Greetings to all
I am seeking preferences from the membership on my heater wiring on a new (first for me guitar amp) scratch build. I do have over 40 years in electronics repair, scratch builds of other equipment and much related work, since age 12.
My main question is:
After much reading and searching of other individual's results on heater wiring orientation here, and on the web - I am inclined to bring my heater wires "down" to each socket with the wires in between "floating" above the rest of the circuitry.
1) Yes, they will be twisted right up to the each socket.
2) I will be maintaining polarity throughout.
3) The output tube heaters will branch off of a tie strip, near the power transformer and these higher current heaters will be away from the preamps. The other heater wires will "end" at the first preamp, and will have the least amount of current flow at that location.
4) The 6.3 V AC winding is center tapped and will be grounded.
5) The chassis is .080 aluminum, not steel, I do not feel I will gain much by longer wires running to the edges of the chassis. And I do have 2 inches of depth to allow elevation of the twisted pairs away from the point to point circuitry.
The amp is loosely related to a Marshall type circuit. It is all tube, SS bridge rectifier and will be stereo. Each channel is 3) ECC83 and P-P EL34 - about 50 watts each side.
I value the opinions on this forum and look forward to input from all of you.
Thank you much
Deric
I am seeking preferences from the membership on my heater wiring on a new (first for me guitar amp) scratch build. I do have over 40 years in electronics repair, scratch builds of other equipment and much related work, since age 12.
My main question is:
After much reading and searching of other individual's results on heater wiring orientation here, and on the web - I am inclined to bring my heater wires "down" to each socket with the wires in between "floating" above the rest of the circuitry.
1) Yes, they will be twisted right up to the each socket.
2) I will be maintaining polarity throughout.
3) The output tube heaters will branch off of a tie strip, near the power transformer and these higher current heaters will be away from the preamps. The other heater wires will "end" at the first preamp, and will have the least amount of current flow at that location.
4) The 6.3 V AC winding is center tapped and will be grounded.
5) The chassis is .080 aluminum, not steel, I do not feel I will gain much by longer wires running to the edges of the chassis. And I do have 2 inches of depth to allow elevation of the twisted pairs away from the point to point circuitry.
The amp is loosely related to a Marshall type circuit. It is all tube, SS bridge rectifier and will be stereo. Each channel is 3) ECC83 and P-P EL34 - about 50 watts each side.
I value the opinions on this forum and look forward to input from all of you.
Thank you much
Deric
This is fine. The main issue is to keep as much distance between the (tightly twisted) heater wiring and the rest of the circuitry as possible.
I use this approach in tube power amps as well. Usually I arrange the heater wiring to be close to the bottom plate of the amplifier,
going vertically right up to the tube sockets.
Thank you Rayma
I was pretty much convinced to do the method I described and you reiterated basically the same thoughts as mine.
I thought I would see if anyone had good results with another way of routing, but I will proceed to get the heater wiring installed soon.
It has been since last late Winter getting started with the bare chassis. Most everything is mounted and ready to install the passive small components.
My layout does keep the preamps up front near the input jacks and pots and allows fairly short connections.
I also will have several nodes of star ground running to a common point and will keep the main power supply filters current out of the preamp commons.
Spending the time to get a workable layout pays off in the long run.
I have used my current Marshall amp since getting on stage in 1980. It has held up well with periodic maintenance and output tube replacements as needed. I cannot complain - have done over 1000 shows and never had it let me down.
Once this project is completed, I will try to get a few photos to share with the forum. It will be in a rack style case and variable speed 12 volt fans to exit hot air in the rear.
Thank you
Deric
I was pretty much convinced to do the method I described and you reiterated basically the same thoughts as mine.
I thought I would see if anyone had good results with another way of routing, but I will proceed to get the heater wiring installed soon.
It has been since last late Winter getting started with the bare chassis. Most everything is mounted and ready to install the passive small components.
My layout does keep the preamps up front near the input jacks and pots and allows fairly short connections.
