DHT Heater using VCCS - PCB or Kit (Possible Group buy)

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Andrew
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#781

Post by Andrew »

I use a 9v 30VA transformer from Farnell, I'm sure Rapid have something similar.

25Va might be OK, its 2.77A for both secondary windings in parallel, or 1.38A per secondary on its own, but that doesn't count for losses. A 300B heater needs a nominal 1.2A.

Personally speaking a 30VA looks a better bet. Rapid might even be cheaper.

Andrew
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Michael L
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#782

Post by Michael L »

Ok will get a 30VA. I have the 25VA already but I would rather
spend a few quid than have any doubts. Thanks Andrew
Andrew
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#783

Post by Andrew »

Well, if you already have a 25VA then try it first, see if it drops out of regulation or gets too warm; a quality transformer might be OK.
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#784

Post by Andrew »

From an 18v transformer :) Joint effort with Nick who is to blame for the board on the right.

Arise sir goer!

Mark, you up for a listen?
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pre65
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#785

Post by pre65 »

Nice to see the pot. :lol:
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Andrew
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#786

Post by Andrew »

Its so I can adjust the input voltage on the prototype, no really it is, no tweakers on the final thing!
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#787

Post by Andrew »

For the avoidance of doubt I don't expect the final version to occupy as much real-estate as the prototype.

Andrew
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Ray P
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#788

Post by Ray P »

Andrew, just thinking out loud about a possible project at the moment; are there any pcbs/kits for the 'small' board still available - suitable for a single 300B. Cost?

Cheers

Ray
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#789

Post by Andrew »

Yes, I still have a few left, I would need to work out a price for the kit, if that's what you want?

cheers,

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Ray P
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#790

Post by Ray P »

Andrew wrote:Yes, I still have a few left, I would need to work out a price for the kit, if that's what you want?

cheers,

Andrew
Kits would be good.

Ta

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Ray P
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#791

Post by Ray P »

Andrew, what would you say if I said I needed perhaps 16-20 of the small supplies?

Ray
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#792

Post by Andrew »

Ray P wrote:Andrew, what would you say if I said I needed perhaps 16-20 of the small supplies?

Ray
Err, let me count up how many PCB there are left?
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#793

Post by Ray P »

Andrew wrote:
Ray P wrote:Andrew, what would you say if I said I needed perhaps 16-20 of the small supplies?

Ray
Err, let me count up how many PCB there are left?
Just by way of explanation, you may recall my 300B OTL amps, well a US based friend and I are contemplating a variation on that theme.

Could make do with eight small and four large (I already have four of your large boards that I didn't need to use)?

I guess kits will be problematic so PCBs and a BOM will be fine if you can manage that, otherwise, would you share the files so I could get a batch made up?

Ray
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#794

Post by Andrew »

I should be able to accommodate, but it I don't want to do a kit for that many. I will include the low ESR capacitors as I bought enough to do the boards, I can PM to sort details if that works.

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#795

Post by Ray P »

Sounds good.

PM me with what you've got and I can discuss with my chum how we want to proceed.

Cheers

Ray
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