Hammond 1750V vs. 1750T

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psychepool
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Hammond 1750V vs. 1750T

Post by psychepool »

Now I'm checking the parts to make an AC30 style amplifier.

There's a lot of good transformers in the world but I do not have much choice because I live in Asia. Shipping cost is very high!

Maurer and Digi-Key offer free shipping when they purchase more than a certain amount.
But Hammond is the only output transformer to handle in there.
I am going to use Hammond without any other choice.

Hammond has two products for the AC30. It's 1750V and 1750T.
http://www.hammondmfg.com/guitarLineOT.htm
http://www.hammondmfg.com/pdf/EDB1750V.pdf
http://www.hammondmfg.com/pdf/EDB1750T.pdf

They said one is for the AC30 vintage and the other is for the AC30 reissue, but I wonder what the difference is.

And, there are two kinds of choke.(vintage and reissue)
http://www.hammondmfg.com/guitarLineCHK.htm
http://www.hammondmfg.com/pdf/EDB194E.pdf
http://www.hammondmfg.com/pdf/EDB194D.pdf
I also wonder what the differences are in each one.
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martin manning
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Re: Hammond 1750V vs. 1750T

Post by martin manning »

The OT differences are basically cosmetic- slightly different mounting dimensions and the leads all come out on one side on the vintage. The vintage choke is 30H vs. 5H for the reissue. I'm guessing the 5H on the reissue is a cost-cutting move.
psychepool
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Re: Hammond 1750V vs. 1750T

Post by psychepool »

Is there any difference between plastic bobbin and paper?

And vintage 30H choke is cheaper than reissue 5H. Then, what's difference between them?
And which one would be better choice? I am more attracted to reissue choke because it has metal cover.
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martin manning
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Re: Hammond 1750V vs. 1750T

Post by martin manning »

psychepool wrote: Wed Feb 07, 2018 2:53 pm Is there any difference between plastic bobbin and paper?
Some say yes, some say no. A religious discussion, I think.
psychepool wrote: Wed Feb 07, 2018 2:53 pm And vintage 30H choke is cheaper than reissue 5H. Then, what's difference between them?
And which one would be better choice? I am more attracted to reissue choke because it has metal cover.
30H would make a stiffer supply, with lower ripple voltage, it may not make much difference since it is after the plate node, but I'd be inclined to go with the vintage spec.
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didit
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Re: Hammond 1750V vs. 1750T

Post by didit »

Noted that vintage output transformer 1750V has more than cosmetic differences. The DCR & inductance specs are different, even though the nominal impedance and power specs are the same.

Best .. Ian
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martin manning
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Re: Hammond 1750V vs. 1750T

Post by martin manning »

Yes the magnitude of the difference in Lpri seems huge considering the listed bandwidth is the same for both. Test conditions are different, too. Primary DCR is not that much different; 21%.
pdf64
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Re: Hammond 1750V vs. 1750T

Post by pdf64 »

martin manning wrote: Wed Feb 07, 2018 10:10 pm Yes the magnitude of the difference in Lpri seems huge considering the listed bandwidth is the same for both. Test conditions are different, too. Primary DCR is not that much different; 21%.
I wonder if there may be a typo for one of the inductance values? eg the modern OT should be 68.2H.
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didit
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Re: Hammond 1750V vs. 1750T

Post by didit »

pdf64 wrote: Fri Feb 09, 2018 7:46 pm
martin manning wrote: Wed Feb 07, 2018 10:10 pm Yes the magnitude of the difference in Lpri seems huge considering the listed bandwidth is the same for both. Test conditions are different, too. Primary DCR is not that much different; 21%.
I wonder if there may be a typo for one of the inductance values? eg the modern OT should be 68.2H.
Makes sense. Actually how it read on my first fast read.

Best .. Ian
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