🙁55.4 negative pad to ground
42.8 positive pad to ground
and that would be a negative 12.58 across c18 pads
42.8 positive pad to ground
and that would be a negative 12.58 across c18 pads
What DC voltage do you read on the Hneg and Hplus pads of the PS-14 with the black probe on neg and the red probe on plus?
Perhaps the pads are mis-labeled on the PS-14?
Perhaps the pads are mis-labeled on the PS-14?
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I almost had time to put signal through it, but ran out of time. On the road, will look forward to trying it when I get back.
Chassis design time, for me that actually is the fun part! On projects like that I usually make two or three since the setup time is what costs. It's 10 % more work to make 3 than one.
Chassis design time, for me that actually is the fun part! On projects like that I usually make two or three since the setup time is what costs. It's 10 % more work to make 3 than one.
Thanks for the help from everyone. I was supposed to have all of the materials for the chassis yesterday but it seems Monday is when I will get more serious.
Have it sounding pretty nice. I'm going to pick up some o-rings to put around the tubes hoping it makes them less microphonic.
If I want to keep the signal not grounded to the chassis, is heat shrink tube around the RCA jack which would contact the aluminum part of the chassis an effective solution?
I'm redoing the signal wiring with shielded twisted pair, for now the shield will not be attached to anything but planning on having a tab on the chassis to attach it just to see which is better.
I moved the pot to a cigar box while doing as many things to reduce hum as possible and like the way it declutters so I may keep it that way. Currently using a 100K radio shack pot.
If going with a separate enclosure, is 1.9" internal height enough for any attenuators out there? Also looking for an affordable recommendation on an attenuator- no Goldpoint this year 🙂
I'm considering the Broski stereo attenuator, but it isn't cheap and not so ready to throw money his way after the PS-14 experience.
Have it sounding pretty nice. I'm going to pick up some o-rings to put around the tubes hoping it makes them less microphonic.
If I want to keep the signal not grounded to the chassis, is heat shrink tube around the RCA jack which would contact the aluminum part of the chassis an effective solution?
I'm redoing the signal wiring with shielded twisted pair, for now the shield will not be attached to anything but planning on having a tab on the chassis to attach it just to see which is better.
I moved the pot to a cigar box while doing as many things to reduce hum as possible and like the way it declutters so I may keep it that way. Currently using a 100K radio shack pot.
If going with a separate enclosure, is 1.9" internal height enough for any attenuators out there? Also looking for an affordable recommendation on an attenuator- no Goldpoint this year 🙂
I'm considering the Broski stereo attenuator, but it isn't cheap and not so ready to throw money his way after the PS-14 experience.
I use decent RCA's from mouser that have isolation washers...just oversize the hole in the chassis and you are gtg.
I use alps rk27 from mouser...nice quality and feel...although I have been playing with an eBay pga2311 that I mated to an arduino board so I can use an apple remote with it. Works pretty good. You can pick them up for like $30 if you just wanted to use the standard remote with it.
See thread here
I use alps rk27 from mouser...nice quality and feel...although I have been playing with an eBay pga2311 that I mated to an arduino board so I can use an apple remote with it. Works pretty good. You can pick them up for like $30 if you just wanted to use the standard remote with it.
See thread here
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lost a channel
My local source of aluminum has dull metal shears and doesn't make much of an effort to make square cuts which added a few days of trimming and resizing of panels. Even the 1/4" aluminum base was warped by their shears. I should have returned all of the metal and ordered from out of town. If you are in Austin, avoid Westbrook Metals until they replace the blades. Even then, be sure to bring a square and something to measure to check the cuts before leaving.
the wooden test chassis worked fine but somewhere in tightening up the build
i lost a channel in the final build, and as far as I can tell left is right. i bypassed everything for signal, going straight from source, skipping the coupling capacitor selector and going straight out to the amp. all of the signal wires are off it currently.
i've had to shelve it for a couple of weeks. will be able to get back at it towards the end of the month.
It might be time to order another board, this one has had so many solder, remove, repeats that some of the pads are coming off. There is definitely no room for another reattachment of B+ or heater wires on the power supply board.
not shown in the chassis is a z-shaped mild steel shield which follows the transformer side of the power supply from the front of the chassis, does a 90 degree turn to go in front of the switches in the middle, then another 90 degree turn to the back of the chassis.
the signal wire is mostly the two wire shielded surplus stuff from apex jr, the shields were not attached to the chassis. most likely I will end up attaching at the shield to the chassis next to the (isolated) RCA jacks. the wires which went to the pads on the board made a wicked hum when a finger or metal object came near them - such as alligator clips - but attaching the alligator clip to the chassis canceled the hum.
I took a wicked shock yesterday when one of the signal wires broke loose from the main board, maybe the loose end crossed over something on the main board.
I have an alps pot on the way from mouser.
There is not a properly sized fuse in line, I think there is one that is in the IEC jack at 6A. When I have a better idea of which size to use it will go in the area near the power switch.
The unused orange/brown pair of 6.3VAC will be used for an indicator lamp inside the chassis and the light will be visible though the top. The tall power supply heatsink will protrude through the top by a fraction of an inch and have a mesh dome over it.
Fuzzy photo from a couple of days ago.
