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99.141.96.45
I have one of John Hogan's 26/300B amps. Love the sound , but I would like to convert it to a 26/45 if possible. As we know,John has past on, and my question is.... can this amp be converted without compromising it's original sonic beauty,or is converting far more complicated than simply changing the operating points of the tubes ?
I needed to switch around my system and didn't want to mess with John's work so I sold it to build what I needed. If you want a 45, build from scratch. Cheers.
I am glad that John really did something in this field with the last 5 years or so of his life. It is fortunte that some of it landed on fertile ground. I guess John had already acquired the requisite skills before he started building, and then he had the time and interest to really devote to it.Something to be said when a man or person goes into the basement of the house, their own private space, and devotes hundreds upon hundreds of hours alone and involved in something.
John pulled some circuits and ideas off the internet, and started building amps from scratch. He stripped old organ amp chasses out completely, boring needed holes in them and covering others in a way to lay out his tubes and circuits. Then whatever mental or emotional processes take over from there, I don't know but he really became consumed with building.
Not that he neglected any of his responsibilities but at least for one year, the christmas tree was still up in August. John was busy doing something.
It was really just his quirk to utilize what was around him material wise that led to the fortuitious find of the vintage webster opts. John did not realize what he had found. It would have been lost to him.
Some builders have great listening ability music wise but I would not say that John was one of them. But he did have the more important ability, perhaps, to get lost for a long time in what he was doing and in the sounds of it all. It was those hours upon hours lost in the process of what he was doing: the tinkering, the trial and error, the persistence, the devotion, the skill, the loneliness. John knew what to do with himself but not really until he started building amps. But near the end, after whatever it was, 60 amps or so, (he counted a pair of monos as two amps so his estimate was higher), maybe he felt some sort of plateau and started developing a side interest in putting together trains and tracks for his grandson.
I hope what he built provides some shelter from the storm, and it also provides the hours alone lost in it.
That is really what is available in these amps which are chamelon and adaptive: the ability to sustain an interest for hundreds upon humdreds of hours, and the ability to let your mind get lost in the music and the sounds. What is coming out of the amps is exactly what was put in: that private space and world, the inner world.
Edits: 11/05/09 11/05/09 11/05/09 11/06/09
Just a thought about changing your Hogan amp from 300B to 45.
If I remember correctly John used Push-Pull OPT's from Webester PA amps in his builds.
These OPT's have been the topic of lenghty discussion in the past about there quality, sound and in this application.
For what you want to do going from a 300B to a 45, using those Webster OPT's would be a more worthy application than using them with a 300B. By having lessen the possibility of OPT core saturation when running 45's
JMHO!
Have fun!
Willie
Although I am sure it could be done, I would suggest you do not change the amp. I am lucky enough to have a number of John Hogan amps and know a little about his process for building them. I am not talking about technical issues of heater voltages or tube operating points, as I am not knowledgeable enough to comment on these. John’s process for building involved thinking about the circuit design and then tinkering the amp into existence. He would put it together, measure, tinker some more and then listen. Then he would go try a small change and go through the whole process again. Basically, he built his amps by ear. I happen to really like the resulting “Hogan” sound, focused on the midrange with a great combination of richness and detail. Also, I like the fact that his amps are sensitive to tube selection and as a tube roller, this makes them more fun for me. So I suggest you keep the amp as is but do some serious tube rolling to get the sound more to your liking. Between the multiple options for rectifiers, 6SN7’s, 26’s and 300B’s, you should be able to make some noticeable changes in the sound.
Note: I have reread my comment above and want to add to it. First, I wasn’t sure the word “tinkering” was really correct. Then I looked at synonyms as saw “fiddle, toy, mess and play” and thought tinker was just about right. Second, as I was reading, I remembered that at one point I emailed John, asking about the possibility of his making some changes to one of his amps that I had purchased from someone on Audiogon. His reply was, something like, “Yes that could be done, but I would have to change this, and that, and several other things. You know, it would be easier if I just built you a new amp.” So I had him build it. Sadly that is no longer an option, but I am happy to be able to enjoy the unique machines he left behind.
300B. A 45 often uses a 5k, so there is your biggest mismatch I think. Otherwise it is do-able. But I would also suggest keeping this one. And then building or buying a 45 amp.
To infinity and beyond!!!
In many ways, John was an artist. He had his own very distinctive style of amplifier building and you are lucky enough to own one of his creations. Treat it like you would a painting and leave the amplifier as it is.
As a suggestion, look around and purchase a 45 amp either by John or some other builder and then you can switch back and forth as you wish.
ray
Yea John was a special cat. I have yet to delete any of his e-mails from the few years he shared with us all.I will keep the amp as is. I'm interested in a 26/45 Hogan amp you guys !
This is doable. You will probably want to look into direct coupling, as you likely have extra B+ for the 300B. You will also probably be best off rectifying the 5V winding for the 300B's and bumping it down to 2.5v. See other posts for info on DC on the filaments.
It is not that easy by just changing the Operating points although you surely will. You have to change the heater voltages for sure(plus current draw are not the same for the 300B against the 45). You have to account for lower power dissipation of the tube also since I think 45's operate at 10W Pd max.I think changing 2A3 to 45 is much easier than changing 300B to 45's.
Just my thoughts....
DIY, all the time!
Edits: 11/03/09
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