Alan HQ1313 200w tube linear amp

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Poteroa
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Alan HQ1313 200w tube linear amp

Post by Poteroa »

Hi all!

I inherited a Linear amp made by CTE international (Alan/Midland) some time ago thats been laying on the shelf.

Found it the other day and started to check if it is still in operational condition, well it wasn't.

Internals are really simple, as tube amps normally are, almost idiot proof and easy to repair.

Well, in this case just replacing few caps does not help, transformer is shorted, badly.

Seems that it was either burned with dead key on a friday night after few beers or... Well nothing else comes to mind knowing who had it before. :P

I contacted midland europe, asked for transformer specs, and they said that they have no information about the transformer.

I think they just couldn't be bothered with my request..

So the question is, does anyone have one that they replaced the transformer to a new one, or a working one that they could send me the voltage/amp info from the input line for the EL509 tube..?

Help would be much appreciated.

Pete

P.S. manual attached
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Last edited by Poteroa on 12 Dec 2018, 15:20, edited 1 time in total.
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ch25
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Re: Alan HQ1313 200w tube linear amp

Post by ch25 »

Pretty easy to rewind. I'm sure there are some companies in UK could do that. I had re-winded much bigger transformers cheap.
https://www.google.com/search?q=transformer+repair+uk
Chris
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Poteroa
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Re: Alan HQ1313 200w tube linear amp

Post by Poteroa »

ch25 wrote: 11 Dec 2018, 17:27 Pretty easy to rewind. I'm sure there are some companies in UK could do that. I had re-winded much bigger transformers cheap.
https://www.google.com/search?q=transformer+repair+uk
Chris
Hi Cris!

I would have hoped that someone still had a working one that I could have the measurements from the tube input line on idle and on full load. The control circuit voltage is 6.3vac at 2 amps.
Thinking about a ring transformer as an upgrade to the old one, if it just fits there and can shield it from the tubes heat.

What I have found, is that the voltages are close to 275-330vac by similar circuits that are based on the same tube EL509 and running at 150-250w PEP.

I have never tried to rewind a transformer, main problem would be the lack/glue or what ever they use to make a solid lump and how to remove it without destroying the delicate plastics. I already have the windings thickness measured, so only thing is to figure out how to open it up.. And well put it back again. :D

I think I will share the original schematics here, as it can not be found anywhere in internet. So do I have the only copy? :think:
Poteroa
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Re: Alan HQ1313 200w tube linear amp

Post by Poteroa »

So I just bit the bullet..

Dismantled the transformer and the primary coil.

Took over 2 hours to remove the "EI" iron core and 1 hour to unwind 685 rounds of copper wire.
Used soldering station hot air and carpet knife blade going through every "E & I" piece and removed them one by one.
After that just heated the core and gentle tapping around until the "pack" felt loose with soft plastic mallet, then the first "E" piece out with pliers.
Then it was quite fast to remove the rest of the pieces.

Took measurements and taped the wire after every 20 turns / cut after 100 turns. In the end had 610 unwinds of primary coil, that had 75 winds on top of it that was not in use.. Maybe it was meant for some additional use, but not used with this amp.

This is the first time ever I try to rewind a transformer, so let's see how it goes..

Failure was obvious, the primary coil had overheated on top section and the enamel came of very easily, some of the plastics had melted, but its still usable.

For someone who might need to do it later, some data.

Primary side windings:

220-250v side (closest to core)
0.4mm / 26awg, 610 winds (weight of 135 grams)
Second for additional output of ???v and protective layer on top of primary layer?
0.4mm / 26awg, 75 winds (did not take weight of it, as I will leave it out)

Secondary side I don't need to touch as it is not shorted and the measurements are ok.

Next thing is to find some high temp varnish, 0.4mm / 26awg wire and build a winding machine from something.

Was thinking about to add a fan inside, so can continue the dead key tradition with this amp. :lol:
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ch25
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Re: Alan HQ1313 200w tube linear amp

Post by ch25 »

Great job. Fan is a must. I owned 1313 back in a day, 120mm fan fits perfect on the bottom, under a lamp. I made a holes underneath for better air circulation. Worked fine on am dk.
Keep in mind, that you must use special transformer varnish to avoid fire.
Chris
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Poteroa
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Re: Alan HQ1313 200w tube linear amp

Post by Poteroa »

ch25 wrote: 14 Dec 2018, 06:21 Great job. Fan is a must. I owned 1313 back in a day, 120mm fan fits perfect on the bottom, under a lamp. I made a holes underneath for better air circulation. Worked fine on am dk.
Keep in mind, that you must use special transformer varnish to avoid fire.
Chris
Thanks Cris, lets see how it goes.
I found the proper wire, with heat resistance of enamel up to 155deg/c. But the damn varnish seems to be an issue, none of the electronics stores here in Finland sells them.
I found some other varnish that can take 120deg/c, so I think that should be enough. Do not want to go to epoxy, as then its final..

Adding the fan of course helps a lot, so I think I will be fine.
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Re: Alan HQ1313 200w tube linear amp

Post by Poteroa »

So, finally got the stuff I needed. Some hassle again with the postnord parcel service..

I found a 3D print model from internet of a nice handle driven winding machine and did some changes to suit my 28x50 core, it came out nice.

Then did arduino rev counter so that I did not need to mess my head with numbers while winding, better to do one task at a time.. :lol:

So after painful 1.5h task, the core had now 650 turns, (added more as the voltage in 80´s was close to 210-215 volts from the grid, that is nowadays 230-240 volts. So a slight "upgrade" at the same time.

After the dreadful task the core itself took only 20 mins to reassemble and the pack was ready.

I decided not to use any varnish as it can be added later, also the EI-pieces are just bolted together.
The transformer does not make any humming noise on idle, so lets see when the load is on..

Tested the transformer without load, and tube heating + relay control was bang on 6.3vac, the tube side voltage was at 283vac, so looking at the specs of EL509, just on the edge of 200W max output.

Summary..

It really felt that this project can go badly to tits, but with patience (which I am not good at), some quality tools, even self made, this can be easily done at home.
Next phase is to slowly heat up the transformer and use varnish to protect the windings, maybe add the fan too as Cris suggested.
One thing that is better now, is that the old layer on top of the primary winding is now left out, which helps to cool the core.

All in all, this was a nice project to do, and if anyone is thinking that any device, what ever it is, is waste because of the transformers gone bad, you are wrong. Just bite the bullet and fix it!

What it took?

0.4mm copper winding wire, 12€
3d printing the machine, 6 hours, filament cost 1-2€
arduino Uno, coding 45 minutes, 5€
unwinding/winding, 6+? hours, priceless :lol:

Next transformer will be much faster and much easier as do not need to learn the stuff on the way.. :wave:
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cb4ever104
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Re: Alan HQ1313 200w tube linear amp

Post by cb4ever104 »

Thanks for the info . Looks like something I'd like to try , but my BV-135 is still working at the moment . So I'll need to wait till it dies :)

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Poteroa
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Re: Alan HQ1313 200w tube linear amp

Post by Poteroa »

cb4ever104 wrote: 18 Jan 2019, 11:04 Thanks for the info . Looks like something I'd like to try , but my BV-135 is still working at the moment . So I'll need to wait till it dies :)

Sammy
Just do a few hour dead key in a sauna, I think that would be more than enough :lol:

Just be sure to get quality wire, mine was made by "Block" germany, good stuff..

Cheers, hope to find some New project soon. :thumbup:
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