I gave them a set of very basic specifications, basically operating current, plate resistance, winding ratio (1:1) and that I wanted a bi-filar winding and amorphous core. They did the rest.
I use their transformers in pretty much anything I do of significance these days. (My system is now tri-amped and is full of MM transformers. I also put them in the amps and line stages I have built for others.)
They've done 20K:600/150, lots of output transformers and the power transformers for some of my more deluxe projects.
I recommend them highly. (Feel free to mention me)
I use their transformers in pretty much anything I do of significance these days. (My system is now tri-amped and is full of MM transformers. I also put them in the amps and line stages I have built for others.)
They've done 20K:600/150, lots of output transformers and the power transformers for some of my more deluxe projects.
I recommend them highly. (Feel free to mention me)
It is important instead. Although not the main source of distortion it has an impact even if you stay away from grid current. The ideal transformer would have zero dc resistance....
For the rest I agree on the fact that the LL1635 is decent transformer, very good for the price (especially if you buy at 1/2 price like me!
) but there is surely better stuff like MM et al. around.....
Sorry , I don't mean to take you to task, just want to be sure I am not taking you too literally . . . You really didn't specify Vp or desired primary impedance?
Is there any point in asking what it is you like about them?
For headphone amp? How did they work out? 20K done well isn't anything to scoff at.
Well, that's why I'm asking all these questions. After spending a fair bit of time working on Michael K's M2 (35TG) circuit I thought to finish up with a good OT and ran into resistance when I specified the circuit's original 5K, a lower primary impedance than they felt right for the tube. Rather than argue with them about it I finished the amp without their help. Still, I'd like to know what the hubbub is about.
It is important instead. Although not the main source of distortion it has an impact even if you stay away from grid current. The ideal transformer would have zero dc resistance....
For the rest I agree on the fact that the LL1635 is decent transformer, very good for the price (especially if you buy at 1/2 price like me!
It is no more or less important than in any other driver topology, but I agree that lower in general is better provided the other transformer trade offs are considered as well. (leakage inductance/capacitance/magnetization current in the core, etc.) The MM were a substantial improvement sonically and reduced measured distortion. The D3A used does not seem like a particularly good choice as a driver in an application where more than a couple of mA of grid current flow.
Since this was a 1:1 transformer I specified the driving impedance (rp), vaguely alluded to ~5K impedance, told them the expected frequency response and limits along with maximum AC amplitude into the next stage. I told them I needed this level of performance at a plate current of 20mA, I did not specify plate voltage. I don't generally specify primary inductance as I don't know what they can achieve, I let them tell me and I then let them know if I think that is sufficient. (It is usually more than I expected)
The 20K:600:150 is in my line stage and those of several others.
They're easy to talk to, helpful and are very knowledgeable. I like that they build high quality transformers to my specifications, and that in comparatively moderate quantities they are reasonably priced. They easily meet their specifications, and sound good. (Neutral and detailed)
This post is stuffed with nonsense
Transformers wound on amorphous or nanocrystalline cores are superior in transparency and reproducing detail.
Amorphous core transformers need some more core mass compared to high quality (HiB) silicon steel and nanocrystalline core transformers to compensate lower permeability.
When manufacturers charge 10x the price for transformers wound on amorphous or nanocrystalline cores you are fooled.
To give an idea, here is a simple price comparison for the different high quality core materials, all c-cores:
When a HiB c-core, 0.23mm lamination, would cost 15 euro, an iron based amorphous c-core would cost some 20 euro, and a nanocrystalline c-core some 25 euro. All cores the same dimension.
For one typical 300B single ended output transformer cost price for the cores would be 60, 80 and 100 euro for respectively HiB, amorphous and nanocrystalline (I use four cores for one transformer in a stacked double c-core configuration). Then the cost of labour for winding, assembling and so on, which is more than the cost price of materials (cores, magnet wire and assembling materials).
So, an output transformer with the more expensive core materials is in the end not necessarily more than 10% (amorphous) or 20% (nanocrystalline) more expensive than the HiB silicon steel core transformer.
These comparisons are based on what I, as a winder, pay for the cores. Maybe other winders pay more for the cores, or they have a different price policy.
Have you used Nanocrystalline in a power transformer? like for B+ application?
Hi Analog_Sa,
Can you please tell me what specs did the transformer winding guy used to wind the transformer?
Secondly how much flux max is recommended for power transformer? Consider HiB or standard CRGO, Amorphous, Nanocrystalline?
A transformer guy willing to wind a power supply transformer on an amorphous core demonstrates how crazy (stupid actually) audiophiles can be....
Power supply transformers (for linear supplies) work on 50 / 60 Hz; amorphous cores are meant to work on much higher frequencies.
