thanks to all you guys for understanding .your help means the world to me.
i cut my sheet of 1/8 aluminum today in 12 x 16 size now not sure which alighnment i side with, at first i was for kt88 in the front but now the kt88 behind the 12at7/ 12bh7 tubes.
[image removed]
or this
[image removed]
i cut my sheet of 1/8 aluminum today in 12 x 16 size now not sure which alighnment i side with, at first i was for kt88 in the front but now the kt88 behind the 12at7/ 12bh7 tubes.
[image removed]
or this
[image removed]
You might also consider a layout with the long dimension as the front of the amp. Toroid would go on (say) the left side, output transformer on the right side, power tubes in front of the output transformer, small signal tubes in front of that--thus all audio circuit components on the right side, power supply on the left side.
The nice thing about this layout is that there is a shorter distance from back to front of amp. Useful (maybe) if you want to put the input jacks on the back of the amp out of eyesight. Thus it might be more optimal for shorter path runs.
The nice thing about this layout is that there is a shorter distance from back to front of amp. Useful (maybe) if you want to put the input jacks on the back of the amp out of eyesight. Thus it might be more optimal for shorter path runs.
thank you kward
well you may not believe it but set out like i have it is the shortest path for heater wire.
i read a paper on modern tube psu design where it states that heater supply is the highest current amps in the chassis and as a result causes some magnetic field effect so should be kept as short as possible to stop hum.
also says that it should go to power tubes first then to the signal tubes
so keeping this in mind the way i have it in the picture with kt88 at the back position is aprox 11 " set out the way you suggested is aprox 13".
and i dislike square or wider then long look just for pleasing view
also dislike rectifier tubes and filter caps on top , they are distracting.
if you look at where the toroid is on the aluminum , the iec connecter will be on the back under the toroid , the rca in and binding post out will be on the top , both on the right of the top toward the back.
see the picture back on page 5 of the stands , amps , power cord. layout the way i mentioned above will suit this setup great . the box the power cable plugs into is a power conditioner i built, 2000 va toroid 60-0-60 regulated emi/rfi filtered netting 120v steady. power cords are furutec PowerGuard 48 and the stands the amps are on i made 14" wide so tube tube amps will fit on these as well
well you may not believe it but set out like i have it is the shortest path for heater wire.
i read a paper on modern tube psu design where it states that heater supply is the highest current amps in the chassis and as a result causes some magnetic field effect so should be kept as short as possible to stop hum.
also says that it should go to power tubes first then to the signal tubes
so keeping this in mind the way i have it in the picture with kt88 at the back position is aprox 11 " set out the way you suggested is aprox 13".
and i dislike square or wider then long look just for pleasing view
also dislike rectifier tubes and filter caps on top , they are distracting.
if you look at where the toroid is on the aluminum , the iec connecter will be on the back under the toroid , the rca in and binding post out will be on the top , both on the right of the top toward the back.
see the picture back on page 5 of the stands , amps , power cord. layout the way i mentioned above will suit this setup great . the box the power cable plugs into is a power conditioner i built, 2000 va toroid 60-0-60 regulated emi/rfi filtered netting 120v steady. power cords are furutec PowerGuard 48 and the stands the amps are on i made 14" wide so tube tube amps will fit on these as well
Last edited:
I take all that with lots of salt. Just look online at pictures of the Soldano SLO 100 guitar amp. It has a truly ridiculous amount of gain and uses very elegant looking parallel rods for its heater connections, and does not suffer from hum. I think sometimes we get over-concerned with taking theory to the nth degree.
Sent from my phone with Tapatalk. Please excuse any typpos.
Sent from my phone with Tapatalk. Please excuse any typpos.
Thanks guys very much
Twisting the wires with a cordless drill looks cool.
Remember that I have no idea what is right. Wires next to a grounded chassis might be a problem.
I was planning only the top aluminum with the bottom frame in walnut.
Now having said that is it better to do the whole chassis in metal and just skin the walnut over it?
Twisting the wires with a cordless drill looks cool.
Remember that I have no idea what is right. Wires next to a grounded chassis might be a problem.
I was planning only the top aluminum with the bottom frame in walnut.
Now having said that is it better to do the whole chassis in metal and just skin the walnut over it?
For OPT's I think you would be much better off sonically with the Dynaco Mark III output transformers for 2 tubes per channel (Triode Electronics exact clones or good used ones) as they have more interleaving and the Pilitrons would be better still for of course more $. For 4 output tubes per channel Bob Latino of tubes4hifi will sell just the output trans. Plus you can get them more quickly then Edcor!
Last edited:
100% correct. The safety ground wire of the power cable has a ring terminal on its end. That ring goes a bolt, washer, lock washer, and nut assembly. Nothing else goes on that mechanical arrangement. The industry term is bonding.
It important to separate chassis (safety) ground from signal ground, both conceptually and physically. The ideal signal ground is a single point. Two good real world implementations of a single point ground (SPG) are star and bus. The SPG is connected to the chassis at but 1 place, frequently close to the safety ground bond. Arrange connections to the signal ground so that high current paths are closest to the chassis connection. Eliminating mini ground loops is the rationale behind that methodology. Correct grounding results in hum free operation.
