Hammond 270 FX PT Questions

[Ed_Chambley]

I was looking through some parts a friend gave me and low and behold a brand spankin new PT in the box . A Hammond 272FX, VA 146, Primary 115, Hz 60, Secondary 600V C.T. @ 172ma. Fil 1, 5V C.T. @ 3A, Fil 2, 6.3V C.T. @ 5A.  Never used Hammond Transformers before, but I hear they make a good product.  I was planning my next build to be on the lower wattage SE side, but It seems a shame not to put this use, immediately .  Problem is every amp I have built (excluding a JTM-45) has been fixed bias with a center tap and along the lines of Fender amps.  Excluding the OT and chassis, there is enough parts to build pretty much anything.  I know this is a very open ended question, but what type of build would you use it for.  Since I don't have a lower wattage, cathode bias amp I might like to try my hand at building one.  Any one have any suggestions where this PT may work for this type of application.

Thanks,
Ed

[sluckey]

Sounds like a candidate for a couple 6V6s or 5881s. It's a little too hot for most EL84 amps.

[Colas LeGrippa]

Hi, I have built a SE amplifier with a 2204 preamp and a super champ power amp. What a tone, crunchy, stiff, LOUD. I can swap 6V6, KT77, El 84, EL 34 name it. With the power tranny you have, you could go with a SE with dual paralled output tubes with all the benefits of a SE and the tone of a solid rock.

Just my humble opinion..

colas

[stratele52]

Nice Power transformer, hammond is a very good product, I use them very often. this is a powerfull transformer,

Your B+ will be around 425 volts

[sluckey]

I just realized that your title says "270FX" but the message body says "272FX". The 270 is a good choice for EL84 amps. So, which do you have???

[Ed_Chambley]

I just realized that your title says "270FX" but the message body says "272FX". The 270 is a good choice for EL84 amps. So, which do you have???

This time I looked at it.  It is a 270FX, sorry for the confusion.

[sluckey]

Well it's about perfect for a push/pull EL84 amp. Lot's of those to chose from, Doug's Stout, Marshall 18 watt (and variants), November amp from AX84.com, Matchless Lightning, etc, etc.

Here's two amps I built using that PT. Both are EL84 amps, one fixed bias, the other self biased.

http://home.comcast.net/~seluckey/amps/lightning/matchless.htm
http://home.comcast.net/~seluckey/amps/vox/vox.htm

[DummyLoad]

the specs given are for a 272FX. nice transformer. should work well with 2x6L6, or 2xEL34, or 4x6V6. i'd go with SSR.

--DL

edit: missed that ...

It is a 270FX

never mind... 

[Ed_Chambley]

Well it's about perfect for a push/pull EL84 amp. Lot's of those to chose from, Doug's Stout, Marshall 18 watt (and variants), November amp from AX84.com, Matchless Lightning, etc, etc.

Here's two amps I built using that PT. Both are EL84 amps, one fixed bias, the other self biased.

http://home.comcast.net/~seluckey/amps/lightning/matchless.htm
http://home.comcast.net/~seluckey/amps/vox/vox.htm

Thanks for the info.  It seems as you prefer the Vox flip best.  I have played a many Matchless amp and always thought they were very nice sounding, especially the cleans. It is fixed bias?  I do not see a bias pot, did you just use a resistor?  Looking at the layout at Ceritone it seems to cathode bias.  Are those bias probes in your photos just left from something else?  Also, if I remember correctly I read where you installed a VVR in this amp.  Seems like Matchless likes 4 ohm cabinets as well.  It seems like you were not pleased with the build.  What is it you are not liking?  Also, in your opinion what would be the best OT to use for 2, 10's.  I had weber recone some old CTS speakers using the Blue Pup and Silver ten at 40 watts.  They sound great in a 5f4 build I have. I have 2 more I am not currently using. (Side note) I love the 5f4, I have 4 different build versions of this amp. I prefer 2 different voiced speakers in am amp, don't know why.  I guess it is just a quirk of mine.  As you may tell, I am leaning towards your matchless idea, I just want to know what you would do differently as you comments with your photos mention you did not like the way it turned out.

[sluckey]

My Matchless Lightning is self biased (cathode biased), same as the original. It's too hard to dial in the tone in the bedroom. I hate the crossline MV. May be different in a club setting.

The bias test points are actually in use in the Lightning. Refer to the schematic. I originally had a fixed bias November amp built on that chassis. That's why the extra holes on the rear panel. I re-used the bias test points mainly because they were already there. I've never bothered with bias test points for my other self biased amps.

Doug's 18Watt OT would be a great choice. So would a Hammond 1650F. The OT in my Lightning came from an old Fisher mono FM receiver.

Nothing wrong with the Lightning. It's just not a good 'match' for me. (pun intended). All the youtube clips I heard sounded good, but they were also much louder than I'll ever play again. I think the Lightning would be a good small club amp.

[Ed_Chambley]

Thanks for the replies.  It has been very helpful and I am sorry I got the wrong PT number and specs in the beginning..  It seems it may be good for a 18 watt since the Matchless has to be sort of cranked to sound good.  I don't understand that, I think I'll go and check one out.  We have a dealer close by.  Don't need an amp that doesn't sound good till you reach wife screaming volume.