One gripe I have with the kit, and the circuit design, is there seems little consideration of the disk warp component of the signal. This is most 'annoying' in the 8 to 13Hz region where pickup/arm resonance can add to the disk warp and create large signals. There is nowhere on the board to add a sub-sonic filter. OK, there is loads of 'headroom', but allowing such frequencies through to the power amp is asking for latching up and popped speaker cones.
Great video again Stephe. After the r8 now you again inspired me to learn more about another big piece or the audio chain. Hopefully you will make more videos about this phono in the future. Or maybe more R8 optimizing if you have the chance haha.
@@SkunkieDesignsElectronicsafter watching them twice I decided to pull the trigger this Friday. I went with a prebuilt unit from china at a very good price. I will spend some time with it stock and replace Riaa components and coupling caps with better quality ones later. Thanks for the videos Steph ❤
5:03 (I paused) ahh Cap's backwards! Gotta admit i never thought of that (hazarded a few guesses earlier) .. interesting how it can still give modest gain with 6-7 v on the plate ;) Happens to the best of us, rite xxx ?
With the volume control on your amp. Every attempt I have seen to reduce the gain on this amp by using different tubes or inserting resisters negatively impacts the sound.
The pot on the input of the amplifier shunts excess system gain to ground. Or does you system have no volume control? Like I said, several people have attempted to reduce the output gain of this pre-amp swapping other tubes or inserting voltage dividers between stages and every time it negatively impacts the sound. I'm more interested in the output of the system than the semantics of what a volume control is called.
One advantage of toroidal transformers I only recently became aware of is the ability to add your own low voltage output winding. In Michael Beeny's YT video, 'Adding a 12 volt winding to the Quad 405 Transformer', he does exactly that by just winding some insulated single core wire around part of the toroidal.
Oh yeah, I did that in my Vox-alike Amp build - no LT Winding - no problem! (The orig transformer made plenty HT volts but WAY under powered .. Hence this funky Toroid that JUST fit . Sadly THAT build along with a Mountain of other stuff got destroyed in the Eviction .. But i kept the schematics, and I've got something brewing..:) )
Oh and you wanna hear something REAL sad? In the selfsame Eviction were two Quad 405's basically - a company had built them into 2 new chassis, I picked them up in some funky junk once and - they were niiice...
hey stephe yes the video is educational. I got the zhili kit and measured all the parts. only the nine 400V 22uF caps differ, they are 33uF nominal and 29uF measured. Do you recommend buying the smaller rated 22uF or can I leave the 33uF as this caps seem to be for DC stabilization? Other question: I bought a torodial transformer with a shielding cap. Do you recommend to buy old school EI transformer instead? or try and see if there will be any problems with the torodial? what is basically the problem with torodial transformers? I allways thougt they were better. kind regards burkhard
The transformer thing is just personal preference. If you haven't watch the layout videos, please go watch those before you start moving things around or using a different chassis layout. I get LOTS of emails from people who decide to change things all around for mostly aesthetic reasons, and end up with hum and other noise issues. As far as the caps, 33uf will work fine as these are just smoothing/decoupling caps.
thanks a lot! no I strictly want to comply with your layout and also bougt the hammond chassis and choke from america... 25$ shipping 😂. only deviation is the transformer. I will try to do everything else exactly like you did, check if it works and buy EI transformer if there are any problems...
Diagnosis is a fun process. Well done
More to come...
Great troubleshooting video for everyone on what could happen both soldering in backwards or even component level issue
Very useful troubleshooting vid, thanks, Stephe!
i got a bunch of Ukraine 6n2p for initial stage, with adapter. we shall see. i might use throughout. i know gain isn't quite the same but it might be
I bet you don’t do that again. That’s how we learn. Thanks Stephe you are appreciated
Bet she does 😂
Thanks for this, easy mistake to make. I paused the video and tried to find it myself but i didn't pick up on it
I won't do that again!
Happy New Year!
🎉 Woot!
Great troubleshooting video!