What's described above uses the chassis as a shield, not a signal carrying conductor. The method is very well tried and true.
Absolutely tight.
Star ground works when the "star" is the point with minimal dynamic resistances in respect to powering voltages, and all strong currents are closed there, no one wire carries both strong and input currents, like wires from the rectifier must go to the first filter cap, and to the first filter cap only. No other "ground" wire should be connected to the re3ctifier ground; that's how you can forget about "sound" of vacuum and fast recovery diodes.
Just remember that any wires, even the thickest ones, have resistance and inductance, and currents cause voltage drops on them.
If recording consoles were soldered like many boutique tube amps are, you would hear nothing behind hum and whistles.
thank you all for the great pointers , it helps more then you know.
tonight i sawed up some walnut in 1/4 " thick peices . these will frame the chassis .... maybe.
as normal after i cut them i started thnking maybe all steel painted black and clearcoated with auto show gloss clear.
after all i am planning to paint the edcor covers anyway so the more it crosses my mind i'm starting to lean that way. every bit of it will blend.
tonight i sawed up some walnut in 1/4 " thick peices . these will frame the chassis .... maybe.
as normal after i cut them i started thnking maybe all steel painted black and clearcoated with auto show gloss clear.
after all i am planning to paint the edcor covers anyway so the more it crosses my mind i'm starting to lean that way. every bit of it will blend.
IIRC, the Edcor end bells are powder coated. Perhaps sand blasting, to give the surface some "tooth", before primer is applied is in order. I have my doubts about paint sticking to the fused resin, without some preparation.
Both steel and aluminum have virtues and shortcomings. Given steel's interaction with the transformers and chokes, I recommend you use aluminum.
Both steel and aluminum have virtues and shortcomings. Given steel's interaction with the transformers and chokes, I recommend you use aluminum.
Last edited:
guys now winter is here and all out door projects stop , i am back at the amp build.
received the output trannys last june.
so just as a refresher, building mono blocks opus 5.0 ultra pp
i have all but the chokes.
i have antek 3t325 power toroids and while the design calls for a little more voltage
will the 325-0-325 just mean a little less wattage?
received the output trannys last june.
so just as a refresher, building mono blocks opus 5.0 ultra pp
i have all but the chokes.
i have antek 3t325 power toroids and while the design calls for a little more voltage
will the 325-0-325 just mean a little less wattage?
thanks
designer of the opus has listed 750 volts so the toroid will be 650 right?
325-0-325
eli had stated in a email to me a type of bump up transformer to connect in line to get it up to 750. i had a computer failure this summer and lost some data.
i think his email with a link to that device is lost.
so this is why i was wondering what the lower voltage will do.
designer of the opus has listed 750 volts so the toroid will be 650 right?
325-0-325
eli had stated in a email to me a type of bump up transformer to connect in line to get it up to 750. i had a computer failure this summer and lost some data.
i think his email with a link to that device is lost.
so this is why i was wondering what the lower voltage will do.
I see three options that would work:
1. Go with your existing 3T325 and accept the lower power output. You will probably need to adjust the bias voltage on the output stage to compensate for the lower plate voltage.
2. Purchase a new power transformer that more closely matches the specs of the original design. For example the 4T360 or 4T400. This would give you a solid 60 or 70 watts output (respectively).
3. Purchase a smaller second toroid, such as the Antek 0540, and connect the secondaries in series additive phase. Combined, this would give you 325V + 40V = 365VAC secondary. In this case you would need to use the full wave bridge rectifier approach, rather than the full wave center tap approach used on the original amp.
Personally, I'd go for either option 1 or 2.
1. Go with your existing 3T325 and accept the lower power output. You will probably need to adjust the bias voltage on the output stage to compensate for the lower plate voltage.
2. Purchase a new power transformer that more closely matches the specs of the original design. For example the 4T360 or 4T400. This would give you a solid 60 or 70 watts output (respectively).
3. Purchase a smaller second toroid, such as the Antek 0540, and connect the secondaries in series additive phase. Combined, this would give you 325V + 40V = 365VAC secondary. In this case you would need to use the full wave bridge rectifier approach, rather than the full wave center tap approach used on the original amp.
Personally, I'd go for either option 1 or 2.
Last edited:
thanks kward for your ideas
at first i was after the most power i could get. this was before i new anything about tube power.
my only referance was a rocket 88 that was rated at 40w / 20w triode.
my complaint was it was not any where enough power. it was set to triode and only 20 watts . i never new the differance and never tried it in pp so i sold it for being a dummy.i felt bad months after doing this when i learned my error.
having said this with a little more understanding, anything 40 or 50 true watts will be great.
so i think your advice for option 2 will be just what i need
at first i was after the most power i could get. this was before i new anything about tube power.
my only referance was a rocket 88 that was rated at 40w / 20w triode.
my complaint was it was not any where enough power. it was set to triode and only 20 watts . i never new the differance and never tried it in pp so i sold it for being a dummy.i felt bad months after doing this when i learned my error.
having said this with a little more understanding, anything 40 or 50 true watts will be great.
so i think your advice for option 2 will be just what i need
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.