Hello,
this Autum I´ll renew my analog setup. The attached Preamp will be one Part of the new Setup. What do you mean? Will it work?
Best regards
Dieter
this Autum I´ll renew my analog setup. The attached Preamp will be one Part of the new Setup. What do you mean? Will it work?
Best regards
Dieter
It's very complicated and still missing volume control and input selector. Input is prone to problems with an open
capacitor ( it should have a ground reference). Otherwise it might work fine.
capacitor ( it should have a ground reference). Otherwise it might work fine.
The complicated Part ist the Voltage-Control-Part. The Preamplifier itself ist not complicated.
There will be a Volume-Control in the Front of the preamp. I must look If it will be a stepped version or a pot. If I go with the stepped one then I must parallel it with a resistor to be safe.
There will be a Volume-Control in the Front of the preamp. I must look If it will be a stepped version or a pot. If I go with the stepped one then I must parallel it with a resistor to be safe.
How much gain are you trying to get out of the preamp?
How much gain do you actually need from a preamp?
Are C5 and R15 for power supply noise cancellation?
How much gain do you actually need from a preamp?
Are C5 and R15 for power supply noise cancellation?
Yes, C5, R15 and R14 are, so Broskie said, are for noise cacellation. How much gain I need ist something I can't say. The Input will be at 500mV. The Power-Amp will be build later. EL84 PP with only a little bit of negative Feedback, say 6dB or 10dB. ECC88 Input and Phase Inverter could be nice.....
Re: "ECC88 Input and Phase Inverter could be nice....."
Have you looked at SY's Impasse Preamplifier?
https://audioxpress.com/article/The-ImPasse-Preamplifier
Have you looked at SY's Impasse Preamplifier?
https://audioxpress.com/article/The-ImPasse-Preamplifier
Thank you for the Link. A few weeks ago I ready about the Impasse. My Design can make a gain up to 23 with a capazcitor parallel to the Cathode-Resistor under the E288CC.
So I thougt I will have enough Gain to drive a low Gain Power-Amp.
So I thougt I will have enough Gain to drive a low Gain Power-Amp.
Maximum f/k voltage for ECL805 is 200V, this needs it's own filament winding.
E288CC has a limit of 150V maybe the 2 channels can share the same catodefollower and have it's filement elevated to a reasonable value.
E288CC has a limit of 150V maybe the 2 channels can share the same catodefollower and have it's filement elevated to a reasonable value.
Yes, I have four 6,3V secondarys for Filament. One for the EZ81, two for the ECL805 and one for the Preamp-Tubes. The Preamp Tube Filaments (1*E288CC+2*ECC88) so the plan, will be lift to 100V -> =Ub/2. For the ECL805 I see the 85V from the Stabilizer-Tube as lift-poit.
Good, you have thought this over.
( EZ81 is isolated for Vf = grounded , but you have this covered already)
( EZ81 is isolated for Vf = grounded , but you have this covered already)
I see a point in small boards with the tube socket directly attatched. Possibly 90 degrees angled to save space.
A board containing a complete part of an amp is a convenient item, easy to repair, easy to modify or replace.
I do not see any point in separating the tube itself and the logic.
A board containing a complete part of an amp is a convenient item, easy to repair, easy to modify or replace.
I do not see any point in separating the tube itself and the logic.
Sorry wrong thread, please ignore
Maybe the higher forces/moderators could erase post #12 13 and 14 post #12 was my mistake.
Maybe the higher forces/moderators could erase post #12 13 and 14 post #12 was my mistake.
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