leadbreath
Well-known member
3) Dont understand your question??
EAB VE12 Tube Preamp Dual Power Supply Question????
- Thread starter leadbreath
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dirty1_1garry
Well-known member
Bax wants to be driven from a relatively low source impedance, trimmer RVT1 at 100K is too big imo
/Jakob E.
/Jakob E.
dirty1_1garry
Well-known member
RVT1 is a mistake. Fixed.
VE12 as a console channel have a 100K pot, looks like a "send" pot on the original schematic. I tried to redraw the sch in the version of a preamp only without anything superfluous.
If anyone has any thoughts about input transformer, suitable output cascade and eq potentiometer values - you are welcome. From my side, I can simulate the circuit.
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I'm not 100% sure but I think I once saw something of a 1:18 ratio for the input transformer.
Or at least this was the ratio of the transformers used in the EAB MV63 preamp and EAB V65 small mixer preamps.
EDIT: yes, just saw the designation of the input transformer used in the VE12. It's EÜ1/V65. The same as in the MV63 and EAB V65 units and these have definatelly 1:18.
Or at least this was the ratio of the transformers used in the EAB MV63 preamp and EAB V65 small mixer preamps.
EDIT: yes, just saw the designation of the input transformer used in the VE12. It's EÜ1/V65. The same as in the MV63 and EAB V65 units and these have definatelly 1:18.
dirty1_1garry
Well-known member
1:18 transformer ratio. Mind blowing! 25dB of gain just from the transformer.
dirty1_1garry
Well-known member
DerEber
Well-known member
Maybe this is interesting for some of you:
https://www.kleinanzeigen.de/s-anze...ponenten-tester-mischpult/2531824296-279-7977best,
Stephan
https://www.kleinanzeigen.de/s-anze...ponenten-tester-mischpult/2531824296-279-7977best,
Stephan
paulcheeba
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- Mar 29, 2017
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I have acquired an 8 channel 2 buss RE-85 which is in a bit of a state to say the least. It is a handmade little mock up of channels in a cheap frame with a ton of din plugs and what seem's like a passive split on the outputs which must be low level. I'm planning to rebuild the back of the mixer and add walnut side cheeks as we have the most amazing metal workers in Hastings that do classic, vintage racing cars and mixable.com is superb for the wooden touches. Steven's and Billington are local too. Seeing as there are no decent outs apart from maybe the sum buss I'm thinking after talking to Rafa as he's been selling me vintage transformers, we like sub miniature SN28b-v Soviet tubes and Lundahls for this which is hopefully the way to go for direct out's as space and clarity is a priority as there should be enough colour already.
Raphael: "The circuit is a simple parafeed plate follower using half of a 6N28b. That means only four very compact pencil tubes for all eight channels. Output impedance is around 3k5, driving a 7k35:600 LL1530 load (3.5:1 ratio) and maybe a 18k8:600 LL1930 load (5.6:1 ratio)"
Or maybe some UTC's like the KB's of a similar ratio for different flavours.
I want to turn the summing into a 2 channel mic pre also as it only really need's mic transformers (either Jensen, UTC, Triad, Haufe or something British) to become EF806S, V41 type circuits so with a line pad and some pan pots we should be able to get 10 pre amps or an 8 channel mixer for 8 track retro, tape mixes. It has no pans yet just switches and some eq pots and switches feel broken or stiff. Some faders feel lose but I have spares.
"Low enough plate resistance for the Lundahl transformers. Heater voltage in series, the two tubes at 12v." Being dual E283CC everywhere apart from the bus additions and the little Soviets subs. I don't need 48v phantom as I use tubes or ribbons like with the Coils.
I just have to clean it all and reverse engineer all the nasty output wiring that is really tight, brittle and ready for the new XLR direct out installation and chassis extension. I want to keep it compact and portable.
I'll breadboard a channel first and experiment with sound as I scored a great tube power transformer with all the taps that should fit nicely for the whole mixer. I hope we don't have too many broken channel trafo's or pots etc, a recap with Soviet and /or German capacitors and fingers crossed we have it right first time. Resulting in Low noise. Good drive & low impedance without resorting to solid state.
Anyone have anything helpful to add? I'd appreciate all the input I can get from the community that I've followed here with fascination. This thread has really helped. I've only made mics so far so moving into preamps is a different world. Luckily I have fab, tech friends, workshop space, good ears and a studio I love the sound of. That gives me the confidence and inspiration to keep on trying.
Raphael: "The circuit is a simple parafeed plate follower using half of a 6N28b. That means only four very compact pencil tubes for all eight channels. Output impedance is around 3k5, driving a 7k35:600 LL1530 load (3.5:1 ratio) and maybe a 18k8:600 LL1930 load (5.6:1 ratio)"
Or maybe some UTC's like the KB's of a similar ratio for different flavours.
I want to turn the summing into a 2 channel mic pre also as it only really need's mic transformers (either Jensen, UTC, Triad, Haufe or something British) to become EF806S, V41 type circuits so with a line pad and some pan pots we should be able to get 10 pre amps or an 8 channel mixer for 8 track retro, tape mixes. It has no pans yet just switches and some eq pots and switches feel broken or stiff. Some faders feel lose but I have spares.
"Low enough plate resistance for the Lundahl transformers. Heater voltage in series, the two tubes at 12v." Being dual E283CC everywhere apart from the bus additions and the little Soviets subs. I don't need 48v phantom as I use tubes or ribbons like with the Coils.
I just have to clean it all and reverse engineer all the nasty output wiring that is really tight, brittle and ready for the new XLR direct out installation and chassis extension. I want to keep it compact and portable.
I'll breadboard a channel first and experiment with sound as I scored a great tube power transformer with all the taps that should fit nicely for the whole mixer. I hope we don't have too many broken channel trafo's or pots etc, a recap with Soviet and /or German capacitors and fingers crossed we have it right first time. Resulting in Low noise. Good drive & low impedance without resorting to solid state.
Anyone have anything helpful to add? I'd appreciate all the input I can get from the community that I've followed here with fascination. This thread has really helped. I've only made mics so far so moving into preamps is a different world. Luckily I have fab, tech friends, workshop space, good ears and a studio I love the sound of. That gives me the confidence and inspiration to keep on trying.