One gripe I have with the kit, and the circuit design, is there seems little consideration of the disk warp component of the signal. This is most 'annoying' in the 8 to 13Hz region where pickup/arm resonance can add to the disk warp and create large signals. There is nowhere on the board to add a sub-sonic filter. OK, there is loads of 'headroom', but allowing such frequencies through to the power amp is asking for latching up and popped speaker cones.
amzn.to/3UTpdNZ or wire up your own subsonic filter on the input if you have this issue.
Great video again Stephe. After the r8 now you again inspired me to learn more about another big piece or the audio chain. Hopefully you will make more videos about this phono in the future. Or maybe more R8 optimizing if you have the chance haha.
I've done two complete build series on it :)
@@SkunkieDesignsElectronicsafter watching them twice I decided to pull the trigger this Friday. I went with a prebuilt unit from china at a very good price. I will spend some time with it stock and replace Riaa components and coupling caps with better quality ones later.
Thanks for the videos Steph ❤
5:03 (I paused) ahh Cap's backwards! Gotta admit i never thought of that (hazarded a few guesses earlier)
.. interesting how it can still give modest gain with 6-7 v on the plate ;)
Happens to the best of us, rite xxx ?
yeah I didn't expect that.
Hi...how do i reduce the gain of the preamplifier. Thanks
With the volume control on your amp. Every attempt I have seen to reduce the gain on this amp by using different tubes or inserting resisters negatively impacts the sound.
volume is not gain. But i understand.
The pot on the input of the amplifier shunts excess system gain to ground. Or does you system have no volume control?
Like I said, several people have attempted to reduce the output gain of this pre-amp swapping other tubes or inserting voltage dividers between stages and every time it negatively impacts the sound. I'm more interested in the output of the system than the semantics of what a volume control is called.
One advantage of toroidal transformers I only recently became aware of is the ability to add your own low voltage output winding. In Michael Beeny's YT video, 'Adding a 12 volt winding to the Quad 405 Transformer', he does exactly that by just winding some insulated single core wire around part of the toroidal.
Oh yeah, I did that in my Vox-alike Amp build - no LT Winding - no problem!
(The orig transformer made plenty HT volts but WAY under powered .. Hence this funky Toroid that JUST fit . Sadly THAT build along with a Mountain of other stuff got destroyed in the Eviction ..
But i kept the schematics, and I've got something brewing..:) )
Oh and you wanna hear something REAL sad? In the selfsame Eviction were two Quad 405's basically - a company had built them into 2 new chassis, I picked them up in some funky junk once and - they were niiice...
hey stephe yes the video is educational. I got the zhili kit and measured all the parts. only the nine 400V 22uF caps differ, they are 33uF nominal and 29uF measured. Do you recommend buying the smaller rated 22uF or can I leave the 33uF as this caps seem to be for DC stabilization? Other question: I bought a torodial transformer with a shielding cap. Do you recommend to buy old school EI transformer instead? or try and see if there will be any problems with the torodial? what is basically the problem with torodial transformers? I allways thougt they were better.
kind regards burkhard
The transformer thing is just personal preference. If you haven't watch the layout videos, please go watch those before you start moving things around or using a different chassis layout. I get LOTS of emails from people who decide to change things all around for mostly aesthetic reasons, and end up with hum and other noise issues.
As far as the caps, 33uf will work fine as these are just smoothing/decoupling caps.
thanks a lot! no I strictly want to comply with your layout and also bougt the hammond chassis and choke from america... 25$ shipping 😂. only deviation is the transformer. I will try to do everything else exactly like you did, check if it works and buy EI transformer if there are any problems...
“An expert is a person who has made all the mistakes that can be made in a very narrow field.” - Niels Bohr
Those things happens 😂
Ugliest thing they’ve ever seen?! 🤷♂️ Serenity now….🤦♂️
Oh it a super nasty comment lol I hope they feel better now.
I bet that looks nice with your other amps. Designed for performance rather than looks. But I think it looks OK, sort of old school.
@@SkunkieDesignsElectronics Ah, geez….Hope they’ve found a nice patch of sand to pound.