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    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Music Angel pre-amplifier - few modifications

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#21
if you want the inputs back, make your selector board small enough to mount directly on the lugs from the RCA inputs. Then you need 2 signal lines and the control line from the main switch. I am thinking of building a selector board using reed relays to switch.
an old one I have with CD4066 works really well.
 
#22
stocktrader200 said:
if you want the inputs back, make your selector board small enough to mount directly on the lugs from the RCA inputs. Then you need 2 signal lines and the control line from the main switch. I am thinking of building a selector board using reed relays to switch.
an old one I have with CD4066 works really well.
Click to expand...

Thanks for your suggestion. I use only dac as source. In fact I split the DAC output between this music angel pre and another cost effective but great sounding tube pre that is little bear p3.
 
#23
I have been building some tube circuits inside the two main recievers I have.
They are pioneer SX 780 and SX 3700. If you want tone controls, you can drive a passive tone circuit like in the SX 780 with a 6922 or buffered ( 2N5551 ) 12AX7 positioned after the Volume controls. Set gain of the tube stage to match amplifier output to desired level.
If you use the Pioneer circuit the load impedance is 43k and both pots are 100k. Tube loading is around 50k with both pots centered. response is ruler flat from 30 - 20000 Hz centered.
sub bass drop of about 1 db. Sounds fantastic as adjustments are more gentle with tube preamp
 
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#24
stocktrader200 said:
I have been building some tube circuits inside the two main recievers I have.
They are pioneer SX 780 and SX 3700. If you want tone controls, you can drive a passive tone circuit like in the SX 780 with a 6922 or buffered ( 2N5551 ) 12AX7 positioned after the Volume controls. Set gain of the tube stage to match amplifier output to desired level.
If you use the Pioneer circuit the load impedance is 43k and both pots are 100k. Tube loading is around 50k with both pots centered. response is ruler flat from 30 - 20000 Hz centered.
sub bass drop of about 1 db. Sounds fantastic as adjustments are more gentle with tube preamp
Click to expand...

Hi,
Thank you for your advice. I have gradually learnt that the tone control is actually not needed in my setup. I use a notebook--> smsl m8 DAC--> music angel pre--> heavily modified quad 405 --> Dali Ikon 6 MK 2 speakers.

I am getting the psvsne 12au7 tube the day after (replacement for genalex gold lion b749) and then ill let you guys know. Did i mention that i rewired the pre with silver coated ofc copper cable? It did sound very good to me initlally having great detail as in highs and upper mid range. I really liked the sound very much for a few initial days. Now i think i miss the old copper wiring sound. Well it did make so much of a diference for me. I cant say for those who say yhe wiring makes no difference.
Thanks
Nitin
 
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