Thanks for the video. The walkthrough and explanation of the grounding was ace! Also, great thinking on the drop in pcb! I expect to see a lot more of these drop in solutions in the future. The combination of Kicad and the ease of pcb manufacturing is going to add a lot of life to these old amps. Thanks for sharing this.
Just found your channel. I love how you show the WORK, and not your face, 90% of the time like many others do. You also use a slim pointer stick instead of your finger, which many do. Subscribed!
If it's a quality through hole, heavy plated 3mm FR4 PCB, I would prefer it over something that's hand wired. If the PCB is correct, it cuts out opportunity for mistakes. It cuts down on labor and they can look really cool these days with all of the solder mask color options. The guy that runs the Headfirst Amplification CZcams channel sells amazing Marshall-esque PCB's. I've been meaning to order one....
In their heyday, Ampeg did a great job of meeting the changing needs of bass players; the increasing size and power of these monster amps was just the natural response to the demands of the time.
Been here and thought the earthing was crazy. The idea of dropping the preamp Signal down and reamplifying the levels up is also crazy. I have seen the 10 ohm resistor in the black Japanese SVT reissue amps. They used all 12AX7’s.
This is such a great way of tackling this issue. Especially now that Nichicon and others have discontinued so many of their axial cap lines. I've been considering doing something similar for my 70s Traynor that needs a cap job. Or perhaps a turret board with radial caps on their side like you did on your AC-style custom build...
A PCB will accept radial caps just as well as it will snap in caps. I'm on-board 😁 with printed circuit boards for this application; *but I don't like using double-sided boards for "snap-in" caps because they can be fairly difficult to remove from a double-sided board even with a vacuum operated solder sucking station*. It can be difficult to get all the solder out from both sides of the plated-through rivet to remove the cap, and solder-wick won't help you.
Lyle, Found the answer to my other question about those can caps here! Thanks as always ! How does the grounding from the preamp chassis interface exactly with the power amp ? Are the input jacks isolated? Are the audio and power grounds separated from each other and isolated from chassis ? Where do I send a thank you care package for all your wonderful educational material? What do you like besides coffee? 😁 Cheers Lyle! Charlie
The original output tubes in early SVT's were 6146B's, a small transmitting tube with the plate connection on top. Also, V2'S, V4's and VT22's originally used 7027 output tubes.
Both you and Brad are making clever PCBs. :-) FWIW, I saw that RSD Sound has a Bogner heater power supply module, and was reminded of your Shiva videos. I don't remember if the module you mentioned was for the heaters (or just relays, etc).
I know nothing from nothing when it comes to what you're doing ( but thanks to you, my head is getting fed), however, the way you are using visual tools is WAY cool...!!!😃😎👍 VERY excited to hearing you play through your completed endeavors here😎👍🤞🤞😁 Damn...this is really cool...Thanks for showing us Lyle 😎👍❤🖖
Any idea why they thought this was a good grounding scheme, given many other methods were present at the time? Surely there is some benefit- but the trade off seems poor for reliability with the chassis connection.
random question, I really like that font you used for the hole labels, do you know the name of it? If you ever decide to build a big ass tube bass amp, sign me up!
Where is the safe ground connected to the chassis ? The SVT grounding program is a mess as you say. The 10 ohm is used in modern hi fi amps because it a reference point . The thinking is that the chassis is for safety and shielding . The circuit zero voltage leg is separated by the 10 ohm resistor to reduce noise. The 10 ohm resistor need to be big enough to be able to flow enough current so the fuses blows if there is a short . Now where this amp will benefit from that design is up for debate . My thought is do as you have done and safety ground and chassis ground at the same point on the chassis . Safety over absolute lower noise floor . Noise in these amps can come from outside sources more often than they do in Hi- Fi amps .
They have the safety ground to chassis near the power cable inlet, which is good. The schematic shows a 1/2W 10 ohm resistor, which would be laughable if it were present. But it's not. The entire chassis reference for all the actual circuitry is just that tiny shield wire going to a (loose in this case as it came in) Switchcraft jack trying to contact chassis with a toothed washer into heavy powder coating. Um, no thank you. I just finished tweaking my schematic separating the two reservoir stages' grounds from the subsequent grounds. Each will have separate chassis connections for lower ripple. And the ground wire used for shielding will be just that - not sure if I'll telescope the ground or just isolate the jack from chassis. Probably the telescope so any hash on incoming signals will go straight to chassis. Ampeg grounds are cray cray. Marshall grounds are just copying Leo's mistakes in '58 - but he corrected those starting in '61.
