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Hammond/Hoffman xfmr...

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1/11/2000 11:20 PM
Ryan S	Hammond/Hoffman xfmr... I was wondering if anyone here has used one of the Hoffman output transformers and how they compare to a hammond (I know they go down to a 2 ohm load which is what got my attention). Also, anyone know were I can get the best deal on a the standard hammond 60w OT (model 1605N)? Thanks in advance! -Ryan

1/11/2000 11:49 PM
Daver	Ryan S., I've used Hoffman 50W and 100W output trannies and liked them both. They seem to be of good quality and Doug Hoffman is knowledgeable and helpful. Never used the Hammonds so I can't compare them for you. Hope this helps. Daver

1/12/2000 8:10 AM

What are you using the Hammond 1650N for?
The 1650N can handle 120 watts of real guitar signal.
If you are building a 100 watt amp, it's OK, but don't use it in a 40-50 watt amp or you'll probably be dissapointed.
Fine for a 50 watt bass amp though.
A 1645, if you can find any, is real good.
There are so many good sounding, over the counter, trannies out now, you should be able to find something cheaper that will work great.
Bruce

1/12/2000 3:02 PM
Ryan S	Bruce, Hammond lists the 1650N at 60 watts, the going rate for a new one is only $68 at most places. I think you were thinking of the 1650T which is 120 watts. As far as over the counter, all the places 'round me only retail hammond and the standard variety of fender/marshall replacements which tend to me be more expensive. Later, -Ryan

1/12/2000 5:43 PM

Hammond/Hoffman/Others

Ryan, I use a Hoffman OT (100W) in one of my amps, and two Hoffman PT (100W) in two of my amps. This is a summary of my experiences with them: the OT sounds, very very nice, and the PTs deliver voltages as per their spec. Having said that, and please don't interpret this as a disrespectful statement, Hoffman's prices are significantly higher than others, and the wormanship on the trannies is too much on the "Q&D" side for my taste.

I have also used "generic" transformers (both PT and OT) from New Sensor and Magic Parts. What can I say about them? They are more affordable than Hoffmans, they soundvery good (as the Hoffman OT does), and the wormanship is far superior IMHO - and everyone else's who gets a chance to look at the two of them side by side. Bending a mounting tab on a Hoffman transformer is as easy as ABC, and it pisses the heck out of me that ALL of my orders resulted in trannies that got mangled during shipping. Some so bad I had to request replacement covers; in all fairness, Doug had no problems whatsoeverwith sending me the replacment covers, so customer support is not a complaint of mine.

Since I had to replace the covers as explained above, I had a chance to look at the insides of the 100W PT. It looks like it was made in a bit of a hurry, with paper tape and a case grounding arrangement that's quite crude. Also, the screws in these trannies go right through the laminates. Other trannies, like the MP Marshall OT, are routed so thatthere is no way a screw (the ones that hold the case in place) can touch the laminates at any time.

Again, the Hoffman trannies work as advertised and sound really good. So do the others I mentioned, at about 20-30% lower prices and more rugged construction.

Gil

1/12/2000 7:59 PM

Re: Hammond/Hoffman xfmr...

ryan, i believe that bruce was referring to the effect of limited bandwidth on the acceptable power transmission through a transformer. IOW, if you limit the range of frequencies which must be passed, you can safely transform MUCH more power than is rated.

hammond is famous for rating their opt's at full bandwidth, which is usually (for them anyways) 30Hz-30kHz. this is a much wider range than is normally required for guitar frequencies. as a result, a 30W hammond tranny is about the same physical size as a marshall 50W tranny.

if you halve the bandwidth, you can just about double the power transmission before the core saturates. that means the lowly hammond unit rated 60W 30-30k will pass 120W 60-15k, which is a much more reasonable range of guitar frequency energy.

ken

1/13/2000 8:16 AM
Bruce	Thanks Ken, that's exactly what I ment. Even the 1650F will run right up there with any over the counter 50 watt OT for two EL34s in a guitar amp. Ask anyone who's been to my place and seen my transformer collection! I've tried a few... Bruce

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