REVISED TUBE CONSOLE SCHEMATIC- Questions???

[thakava]

I can show you a picture of my early version! But the new version will take some time! I only have some concepts drawn up.

View attachment 134925
(THE OG)

View attachment 134926
(THE NEW VIBE)

Loooks cooool!
Following this thread...

 

[thomasdf]

I just watched EBay for a while. The ones in the pic are true vintage, but I have a few repro that look pretty legit! Got most of them pretty cheap, but paid more than I would have liked to for a couple.

If you feel like sharing a link for these repro, I am interested because I never dared to pull the trigger. To know they are validated by someone owning / touching / using the the real ones would help me
Dont want to hijack the thread, though !
Cheers

 

[HappyHourStudio]

If you feel like sharing a link for these repro, I am interested because I never dared to pull the trigger. To know they are validated by someone owning / touching / using the the real ones would help me
Dont want to hijack the thread, though !
Cheers

Unfortunately, the repro ones I found were also second hand on EBay.

I just did a brief look and didn’t see anything up for grabs at the moment.

 

[HappyHourStudio]

Loooks cooool!
Following this thread...

Thank you!!! Excited to share once it’s done!!!

 

[HappyHourStudio]

Note that if you insist on grounding input center tap, that you'll compromise

- Phantom power will be shorted
- unbalanced (e.g. minus to ground) will not work
-your cmrr can be significantly impaired depending on the precision of transformer winding and symmetry.

I have an old AKG phantom power supply that I’d be using ahead of the console before the mic inputs, would this still not work???

 

[beatnik]

Tayda stocks the RCA repro knobs

https://www.taydaelectronics.com/catalogsearch/result/?q=rca+knob

 

[HappyHourStudio]

Tayda stocks the RCA repro knobs

https://www.taydaelectronics.com/catalogsearch/result/?q=rca+knob

I think what thomasdf is referencing are the large 60mm RCA knobs, which (unfortunately) Tayda doesn’t sell. Which sucks because those prices are pretty solid!

Thank you for the recommendation though! Have you used these before?

 

[HappyHourStudio]

Here’s the first channel strip to give you guys an idea of what I'm working on! Obviously no connections and the input transformer isn’t in place yet. Likely going to mount it under the big knob.

 

[Brian Roth]

Is the front panel steel so it doesn't sag?

Bri

 

[gyraf]

..sorry for persevering, but your grounded-centertap input transformer continues to bother me: Even with an external, capacitor-isolated phantom power supply, it relies very much on a 100% floating and symmetrical source

Which means that any impedance-balanced electronic balancing will partially short out.

So incompatible with all the new Neumanns etc..

/Jakob E.

 

[HappyHourStudio]

Is the front panel steel so it doesn't sag?

Bri

The panel and support are both steel, mmm hmm.

 

[HappyHourStudio]

..sorry for persevering, but your grounded-centertap input transformer continues to bother me: Even with an external, capacitor-isolated phantom power supply, it relies very much on a 100% floating and symmetrical source

Which means that any impedance-balanced electronic balancing will partially short out.

So incompatible with all the new Neumanns etc..

/Jakob E.

I appreciate the perseverance! So would I just need to leave that connection off to fix the issue? Or would this require some rerouting?

Thank you!

 

[gyraf]

..yes, it would be as simple as just leaving the center tap unconnected..

 

[HappyHourStudio]

..yes, it would be as simple as just leaving the center tap unconnected..

Ok. Groovy. Question…. Is there any particular reason the schematic would have had the ground hitting the center tap? Would installing a toggle switch be a good idea?

 

[gyraf]

for a mic input, I can't see any scenario where you'd want the grounded primary. Never seen such connection irl

 

[emrr]

for a mic input, I can't see any scenario where you'd want the grounded primary. Never seen such connection irl

Agreed, but just to note, almost all of the RCA tube preamps are CT grounded. The output side frequently is too. With some of their inputs, the shield is attached to that CT such that you must leave them grounded. Not a modern thing at all, not a thing that exists after the arrival of T-power or 48V. You do see the CT used as the 48V source, with half the series resistance.

 

[HappyHourStudio]

Agreed, but just to note, almost all of the RCA tube preamps are CT grounded. The output side frequently is too. With some of their inputs, the shield is attached to that CT such that you must leave them grounded. Not a modern thing at all, not a thing that exists after the arrival of T-power or 48V. You do see the CT used as the 48V source, with half the series resistance.

Okay. Thank you for the input! That would make since because this is based off of an old modular RCA design that uses an RCA input transformer. So I should leave this connected is what you’re saying? And just not use anything with phantom power running through it?

 

[emrr]

No you shouldn’t. I lift them if it works, and you’re not using the orig.

 

[gyraf]

..as I understand it, 48V-through-center-tap won't work with impedance balanced mics like the Neumanns, as the "dead" side will short half the primary..

 

[emrr]

..as I understand it, 48V-through-center-tap won't work with impedance balanced mics like the Neumanns, as the "dead" side will short half the primary..

Ah, so that super-cedes the original 48V CT idea. I've got a few things that are CT fed, I suppose they've not encountered a mic like this yet. That also means those mics accept only half the potential current? Or it's a power path but not an audio path? I've not looked at a schem....