@@PsionicAudio The shield wire my thought would be to hook it at the chassis and cut it at the circuit . Providing the shield then dumps the noise to ground .
@Psionic Audio - This a great video! I have late 70's SVT that needs a recap, tube job etc. Are you breaking out the multicap can caps into individual caps on your PCB?
Lyle, Found the answer to my other question about those can caps here! Thanks as always ! How does the grounding from the preamp chassis interface exactly with the power amp ? Are the input jacks isolated? Are the audio and power grounds separated from each other and isolated from chassis ? Where do I send a thank you care package for all your wonderful educational material? What do you like besides coffee? 😁 Cheers Lyle! Charlie
Thanks for the video. The walkthrough and explanation of the grounding was ace! Also, great thinking on the drop in pcb! I expect to see a lot more of these drop in solutions in the future. The combination of Kicad and the ease of pcb manufacturing is going to add a lot of life to these old amps. Thanks for sharing this.
I may have just tech-geek-drooled on my iPad… Such a great idea!
Just found your channel. I love how you show the WORK, and not your face, 90% of the time like many others do. You also use a slim pointer stick instead of your finger, which many do. Subscribed!
If it's a quality through hole, heavy plated 3mm FR4 PCB, I would prefer it over something that's hand wired.
If the PCB is correct, it cuts out opportunity for mistakes. It cuts down on labor and they can look really cool these days with all of the solder mask color options.
The guy that runs the Headfirst Amplification CZcams channel sells amazing Marshall-esque PCB's. I've been meaning to order one....
Jason's a good guy and a good tech.
Fascinating how Ampeg went from the B-15s and later ended with these monsters. Of course they sound amazing!
In their heyday, Ampeg did a great job of meeting the changing needs of bass players; the increasing size and power of these monster amps was just the natural response to the demands of the time.
Been here and thought the earthing was crazy. The idea of dropping the preamp
Signal down and reamplifying the levels up is also crazy.
I have seen the 10 ohm resistor in the black Japanese SVT reissue amps. They used all 12AX7’s.
Got no love. 💔
Great info
This is such a great way of tackling this issue. Especially now that Nichicon and others have discontinued so many of their axial cap lines. I've been considering doing something similar for my 70s Traynor that needs a cap job. Or perhaps a turret board with radial caps on their side like you did on your AC-style custom build...
A PCB will accept radial caps just as well as it will snap in caps. I'm on-board 😁 with printed circuit boards for this application; *but I don't like using double-sided boards for "snap-in" caps because they can be fairly difficult to remove from a double-sided board even with a vacuum operated solder sucking station*. It can be difficult to get all the solder out from both sides of the plated-through rivet to remove the cap, and solder-wick won't help you.
I enjoyed this video and am looking forward to seeing the implementation of the new board. My Black Lab Chloe approves of the upgrades.
fantastic work. Thanks for sharing
6:22 The previous version used 6146B. Kinda cool looking with the anode connection at the top.
And so totally safe! ;)
the finger tap of smart-ness OMG, this 9 minute video is a goldmine of awesome.
Thanks Curran!
Don’t make me tap the sign….
Wow, very cool PCB creation!! Like you indicated amp already has a PCB well done
It’s like…I need my old SVT worked on and NASA showed up.
Haha what an amazing grounding scheme
Amazing isn’t the word as much as unusual.
Kicad? Very nice work.
Lyle,
Found the answer to my other question about those can caps here! Thanks as always !
How does the grounding from the preamp chassis interface exactly with the power amp ? Are the input jacks isolated? Are the audio and power grounds separated from each other and isolated from chassis ? Where do I send a thank you care package for all your wonderful educational material? What do you like besides coffee? 😁
Cheers Lyle!
