No, you have missed nothing. Those are cheap but well performing transformers.
The primary inductance is a bit low, just 5H, but works very well with UL-connected EL34 PP.
I have used this type also with JJEL509 PP and 100 W comes out easily.
No sign of core saturation or anything else.
Audio Notes PP 25W OPT's ( I think they're 5k primary) Are supposed be nice so I've read and were quite affordable last I looked.
Audio Note
The Lundahl OPT's like the LL1663 & 1682 with a 40W rating and 5 & 5.5K input I would think to be quite affordable over there also. The AM versions if you could swing the necessary $ would be especially nice from reports on this forum and others.
Audio Note
The Lundahl OPT's like the LL1663 & 1682 with a 40W rating and 5 & 5.5K input I would think to be quite affordable over there also. The AM versions if you could swing the necessary $ would be especially nice from reports on this forum and others.
ebay, from a seller in Hong Kong I believe.
JS-6225HS model has 5K primary to 4, 8, and 16 ohms secondaries. I'm running the system in UL mode with a GNFB from 16ohm tab, outputs from 4ohm. As I said I'm surprised with the results.
JS-6225HS model has 5K primary to 4, 8, and 16 ohms secondaries. I'm running the system in UL mode with a GNFB from 16ohm tab, outputs from 4ohm. As I said I'm surprised with the results.
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Ian,
The trick I would recommend is to use local balanced shunt feedback to screw the best performance out of whatever output tranny you end up with.
Look at the Baby Huey scheme. It trades output tube gm for reduced rp.
The reduced rp means better drive of the primary inductance to improve the bottom end and also better drive of the shunt capacitance and leakage inductance to improve the top end.
With Ultralinear connection plus balanced shunt local feedabck I have found that global feedback is not required.
The balanced shunt local feedback does however mean that it is easier to stabilise the amp if global feedback is used, as the output tube /output transformer HF pole is shifted higher.
Cheers,
Ian (also)
The trick I would recommend is to use local balanced shunt feedback to screw the best performance out of whatever output tranny you end up with.
Look at the Baby Huey scheme. It trades output tube gm for reduced rp.
The reduced rp means better drive of the primary inductance to improve the bottom end and also better drive of the shunt capacitance and leakage inductance to improve the top end.
With Ultralinear connection plus balanced shunt local feedabck I have found that global feedback is not required.
The balanced shunt local feedback does however mean that it is easier to stabilise the amp if global feedback is used, as the output tube /output transformer HF pole is shifted higher.
Cheers,
Ian (also)
Thanks for the advice Ian. I notice that the Baby Huey is your design. well done.
I am a bit of a stickler for accurate definitions, particularly when negative feedback is involved. To accurately describe any negative feedback topology you need to specify both how the NFB is derived AND how it is applied. Terms like voltage NFB or current NFB or shunt NFB only tell half the story. The article I read about the Huey says only that it uses shunt NFB. Working out exactly what type it is is complicated by it being balanced. Perhaps as the designer you could help me out??
Edit: Forget that; I just read your explanation on another web site. Neat.
Cheers
Ian
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How about this polish manufacture, they seem to have good prices : Ogonowski.eu - profesjonalne transformatry do wzmacniaczy lampowych
Does anybody have experince with them, and the quality on there transformers?
Does anybody have experince with them, and the quality on there transformers?
Ian,
I wonder if taking something from Stu Hegeman's "book" (see H/K Cit. 2) by adding an outer, global, NFB loop of a FEW dB. might take "Baby Huey" a bit further. Core saturation is not likely and linearizing the O/P transformer can't hurt.
High gm is definitely a plus in designs incorporating loop NFB: short, long, or global. Resistance to HF error correction signal induced slew limiting is obtained.
At least they publish their La figure which many do not. Thanks for the link.
Cheers
Ian
Hello,I can recommend this: Indel TGL40/001.
TGL 40/001 INDEL - Transformer: speaker | TME - Electronic components
It is rated for 40 W but is huge and has 180 VA core. And don't care about the frequency response specified by the manufacturer.
With some 10...14 dB of GNFB this reaches beyond 100 kHz.
thanks for your comment.
Any idea of the max current who it can handle ,please ?
No information founded at Indel or TME.
Regards
Marc
I don't know, but I works fine with a pair of PL519 at 100 W and also with pair of EL34 at 70 W.
I have tested both combinations.
artsalo, I have a pair of these on hand. Do you have any links to schematics using these?
With the numbers cited above, I assume pentode, not UL operation?
With the numbers cited above, I assume pentode, not UL operation?
Does it works with a pair of 807 ?
I'm trying now to build a 807 class AB push pull with it.
B+=340v 71ma UL or triode vg=-25v.
Leak TL .. like schematic.
6N6P phase spliter builded and tested.
https://www.diyaudio.com/community/threads/6n6p-tube-focus-on.201362/page-4
Hello, there is a 2v 6A winding on the power transformer Indel tsl 180/001.IWhat is the use of this winding please ?
I was lucky back in the early 2000's to purchase a new manufacture of a pair of Dynaco Z565 UL transformers for $70 each, and glad to get them and never looked back.
They're superb!
They're superb!