I also will have several nodes of star ground running to a common point and will keep the main power supply filters current out of the preamp commons.
Spending the time to get a workable layout pays off in the long run.
I have used my current Marshall amp since getting on stage in 1980. It has held up well with periodic maintenance and output tube replacements as needed. I cannot complain - have done over 1000 shows and never had it let me down.
Once this project is completed, I will try to get a few photos to share with the forum. It will be in a rack style case and variable speed 12 volt fans to exit hot air in the rear.
Thank you
Deric
The general rule is that AC heater wiring should be the first to go in right next to the chassis. This is because it keeps it as far as possible away from signals, it gains a little electrostatic screening from the chassis, and it is the least likely thing to need modification during debugging.
Thank you for your input DF96.
I had read the thread on heater wiring orientation on the forums here. And much other info on the web from various sites. As mentioned I have done a significant amount of design and build over the decades for not only myself but also customers and employers who had me create a wide variety of custom electronic solutions required.
My inquiry on these DIY forums was to seek input, which I am grateful to receive, regarding the heater wiring results from others to compare to general information on various forums and other websites. My other vacuum tube amp construction projects were not of the very high gain variety.
I still have a working stereo tube amp from my high school senior project that was a line level input rather than receiving the output from a guitar pick up. It works well to this day.
As far as keeping the heater wiring as far as possible from signal wiring, I had said that my preamp sockets, the input jacks and potentiometers are all located along the front of the chassis and very proximate to each other.
If I run the twisted pairs along the pots and jacks, next to the chassis corners, it puts the heater wiring right next to the pots and jacks. I had more or less decided to run the heater wiring 2 inches below the sockets and come up to the sockets right at each socket.
This allows the maximum distance away from especially the low level signal circuit areas. I do have a bottom plate that the heater wiring will rest against after completion of the build.
It will be point to point on the signal wiring and all will be quite short in length considering the proximity of the jacks, sockets and potentiometers to each other.
Again thank you
Deric
It is worth considering 'elevating' the reference DC level for the centre tap 30V or 40V or so above ground.
There is an explanation of how this can reduce hum on Merlin's web-site:
The Valve Wizard
Some good stuff here: http://www.diyaudio.com/forums/tubes-valves/211731-heater-wiring-good-bad-ugly.html
Hi Malcolm
Yes, I was aware of the possibility of elevating the potential of the heaters via the method you describe. I have been shooting for as simple as possible, within reason. It will be very easy to implement this even after I do initial tests, if I feel it will help.
Thank you sir
Thank you moderator sir
I did read that thread before asking fellow members on their personal experiences in this matter. I agree that it is a must read and for all to digest the information within that extended thread.
Appreciate your input and I will say you do a good job here sir.
Deric
A brief update:
Last night, I did complete all of the heater wiring. I did orient the twisted pairs that are installed to run along the bottom plate - turn, and rise up to the sockets, maintaining twist and relative polarity.
As I look at it - this still puts the majority of the twisted pair lengths right next to the aluminum bottom cover plate (2 inch deep chassis), it minimizes the nearby components exposure to the heater wiring electrical fields, and provides the maximum distance away from the majority of the future installation of the remaining components.
I much appreciate the collection of input and advice from those who responded to my inquiry.
Thank you all.
It will be a bit of time to gradually finish the build. I will share results as it becomes available.
Deric
Last night, I did complete all of the heater wiring. I did orient the twisted pairs that are installed to run along the bottom plate - turn, and rise up to the sockets, maintaining twist and relative polarity.
As I look at it - this still puts the majority of the twisted pair lengths right next to the aluminum bottom cover plate (2 inch deep chassis), it minimizes the nearby components exposure to the heater wiring electrical fields, and provides the maximum distance away from the majority of the future installation of the remaining components.
I much appreciate the collection of input and advice from those who responded to my inquiry.
Thank you all.
It will be a bit of time to gradually finish the build. I will share results as it becomes available.
Deric
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