Charlie
The original output tubes in early SVT's were 6146B's, a small transmitting tube with the plate connection on top. Also, V2'S, V4's and VT22's originally used 7027 output tubes.
check John Chambers SVT repair page, he does a 6146B version! They are bizarre!
Both you and Brad are making clever PCBs. :-) FWIW, I saw that RSD Sound has a Bogner heater power supply module, and was reminded of your Shiva videos. I don't remember if the module you mentioned was for the heaters (or just relays, etc).
super cool, you're going to give it modern caps!
Nice work.
Your CAD file is expressive
Very nice
I know nothing from nothing when it comes to what you're doing ( but thanks to you, my head is getting fed), however, the way you are using visual tools is WAY cool...!!!😃😎👍
VERY excited to hearing you play through your completed endeavors here😎👍🤞🤞😁
Damn...this is really cool...Thanks for showing us Lyle 😎👍❤🖖
This was really cool. I’d love to see more about how to use this type of software.
CZcams has thousands of KiCAD tutorials. A handful are actually useful too. ;)
"Get Yer Ya Ya's Out!"
Any idea why they thought this was a good grounding scheme, given many other methods were present at the time? Surely there is some benefit- but the trade off seems poor for reliability with the chassis connection.
SVTs have had pcb since day one. There was never a point-to-point wired SVT.
Exactly
Nice work. Have you put any more thought into a PCB version of the Excalibre?
Shh. The mob would come for me. But...
Say it!.
Say it!
Say it's name my bitches! 😁👍
Cheers 🍻
random question, I really like that font you used for the hole labels, do you know the name of it? If you ever decide to build a big ass tube bass amp, sign me up!
That's just KiCAD's built in system font for silkscreen labels. I don't know what they call it. But thanks!
@@PsionicAudio hah I'll find it! thanks man!!
Where is the safe ground connected to the chassis ? The SVT grounding program is a mess as you say. The 10 ohm is used in modern hi fi amps because it a reference point . The thinking is that the chassis is for safety and shielding . The circuit zero voltage leg is separated by the 10 ohm resistor to reduce noise. The 10 ohm resistor need to be big enough to be able to flow enough current so the fuses blows if there is a short . Now where this amp will benefit from that design is up for debate . My thought is do as you have done and safety ground and chassis ground at the same point on the chassis . Safety over absolute lower noise floor . Noise in these amps can come from outside sources more often than they do in Hi- Fi amps .
They have the safety ground to chassis near the power cable inlet, which is good. The schematic shows a 1/2W 10 ohm resistor, which would be laughable if it were present. But it's not. The entire chassis reference for all the actual circuitry is just that tiny shield wire going to a (loose in this case as it came in) Switchcraft jack trying to contact chassis with a toothed washer into heavy powder coating.
Um, no thank you. I just finished tweaking my schematic separating the two reservoir stages' grounds from the subsequent grounds. Each will have separate chassis connections for lower ripple. And the ground wire used for shielding will be just that - not sure if I'll telescope the ground or just isolate the jack from chassis. Probably the telescope so any hash on incoming signals will go straight to chassis.
Ampeg grounds are cray cray. Marshall grounds are just copying Leo's mistakes in '58 - but he corrected those starting in '61.
@@PsionicAudio The shield wire my thought would be to hook it at the chassis and cut it at the circuit . Providing the shield then dumps the noise to ground .
@Psionic Audio - This a great video! I have late 70's SVT that needs a recap, tube job etc. Are you breaking out the multicap can caps into individual caps on your PCB?
Thanks, yes. 12,000 hour rated 105 C caps, low ESR, high ripple rating.
@@PsionicAudio Nice! I should have asked this in the first question - what brand are you going to use for the cap job?
Sweet, are you going to batch that pcb and possibly sell them?...please, please please? 🙏
Thinking about it.
Make it work. Vintage amps aren’t works of art. Extra pcb necessary to make it sound right? Do it!
Lyle,
Found the answer to my other question about those can caps here! Thanks as always !
How does the grounding from the preamp chassis interface exactly with the power amp ? Are the input jacks isolated? Are the audio and power grounds separated from each other and isolated from chassis ? Where do I send a thank you care package for all your wonderful educational material? What do you like besides coffee? 😁
Cheers Lyle!
Charlie