Hammond type m-b 5u4 organ tube amp conversion to hifi

  • Thread starter Musiclistenerdiyfun
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M

Musiclistenerdiyfun

Audiophyte
Any help would be greatly appreciated. Im not very comfortable with the necessary modifications needed to make this organ amp into a home audio amp, or what i think is referred to as a hifi amp. I'll be using it to hopefully experience and enjoy the qualities associated with vacuum tube amplifiers.
 
M

Musiclistenerdiyfun

Audiophyte
It is actually a hammond ao-29-1d from a hammond type m organ.
 
highfigh

highfigh

Seriously, I have no life.
Any help would be greatly appreciated. Im not very comfortable with the necessary modifications needed to make this organ amp into a home audio amp, or what i think is referred to as a hifi amp. I'll be using it to hopefully experience and enjoy the qualities associated with vacuum tube amplifiers.
Not sure it will be good for HiFi, but people are using them as guitar amps, after a few simple modifications. Wide frequency range, low distortion and correct output transformer for the speaker load are important.

I would recommend doing a google search for the exact model number and add 'as HiFi amplifier'.

It will need some mods and if you're not comfortable with doing this, have someone else do it- tube amps use high DC voltage and if someone touches the metal chassis (or anything that's grounded), it can be lethal. DC is more dangerous than AC, but both are dangerous.
 
KEW

KEW

Audioholic Overlord
I'll be using it to hopefully experience and enjoy the qualities associated with vacuum tube amplifiers.
I think the general attribute of a tube amp is adding (not unpleasant) harmonic "coloration" (distortion) of the sound. Often popular for filling out the sound of a guitar. Not unlike the way my voice sounds fuller and richer in the shower.
This can be enjoyable for a very sparse recording or a solo, but if you listen to music that gets busy with several parts, it can start to get crowded and blurred with the extra "fill" from the tube amp.
Of course there are lots of tube amps with different degrees of this and I believe some can be quite clean.
I have no idea where the Hammond would sit within this span.
 
highfigh

highfigh

Seriously, I have no life.
I think the general attribute of a tube amp is adding (not unpleasant) harmonic "coloration" (distortion) of the sound. Often popular for filling out the sound of a guitar. Not unlike the way my voice sounds fuller and richer in the shower.
This can be enjoyable for a very sparse recording or a solo, but if you listen to music that gets busy with several parts, it can start to get crowded and blurred with the extra "fill" from the tube amp.
Of course there are lots of tube amps with different degrees of this and I believe some can be quite clean.
I have no idea where the Hammond would sit within this span.
There are many types of designs for tube amps and changes can be made in any stage. A tube amp can handle any type of music and it's not "fill". The distortion may be higher, but how the distortion is analyzed makes a big difference. Where is the distortion? If it's in the lower-order harmonics, it's not as damaging to the sound as higher-order harmonics. The output transformer is a very important component WRT frequency response bandwidth and overall sound quality, but an amplifier designed for musical instruments doesn't need to be as squeaky-clean as a HiFi amplifier.

As far as "filling out the sound of a guitar"- tube manufacturing dropped off severely in the late-'60s/early-'70s in the US and the amplifier manufacturers replaced them with transistors. They were pushed into using transistors by transistor manufacturers, who told them they were cheaper, better and sounded better. That may be true for a stereo system, but for guitar, tubes are still king and I would like to have been at the curb or at local dumps to catch some of the equipment that was tossed when they stopped working or were seen as "inferior" at the time- I could have retired long ago. I was lucky enough to snag a Fender Tweed Bassman in the late-'70s for the going price at the time, but most people never realized how much demand for this and other models would increase after the hair and metal bands had their reign of terror. Those guys want high gain amplifiers with high power and they're really a 'one trick pony'. Also, nobody wants to move one if it uses tubes.

If you haven't, check out some of the higher-powered, high end tube stereo amplifiers at a local audio store- when it's a good one, tubes vs transistors is forgotten.
 

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