Transformer brand question

[keaster]

Just looking through some amp circuits for something cheap to build and came across this


I was going through the parts to get an idea of how much it would cost to build and was shocked at the price of the Hammond transformers. I've used Edcor before and found something that I think would be a close match.

Hammond 1608A $117
Edcor GXPP10-8-8K $26.10

So why so much difference in price?

[GloBug]

The Edcor is 1.75 lbs.
The Hammond is 2.5lbs.

The Hammond is ~%30 bigger.

Generally the bigger the iron, the better the bass.

Lot's have folks have been using Edcore because they are cheaper though, they seem to be happy.

You can save a little bit with the Edcores but generally speaking you get what you pay for.

Get the Edcores, upgrade if you want later or save the Hammond purchase for another project.

[scott17]

You will get a better frequency response from the Hammond unit in comparing the two units you mention. A closer and better match for the Hammond unit is the Edcor CXPP25-MS-8K. Superior frequency response and still less expensive.

EDCOR Electronics Corporation. CXPP25-MS-8K

[kmaier]

Well, agree on iron opinions so far.... better iron costs more, period, and you should be careful as this is a budget design (low parts count and cheap) with feedback. In my view, why bother (I built the original referenced Dyna circuit from the original (Dyna) brochure over 45 years ago, it's not that great), you can add one tube and do so much better (for a stereo amplifier).

Regards, KM

[scott17]

Originally Posted by scitizen17

You will get a better frequency response from the Hammond unit in comparing the two units you mention. A closer and better match for the Hammond unit is the Edcor CXPP25-MS-8K. Superior frequency response and still less expensive.

EDCOR Electronics Corporation. CXPP25-MS-8K

This Edcor PT would also be a good substitute for the Hammond PT:
EDCOR Electronics Corporation. XPWR172-120/220

[DavesNotHere]

I would do the 25W edcor or even a 50W for more power headroom.

but I would change the coupling caps : .1 to 1 uf and the bypass on the output from 47uf to 330Uf as that will give you better power bandwidth gain at lower frequencies. and the classic designs are set up this way.

[Richard Ellis]

Another observation here............" 0.25 Watt resistors unless otherwise noted".

No, no, use some One-Watt resistors, don't be cheap....someone wanted to cheapen things......Rules of thumb, Over design...don't run it any-where near the limits, overbuild! Besides 0.25 watt resistors can be so small to work with....1W are better.

_________________________________________________R ick............

[keaster]

Now that the topic has turned to the amp circuit....is it any good?

[rmyauck]

This might be more appropriate with close to 25% UL taps.

EDCOR Electronics Corporation. CXPP25-MS-8K/23%

Also look at the Z-565 clones out there say ones from:

Z565-48 17.5(35W) Watt Triode USA Dyna Clone Output Transformer for Dynaco MADE IN USA

If you have the budget.


Broskie's looks like it is a well liked PP design for diy P2P wiring.


Anyone ever made the EL84 P-P circuit referenced on the Tubecad Journal site?

Use Dave Gillespie's EFB mod on it for great sonics.

http://tronola.com/html/dave_s_lab.html

More info at diytube.com under ST-35

For example:

http://www.diytube.com/phpBB2/viewtopic.php?t=4654

Randy

[rmyauck]

George's tubelab simple EL84 PP board is another great way to go and you can get a kit of board parts for it.

Board Availability