Heyboer and MM 18W Output Transformers

[Mike K]

A difference of 0.17dB.
You must be joking.

Interestingly, assuming the turns ratio of 34.1 into 8R is correct, both OTs would have a theoretical Raa of 9.3k
Adding effective DCR gives an effective Raa of 9.9k for the Heyboer and 11k for the Mercury.

Yes - it was in regards to a comment that sometimes changing an OT just makes the amp sound louder. I think sometimes it does, but not always in a bad way. Usually if something sounds harsh but louder, you'll know and not like it.


Also, yes. I looked at that. Quite a bit of a deviation from the "spec" of 8K. In my research I think it is correct, or pretty darn close. Apparently some guys at 18W had this adjusted down to 8k by Heyboer. The end result is that it lost something in the transition, or so the reports tend to be. Merc makes many other versions of this OT, but I don't own a boutique amp company with half a million to invest in OT development, so I don't know that I'll ever get to those.

[Chuck H]

It's not out of line. I appreciate the insight and I'll give it a try in the future. Right now I'm trying to decide if I really "NEED" that $150 LCR meter.

There are lines for sure. What is an avocation? A hobby? A passion? Obsession?

Like when you buy a new guitar and someone asks if you're going to sell the old one.

[nosaj]

Originally posted by Mike K View Post
It's not out of line. I appreciate the insight and I'll give it a try in the future. Right now I'm trying to decide if I really "NEED" that $150 LCR meter.

You sometimes whether you need it or not can be negated by the fact of does it speed up things. But you cannot go wrong with the Der 5000.

nosaj

do i really need that calculator and so on an so on.

[Mike K]

do i really need that calculator and so on an so on.

I have some SWEET calculators. But I never use them anymore. I do everything on a computer these days.

[35L6]

What's going to bug you more ,$150 or not getting it ?

[dai h.]

The (made in Taiwan) LCR meters selling on ebay from Japan should be from here (according to the FAQ they made an initial purchase of 10,000 units and (credit to them) passed the saving on to the consumer--this is why they are inexpensive) :

https://akizukidenshi.com/catalog/g/gM-06264/

(You can look at this page and the prices and see how good of a deal you are getting (or not).) Right now (MAY 2023) the LCR meter unit (only) is 9480 yen which is (according to today's exchange rate) USD$69.84. I bought one some years back for around half the price (in yen) but since then the dollar strengthened a lot vs. the Yen, hence the increase. Possibly, there might be something like those really inexpensive transistor testers such as this open source project ("inductances of 0.01 mH to 20 H can be detected and measured") which can be purchased for even less but I haven't really followed the situation very closely.:

https://www.mikrocontroller.net/arti...ction_(English)

p.s. something you might want to watch out for with the DE-5000 is to avoid inserting the battery (if you use one) backwards or damage can occur (what I vaguely remember according to a post from someone here)

[Mike K]

I get equal turns on both legs of the primary. There is no imbalance between the reflected impedances.

Heyboer (full primary) turn ratios:

4R: 53.6:1
8R: 34:1
16R: 23:1

Merc (full primary) turn ratios:

4R: 48.4:1
8R: 34:1
16R: 23:1


I want to repeat this measurement with a better instrument. My signal generator only puts out 1.5V, so that doesn't give me much resolution on the secondary. My variac would be nice here, but dead. I'm going to see if I can find a 15-20V transformer that I can use.


If the winding ratios are the same, which no doubt they likely are. We'd have to assume from the DCR that these are both wound very differently on both the primary and secondary.

So these are a little off - measuring using heaters I get:


Heyboer (full primary) turn ratios:

4R: 49.4:1
8R: 32:1
16R: 22:1

Merc (full primary) turn ratios:

4R: 44.9:1
8R: 32.3:1
16R: 22.2:1