Question about Output transformers
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Question about Output transformers
Hi all
I'm a bit of a newbie to the amp building seen. My project at the moment is a TW rocket.
While looking at OT's, I've just a quick question..
I'm looking at these two options from Hammond (easy to source in the UK)
The first is the model 1750v:
http://www.hammondmfg.com/pdf/EDB1750V.pdf
It's basically an AC30 replacement, so it's 30W with a primary impedance of 4K.
Now I happened to stumble across this model, the 1650N.
http://www.hammondmfg.com/pdf/5c0051-52.pdf
This seems like more of a hi-fi transformer - which I believe is more of a rocket trait. And has a primary impedence of 4.3K - which I also understand is that of Ken's rocket. It also has secondary taps at 4, 8 and 16ohms. This transformer though is rated at 60W.
What impact does this have if any?
Thanks
I'm a bit of a newbie to the amp building seen. My project at the moment is a TW rocket.
While looking at OT's, I've just a quick question..
I'm looking at these two options from Hammond (easy to source in the UK)
The first is the model 1750v:
http://www.hammondmfg.com/pdf/EDB1750V.pdf
It's basically an AC30 replacement, so it's 30W with a primary impedance of 4K.
Now I happened to stumble across this model, the 1650N.
http://www.hammondmfg.com/pdf/5c0051-52.pdf
This seems like more of a hi-fi transformer - which I believe is more of a rocket trait. And has a primary impedence of 4.3K - which I also understand is that of Ken's rocket. It also has secondary taps at 4, 8 and 16ohms. This transformer though is rated at 60W.
What impact does this have if any?
Thanks
Re: Question about Output transformers
The 1650N sounds like the better option. 4.3k is correct but the A470 OT that Ken used was rated at 70W iirc.
Eardrums!!! We don't need no stinkin' eardrums!
Re: Question about Output transformers
Thanks. And obviously the fact that the wattage is double what is required (60 V 30), won't have an impact on sound? It's just what the transformer can handle in terms?
I'm looking into a PT too. I am a little confused as to the correct high voltage spec. for the Rocket. Some mention 250V or 260V. From what I read it seems higher voltages give more headroom and I imagine sound more 'brown' at lower voltage? What have people been using and how do you find this effects the sound? What did Ken use?
I'm looking into a PT too. I am a little confused as to the correct high voltage spec. for the Rocket. Some mention 250V or 260V. From what I read it seems higher voltages give more headroom and I imagine sound more 'brown' at lower voltage? What have people been using and how do you find this effects the sound? What did Ken use?
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Re: Question about Output transformers
I'm not sure what Ken used, but the Rocket uses 4 x EL84s. Plate voltage is lower for a Rocket/Liverpool than say an Express.
Re: Question about Output transformers
I used the 1650N on a Rocket build and it sounds pretty good.
Re: Question about Output transformers
Hi,
i´m a little confused: didn´t has Kens Rocket ~6k6 primary?
I use a Hammond 1650P in the Rocket. Is this way to much? Sound is very streight, very nice and easy bloom and huge bottom end. Only the cleans I cant get "fendrish"- with LP though. V1 and V2 are 7025 to cool him down a bit
Hans-Jörg
i´m a little confused: didn´t has Kens Rocket ~6k6 primary?
I use a Hammond 1650P in the Rocket. Is this way to much? Sound is very streight, very nice and easy bloom and huge bottom end. Only the cleans I cant get "fendrish"- with LP though. V1 and V2 are 7025 to cool him down a bit
Hans-Jörg
Re: Question about Output transformers
I'm not sure hans-jörg, from what I've read he used a 4.3K primary.
Matt D, did you use Hammond for the PT as well? Can I ask if so what model you went for and why?
Matt D, did you use Hammond for the PT as well? Can I ask if so what model you went for and why?
Re: Question about Output transformers
6.6K was the Express. 5.2K Liverpool. 4.3K Rocket.
Eardrums!!! We don't need no stinkin' eardrums!
Re: Question about Output transformers
I used RJ's Edcor part for for the PT. I didn't go out looking for the 1650N specifically but a friend sold me one he wasn't using for cheap. I wouldn't say the amp I made with it is particularly magical or mind blowing but it holds it's own nicely next to my bandmate's English-made 90's AC30. Everyone who plays it says something like "Hey, this amp sounds pretty good," rather than "I must have this amazing amp."
Re: Question about Output transformers
damned! Looks like I had the Express sheets in hand when I ordered for Rocket. I built both amps one after another and mixed it up - somehow. Anybody else with such a stupid mistakedartanion wrote:6.6K was the Express. 5.2K Liverpool. 4.3K Rocket.
But I will swap them. Cince I had the Express I allways used the half of secondary (16 Ohm speaker - 8 Ohm at the amp) to meet the right impedance. But now I have the reason to change on by another.
My Express (K60) OT shows 4,2k prim. (measured), and is a Marshall 50W style (probably a replacement for 50W Plexi). I think it will work with 4xEL84 same as with 2xEL34 - or am I misleaded?
BTW: both are great amps even with slightly mismatched impedance
Last Question: because I don´t know when I find time to swap them: Am I right to use the 16 ohm out for a 8 Ohm speaker to come to a propper matching? Or is this to much too? That would be 6k6 down to 3k3, right? To low I find.
Best
Hans-Jörg