45 SE tube amp OPT

[kmtang]

Hi,

My friend is anxious to build the 45 SE tube amp. We just don't know what OPT is good for this. The Hammond 1628SE OPT is suffering from the frequency at 16kHz for -4 to -5 dB's.

Wondering what other good OPT's you recommend?

Johnny

 

[PRR]

> The Hammond 1628SE OPT is suffering from the frequency at 16kHz for -4 to -5 dB's.

It is rated much better than that. http://www.hammondmfg.com/1627.htm

What makes you think it is the transformer, and not the driver or the test set-up?

 

[audiousername]

It is rated for that, but several measurements appear to show that it has a nasty dip a little past 10kHz.

[IMGDEAD]http://www.sacthailand.com/PIC/TransTestFC-6128SE.jpg[/IMGDEAD]

 

[SHiFTY]

Depends on your budget. If you don't have much to spend, you could try the cheap hammonds (125ESE, FSE, etc). However I found they didn't sound great, ok but not great.

If you have more to spend, the lundahls or one electrons are reputedly good.

And then there's always silver wire magnequest...

As PRR inferred, the driver stage and speakers of the amp will make a huge difference. Go for a proven 45 design, and use efficient speakers.

 

[Sherman]

...The Hammond 1628SE OPT is suffering from the frequency at 16kHz for -4 to -5 dB's.

Wondering what other good OPT's you recommend?

Johnny

I built a pair of monoblocks (not 45s) using James 6123HS OPTs. They can be substituted for the Hammonds and the price was the same. They sound great.

 

[kmtang]

Thank you so much for your inputs.

The Hammond 1627 SE OPT is great but it's impedance is 2.5K that won't match with the 45 tube.

It seems James and One Electrons would be good for consideration.


Johnny

 

[kmtang]

Hammond 1628 OPT

I built a stereo 45 amp with Hammond 1628 OPT. The driver stage I used is a cascade 6J5's which is the designed of Sun Audio.

I measured the frequency response of it and it come up the same as the frequency response curve shown above.


Johnny

 

[rdf]

A long discussion on the 1628SE here:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=50003&highlight=

I also used them and regret James weren't available at the time. Don't know if these issues were addressed in later production runs.