
winding copper to get the verb back.

The amp is a Studiomaster valve leadmaster - anyone who has one of these should be saying at this point - but they sound like s**t!

Yes they do if they are stock - they sound complete b****x for anything other than clean sounds.

However they have all the right ingredients: 5x 12AX7(inc verb) preamp 2x 6L6 power amp - and with only a few minor mods you can turn these amps into gorgeous sounding boogie type combos.

What's really odd is that the original design had the right architecture but completely balls'd up on the signal filtering, there are some seriously flawed design decisions in them.

I have a complete set of mods for these now which turns them into tone devils! If anyone has one of these and wants the mods - it'll cost ya - but it's worth it

Oh and if Studiomaster want the mods it'll cost them even more

GB
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orb0077
Plucker


Joined: 27 Oct 2002
Posts: 1
Location: OHIO-USA

PostPosted: Tue Nov 05, 2002 9:18 am    Post subject: Reply with quote

I used to repair amps for years / the output trans.( also the power transformer and most other transformers in amps are all about the same. The difference is the number of wines in the coils. When you short the trans it in turn shorts the coil and it then heats up and then melts the coating on the wire. In time this will cause the trans. to fail! They can be shorted alot before they fail. This is why over a period of time all trans. will fail !! It's all in how much they are used and how hot they get!
I used to repair tube amps in the **'s
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guitarboy
Guitar God


Joined: 09 Dec 2001
Posts: 137

PostPosted: Tue Nov 05, 2002 11:10 am    Post subject: Reply with quote

Cheers Orb,

the **'s - when was that exactly

Just as a quick heads up I sourced some copper from RS - it was a little thinner than the original but that just means I get a bit more drive out of the beast.

All is now sounding lush once more

GB
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jpo1953
I only know 3 chords


Joined: 09 Sep 2001
Posts: 24

PostPosted: Mon Apr 07, 2003 4:19 am    Post subject: Reply with quote

I used to build valve amps in the 60's (Mullard designs) for hi-fi & I once had an output trannie blow up when the speaker leads fell off - it started playing the music just before it went! very tinny sound though
Joe
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Lee
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PostPosted: Mon Apr 07, 2003 8:43 am    Post subject: Reply with quote

Tube amps are like Ferraris - high maintenance but worth every penny if they're running good
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mat-with-one-t
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Joined: 15 Dec 2004
Posts: 1

PostPosted: Wed Dec 15, 2004 9:36 pm    Post subject: studio master Reply with quote

Hey guitarboy- I've found one of the studiomaster amps for sale, and was wondering about all these mods you mentioned. Is it woth a look at one third of the price of a MArk series Boogie from that era?
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