Hi there, thanks for coming by.
While I can probably figure this out myself, it would be nice to hear from those that have specifically done this.
I'm rounding up parts for a stereo tube amp build (60W per side, KT88's, 2 GZ34's and maybe 4 6SN7's).
My question is, are there any guidelines you would adhere to regarding proximity of tubes-to-tubes, transformers-transformers, and tubes-to-transformers. I'm sure I have not much to worry about as this is being build upon a 19" rackmount chassis and I can make the depth anything I want. I was thinking around 12 inches. That's a lot of room to spread things out. It would still be nice to hear from those though, that have found through experiment or mistakes, what the biggest perpetrators of unwanted electro-magnetic cross interferences have been so I could monopolize on those findings. Why not? I understand the positioning of PT and OT, angles and proximity but, I really don't know anything about GZ34 rectifiers and their risk of causing hum or noise in other elements/components. I would instinctually keep anything "input/preamp" away from anything "power related" or higher current output related but would just like to gather as much as possible before committing everything and drilling lots of holes,
This amp will be a Williamson type of amp, probably with a few things to increase stability and/or volume - that's to be seen, though.
Thank you,
Best,
Phil D.
While I can probably figure this out myself, it would be nice to hear from those that have specifically done this.
I'm rounding up parts for a stereo tube amp build (60W per side, KT88's, 2 GZ34's and maybe 4 6SN7's).
My question is, are there any guidelines you would adhere to regarding proximity of tubes-to-tubes, transformers-transformers, and tubes-to-transformers. I'm sure I have not much to worry about as this is being build upon a 19" rackmount chassis and I can make the depth anything I want. I was thinking around 12 inches. That's a lot of room to spread things out. It would still be nice to hear from those though, that have found through experiment or mistakes, what the biggest perpetrators of unwanted electro-magnetic cross interferences have been so I could monopolize on those findings. Why not? I understand the positioning of PT and OT, angles and proximity but, I really don't know anything about GZ34 rectifiers and their risk of causing hum or noise in other elements/components. I would instinctually keep anything "input/preamp" away from anything "power related" or higher current output related but would just like to gather as much as possible before committing everything and drilling lots of holes,
This amp will be a Williamson type of amp, probably with a few things to increase stability and/or volume - that's to be seen, though.
Thank you,
Best,
Phil D.
Heat is the real enemy. Tubes 1/4” from power or output transformers is not so great. On the other hand, having the leads too long on everything is also not good. I would look at designs by well known companies and highly regarded amps from them, and base things off of that to start with. Keep heat sensitive components away from heat producing components, though.
Thanks anchorman,
So far I've had good results with quiet and behaving amps, but where this one will be a 2 channel amp with 2 rectifier tubes, 4 KT88's and 4 or so 6SN7's, I wanted to make sure I am aware of potential pitfalls. As mentioned, there should be plenty of room for things to spread apart and come up with good location/spread-out decisions. I was actually concerned mostly with the GZ34's that will be included. I think of those as receiving the big differential AC and had to wonder what they might be the enemy of in terms of electromagnetic infiltration. I know the current there isn't as big as say, the heater lines but, the rect tubes are just something I haven't heard discussed in terms of EMI. I know they get pretty hot so, plenty of breathing room for those.
Thanks you,
Phil D,
So far I've had good results with quiet and behaving amps, but where this one will be a 2 channel amp with 2 rectifier tubes, 4 KT88's and 4 or so 6SN7's, I wanted to make sure I am aware of potential pitfalls. As mentioned, there should be plenty of room for things to spread apart and come up with good location/spread-out decisions. I was actually concerned mostly with the GZ34's that will be included. I think of those as receiving the big differential AC and had to wonder what they might be the enemy of in terms of electromagnetic infiltration. I know the current there isn't as big as say, the heater lines but, the rect tubes are just something I haven't heard discussed in terms of EMI. I know they get pretty hot so, plenty of breathing room for those.
Thanks you,
Phil D,
A lot, actually it all, depends on if your transformers are potted or not. If you already have a tube amplifier and your transformers are not potted then hold e.g. a choke close to a working amplifier and hook up a mV meter to the leads of the choke. Then move the choke around and make notes on where you measure the least and the highest amounts of amplitude.
If having high level of amplification on the same chassis, e.g. a preamp with tone control included then have the pre-amp tubes as far away as possbile from the mains transformer.
If not using global negative feedback (or ony in minimum amounts) and are using "normal, unshielded" transformers be aware that beam power tubes are sensitive to magnetic fields. I much prefer to have unshielded output transformers horizontal (as opposed to vertical), the choke vertical and the power transformer flat (laminations parallel to the chassis - I just buy new bell covers).
If using potted output transformers then you can place these between unshielded chokes, mains transformers and the amplifier tubes. Rectifier tubes can have a strong magnetic field too so keep those away from the input.
No need to get too worried about it, just be sensible.
Take a look at the KT66 datasheet (I think GEC) that mentions minimum distance between tubes.
If having high level of amplification on the same chassis, e.g. a preamp with tone control included then have the pre-amp tubes as far away as possbile from the mains transformer.
If not using global negative feedback (or ony in minimum amounts) and are using "normal, unshielded" transformers be aware that beam power tubes are sensitive to magnetic fields. I much prefer to have unshielded output transformers horizontal (as opposed to vertical), the choke vertical and the power transformer flat (laminations parallel to the chassis - I just buy new bell covers).
If using potted output transformers then you can place these between unshielded chokes, mains transformers and the amplifier tubes. Rectifier tubes can have a strong magnetic field too so keep those away from the input.
No need to get too worried about it, just be sensible.
Take a look at the KT66 datasheet (I think GEC) that mentions minimum distance between tubes.