Info on max flux density for the various core materials is readily available on www.
But to repeat:
- standard CRGO some 1.8T;
- HiB silicon steel a little over 2T;
- amorphous 1.56T;
- nanocrystalline 1.23T.
To stay in the safe zone, preventing core saturation in case of highish line voltages (or primary voltage swings in case of audio transformers), it is wise not to wind for more than some 70% of max T.
That's why many commercial toroidal power transformers suck because manufacturers look for maximum efficiency. Toroidals have no airgaps, so they are comparatively very sensitive to over voltage. Therefore they tend to buzz, rattle a.s.o. when the core saturates.
Don't go over 1T if you want a good quality toroid.
Power supply transformers (for linear supplies) work on 50 / 60 Hz; amorphous cores are meant to work on much higher frequencies.
Info on max flux density for the various core materials is readily available on www.
But to repeat:
- standard CRGO some 1.8T;
- HiB silicon steel a little over 2T;
- amorphous 1.56T;
- nanocrystalline 1.23T.
To stay in the safe zone, preventing core saturation in case of highish line voltages (or primary voltage swings in case of audio transformers), it is wise not to wind for more than some 70% of max T.
That's why many commercial toroidal power transformers suck because manufacturers look for maximum efficiency. Toroidals have no airgaps, so they are comparatively very sensitive to over voltage. Therefore they tend to buzz, rattle a.s.o. when the core saturates.
Don't go over 1T if you want a good quality toroid.
It was on a Hitachi AMCC400 with 2x300v + 2x24v windings. The winder certainly knew the specs of the core as he had previously and rather successfully made chokes and audio transformers on the same core.
The transformer has no technical issues at all, no buzzes, does not draw excessive current when unloaded. The sound otoh is bright and bass light.
At the same time i have friends i find trustworthy, who swear by their amorhous power transformers. Same core, different winders. Yes, very inconclusive.
Most of the chokes and signal transformers i use are either on amorhous or nanocrystalyne cores, so it is not like i am unfamiliar with the sound signature or the need for an extended break-in.
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It is true that cores are meant to be used for higher freq signal transformers than power transformers but the question is when moved from standard CRGO to HiB the SQ changes considerably so as when moved to Nickel based power transformers the improvement is even more as its seen on Audio Note transformers.
Just thought why not try amorphous of nanocrystalline based but like said by analog_sa that the sound thinned in bass and so.
Who has done the winding of the amorphous power transformer.
A core with high freq capability also passes noise from primary to secondary so if that happens with amor/nano trafos?
Secondly is there any benefit in winding the transformer in bifilar for audio power transformer? and output transformer? or even signal coupling transformer?
I can't add anything re core materials, but I have toyed with a couple of affordable SE opt on my 833a amplifier.
An earlier comment mentioned they were low impedance and hence the opt should be easy to optimise. Low imp is obviously subjective, and the Ra differs with anode voltage. I'm running at 1300, I know magz was twice that. I can use 7k opt I believe Magz uses 11k? Anyhow with cheaper opt getting flat to 20k without using fbk is not trivial. I'd strongly suggest using tubelab style MOSFET follower to drive them. Don't be put of by some of the rather poor, if expensive commercial amplifiers out there using 833a. They can measure and sound good.
An earlier comment mentioned they were low impedance and hence the opt should be easy to optimise. Low imp is obviously subjective, and the Ra differs with anode voltage. I'm running at 1300, I know magz was twice that. I can use 7k opt I believe Magz uses 11k? Anyhow with cheaper opt getting flat to 20k without using fbk is not trivial. I'd strongly suggest using tubelab style MOSFET follower to drive them. Don't be put of by some of the rather poor, if expensive commercial amplifiers out there using 833a. They can measure and sound good.
Are you asking for a name and address?
It is not anyone you may ever encounter.Bifiliar power transformer would be dangerous and probably pointless. The only case where a bifiliar signal transformer makes sense appears to be a 1:1 interstage.
You are right that the bandwidth of an amorphous power transformer is wider than a similar construction using silicon steel lams. It is also more likely to saturate due to dc on the mains.
Are you asking for a name and address?
Bifiliar power transformer would be dangerous and probably pointless. The only case where a bifiliar signal transformer makes sense appears to be a 1:1 interstage.
You are right that the bandwidth of an amorphous power transformer is wider than a similar construction using silicon steel lams. It is also more likely to saturate due to dc on the mains.
i made an isolation power traffo, 500 va, 240:240 vac using biffilar winding, the traffo still lives today after more than 10 years...
and even for traffo secondaries, i used bifilar windings to exactly locate the center taps...
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