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Old 31st March 2003, 08:41 AM   #11
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hi 45 driver 45,

for your project. I try 1:1 & 1:2 interstage already.
If the driver tube had enough power pls try to use 1:1.
The 1:2 winding will loss a little bit of high frequency air.
I compare it in my AER to test. It made me more easy to hear the different.
For the structure, 1:2 winding will cause the increase of capacitance so the high freq will los more than 1:1.
pls see the photo, I use this speaker to hear the high freq different.

thanks

Thomas
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Old 31st March 2003, 05:34 PM   #12
Joel is offline Joel  United States
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Default Re: 45 output transformer

Quote:
Originally posted by The-Planet
The Hammond 125ESE and 125E are both good sounding within their modest price range, but have significant limitations in bass.
That's certainly not true in all circumstances. It has a primary inductance of 10.5H at 80mA - so it will be significantly better at half that current, or lower. I would bet a 45 would be less than 2dB down at 20Hz.
I've used them with a 71-A that has an Rp of 1170 ohms, and I can tell you that the bass is not lacking in any way.
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Old 31st March 2003, 10:12 PM   #13
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hi joel,

thanks for your opinion, I will try your advise.

thanks

Thomas
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Old 1st April 2003, 12:55 AM   #14
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Default 125E/ESE

Click the image to open in full size.


Don't get me wrong, the 125E and 125ESE are surprisingly good given their modest cost. I listen to a 6EM7 amp which uses the 125ESE every day in my office.

I've built the simple 45 design referenced here. I've also built a version of Gordon Rankin's "Bugle 45". I spent many weeks living with the Bugle 45 circuit on a breadboard before I committed to a final design. I had a good selection of output transformers on hand to audition. I listened to Tango U808, Hammond 125E, Hammond 125ESE, Hammond 1628SE, Electraprint BE5KB and others. Speakers were Altec A7's.

With a 46 at 22ma or 45 at 36ma there really is something missing on the Hammond 125ESE's lower end. IMHO, in a direct comparison with better iron it was quite audible.
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Old 1st April 2003, 12:28 PM   #15
Joel is offline Joel  United States
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Default Re: 125E/ESE

Quote:
Originally posted by The-Planet
With a 46 at 22ma or 45 at 36ma there really is something missing on the Hammond 125ESE's lower end. IMHO, in a direct comparison with better iron it was quite audible.
TP,

I don't doubt you think you hear a difference - but that doesn't do us much good, does it? Do you have any measurements? They would be most helpful.

Joel
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Old 1st April 2003, 02:48 PM   #16
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Default 45's --> transformer selection

The audible differences were not subtle. I was a bit surprised, but that's what I found.

As measurements go I'm sure a LM3886 would test far better than a 45 amp. I'd still rather have the 45.

That's the joy of this silly hobby
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Old 1st April 2003, 05:55 PM   #17
Joel is offline Joel  United States
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I meant in the same amp. If you're talking about them being in two different circuits, then it's not a valid comparison.

A double-blind would be good too...

Sorry, I just don't buy that a dB or two difference at 20Hz is even noticable.

Joel
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Old 1st April 2003, 06:46 PM   #18
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Default 45 Transformers...

Joel -

I did try all of the transformers in the identical circuit. I had the amp on a breadboard with a heathkit regulated power supply, lots of audiophool grade wire clips and careful parts layout for a long time and went bach and forth between output transformers. Several friends participated in the listening as well.

Ok, so it wasn't completely blind - but I had no vested interest in the outcome. I also can't explain my impressions based on any "science".

In any case, we've probably beat this to a respectable pulp. Some time if you find yourself in New England give a yell. I'd be happy to repeat the "experiment" over a few beers.

On another note, what does your 71A circuit look like?
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Old 1st April 2003, 06:53 PM   #19
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Joel

If i'm not mistaken you tried some better caps and liked them. Did you measure any improvements that correlated with the better sound? Is it so unreasonable to expect that better iron also sounds better? Or do you honestly think that there is no difference at all between different cores, different winding geometries and different insulation materials? Lots of gullible audiophiles falling victim to the 'TANGO CONSPIRACY' ? I also doubt that a db or two is important but that's not where the real difference is.

cheers

peter
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Old 1st April 2003, 06:54 PM   #20
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Default OPT.

Hi,

Quote:
Sorry, I just don't buy that a dB or two difference at 20Hz is even noticable.
There's more to an OPT than just the frequency response last time I looked.

And FWIW, I don't want one that's a few dB down at 20KHz already...even more importantly, I don't want one that's down a few dB at 20Hz.

Maybe not everyone discerns a difference but I do nonetheless.

Cheers,
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