My local source of aluminum has dull metal shears and doesn't make much of an effort to make square cuts which added a few days of trimming and resizing of panels. Even the 1/4" aluminum base was warped by their shears. I should have returned all of the metal and ordered from out of town. If you are in Austin, avoid Westbrook Metals until they replace the blades. Even then, be sure to bring a square and something to measure to check the cuts before leaving.
the wooden test chassis worked fine but somewhere in tightening up the build
i lost a channel in the final build, and as far as I can tell left is right. i bypassed everything for signal, going straight from source, skipping the coupling capacitor selector and going straight out to the amp. all of the signal wires are off it currently.
i've had to shelve it for a couple of weeks. will be able to get back at it towards the end of the month.
It might be time to order another board, this one has had so many solder, remove, repeats that some of the pads are coming off. There is definitely no room for another reattachment of B+ or heater wires on the power supply board.
not shown in the chassis is a z-shaped mild steel shield which follows the transformer side of the power supply from the front of the chassis, does a 90 degree turn to go in front of the switches in the middle, then another 90 degree turn to the back of the chassis.
the signal wire is mostly the two wire shielded surplus stuff from apex jr, the shields were not attached to the chassis. most likely I will end up attaching at the shield to the chassis next to the (isolated) RCA jacks. the wires which went to the pads on the board made a wicked hum when a finger or metal object came near them - such as alligator clips - but attaching the alligator clip to the chassis canceled the hum.
I took a wicked shock yesterday when one of the signal wires broke loose from the main board, maybe the loose end crossed over something on the main board.
I have an alps pot on the way from mouser.
There is not a properly sized fuse in line, I think there is one that is in the IEC jack at 6A. When I have a better idea of which size to use it will go in the area near the power switch.
The unused orange/brown pair of 6.3VAC will be used for an indicator lamp inside the chassis and the light will be visible though the top. The tall power supply heatsink will protrude through the top by a fraction of an inch and have a mesh dome over it.
Fuzzy photo from a couple of days ago.
Attachments
how many volts does this output with 6SN7's? with a pair of 6SL7's at V1/2?
i haven't been a big fan of the signal wire choice. It's stiff, springy and if not grounded can add a lot of hum when asked to be in certain positions.
going to move the star ground an inch or so forward.
electro harmonics tubes are much less microphonic than the cheap ones shown in the picture.
i haven't been a big fan of the signal wire choice. It's stiff, springy and if not grounded can add a lot of hum when asked to be in certain positions.
going to move the star ground an inch or so forward.
electro harmonics tubes are much less microphonic than the cheap ones shown in the picture.
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The gain with a 6SL7 in the first position should be about 30. What's your B+? About 250?
It should be plenty enough for an F4. 🙂
Put a 1.0A Slo-blow fuse in and see if that holds during startup.
It should be plenty enough for an F4. 🙂
Put a 1.0A Slo-blow fuse in and see if that holds during startup.
B+ with tube in is about 250, 350 range at power supply without a load.
his spec sheet suggests 300 for 6SL7, if I remember right this can be changed with a resistor that isn't buried too deep on the power supply board.
his spec sheet suggests 300 for 6SL7, if I remember right this can be changed with a resistor that isn't buried too deep on the power supply board.
Should be the big blue one on the side of the PSU near the transformer. Make it smaller (less ohms) for more volts.
Now is when I'm finally getting around to attempting the 6SL7 + 6SN7.
It doesn't help that I have misplaced the manuals. I don't think adjusting the power supply only is difficult as described above in post #91.
With the manual that shipped with the Aikido, I think I remember build instructions for this combo. I'm tempted to just go ahead with only that change to the PSU. For the octal manuals online they are for a different version and do not list the combo I would like to use.
I find it best not to ask for two suggestions in one post - but...
I don't have any 6SL7 yet, and have two types of 6SN7's. Electro Harmonics and old cheap Russian equivalents which are microphonic.
Try using the cheap tubes and save the Electro Harmonics for a rainy day, while buying (Tung-Sol reissue?) a pair of 6SL7's. Using 6SL7's all around simply costs more. When I look at spending that much I want to put the money towards an Impasse.
And to make the mistake of yet another point... will I get enough voltage from 6SN7 to even test listen to an F4? Even at low volume?
It doesn't help that I have misplaced the manuals. I don't think adjusting the power supply only is difficult as described above in post #91.
With the manual that shipped with the Aikido, I think I remember build instructions for this combo. I'm tempted to just go ahead with only that change to the PSU. For the octal manuals online they are for a different version and do not list the combo I would like to use.
I find it best not to ask for two suggestions in one post - but...
I don't have any 6SL7 yet, and have two types of 6SN7's. Electro Harmonics and old cheap Russian equivalents which are microphonic.
Try using the cheap tubes and save the Electro Harmonics for a rainy day, while buying (Tung-Sol reissue?) a pair of 6SL7's. Using 6SL7's all around simply costs more. When I look at spending that much I want to put the money towards an Impasse.
And to make the mistake of yet another point... will I get enough voltage from 6SN7 to even test listen to an F4? Even at low volume?
Email John. He'll send the proper ones.
.
Finishing this will cost a whole lot less than an Impasse - that's a pretty expensive design.
Of course you will.
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