6EM7 ressurection.

What people are working on at the moment
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Dave the bass
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#31

Post by Dave the bass »

Quick question, is there a source for a simple 0-5V @2A (min) mains TX in the UK? I'm looking for a suitable TX to power the heater on a GZ34.

Ta,

DTB
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Nick
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#32

Post by Nick »

I an only think of the Hammond 266M5 from Phillip

http://www.bluebellaudio.com/

Though if you haven't speken to him before, I hesitate to suggest what would happen if DTB and Phillip get talking about things musical.

(this will make sense to those who have spoken to Phillip :-))
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#33

Post by pre65 »

Nick wrote:I an only think of the Hammond 266M5 from Phillip
http://www.bluebellaudio.com/
)
That is what i use on my PT15 monoblocks.
The only thing necessary for the triumph of evil is for good men to do nothing.

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G-Popz THE easy listening connoisseur. (Philip)
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Dave the bass
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#34

Post by Dave the bass »

Thanks Nick and Phil,

That'll do, I also found a handy 5V/6.3V filament here at Mikes site http://www.livinginthepast.demon.co.uk/xformer.html

Nick, I've spoken to Philip at BB once before.

The phone melted before we could finish our conversation, I think it was a 'draw' in the end :wink:

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#35

Post by IslandPink »

That's a nice Site Dave . Do we know Mike H from anywhere else ?

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#36

Post by pre65 »

Hi-i have met Mike a couple of times when collecting bits (i think DTB has met him as well ) as he lives near my Mum.(Basildon).

He was the man behind the Maplin valve amp equipment and he did post on the WD forum some time ago.

He "rescued" a lot of WAD equipment that was due to be "skipped" and he supplied me with a couple of Audionote PP transformers which i use on 832A and some mains toroids from a Kit88 which i use on the ECL82 Doddington.
The only thing necessary for the triumph of evil is for good men to do nothing.

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G-Popz THE easy listening connoisseur. (Philip)
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#37 Nice

Post by IslandPink »

Nice one Phil.
Well worth supporting .

MJ
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Dave the bass
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#38

Post by Dave the bass »

IslandPink wrote:That's a nice Site Dave . Do we know Mike H from anywhere else ?

MJ
Yes Mark,

Mike as Phil says lives just the other side of the water (Thames) from me. I popped down to buy the chokes I'm using in 6B4G directly from him. They're ex WAD 2A3 PSE PSU chokes. He's fine with personal callers. Maybe we could invite him to this forum?

As an aside....Back in the early 80's I used to work at the ILEA with an Electronics Tech also called Mike H (Henniker), a crazy bearded Scot that used to live in Plumstead (SE London) but I've lost touch with him now, I'd love to track him down and have a chat again. Brilliant Valve engineer but loved a dwinky and tuned Hillman Imps that blew up a lot!

Where are you now Mike H?

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#39

Post by Dave the bass »

Looking at the specs of GZ34 there's a limit on the amount of capacitance on the cathode, 60uF.

I was feeding the SS rectifier output into a choke with just a small 6uF tweak cap to lift the voltage then into a 10H Choke then a bank of serised 330uF 385V 'lytics. Is that arangment still OK for a GZ34?

I'm still putting my order together, things hve been very busy at work and I'm out the workshop a lot at the mo hence radio silence (you lucky peeps :) ).

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#40

Post by Nick »

Yep, the choke "hides" the caps after it from the rectifier.
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#41

Post by Dave the bass »

Ta Nick,

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#42

Post by Dave the bass »

Got my bits from Rabid the other day (non-inductive resistors, GZ34, Octal base and the like) and go to pick up the GZ34 5V/6.3V heater TX tonight then it's all systems go tommorow lunchtime to try and complete the upgrade/stoppensparken on 6EM7 in time for Owsfest.

Ooo, exciting innit, not long to go now.

DTB
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andrew Ivimey
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#43

Post by andrew Ivimey »

The GZ34 route should bring a lovely improvement over SS, but we'll see!

maybe its just an aesthetic thing, though! ;-)
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#44

Post by Darren »

Normally I prefer valve rects, but on my last build SS turned out to be a big improvement overall.

I think it's just one of those things, never know till you try.
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#45

Post by andrew Ivimey »

I reckon that as SS can give you so much more current, it can make an amp, particularly a PP one, sound more powerful.

just for example; Philip's 832pp has SS rectification and has clout. The one I built had GZ34 but lacked the welly.

delicate little SEs may glean more detail and subtlety from using what is actually a better designed PSU. i.e. valve rectified, preferably properly choke loaded.

Still, there seems to be (almost) no unbreakable rules on this.
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