Modwright Oppo BDP-105 Best tubes to reduce glare and harshness JBL 4312a

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  • Jr. Member
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Hi All,

First post I think...

I am a proud owner of a Modwright-Oppo BDP-105 with “Truth” Modifications.  I love it.  But I think I'd like to make some changes to the tubes to compensate for a perceived deficiency in my speakers--JBL 4312a's. I know probably not a good idea...but I can't find anyone that will do custom crossover work for me.

These speakers are crazy midrangie!  I am looking for more contour in my midrange.  I am not interested in 'warmth', just something that really 'rounds' the midranges a bit, without compromising the three dimensional quality of the sound stage.

Any suggestions on tubes that will add more contour and pleasant shape to the mids?

I also welcome any opinions regaurding my speakers.  With various experiments 'doping' the speakers with different types of fabrics, the frequencies that are the problem are actually coming off the woofers--these are the white ridged paper cones.

Thanks much!


  • Industry Participant
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I am also an owner of the Modwright/Oppo unit and have never experienced what you describe. I would suggest speaking with Dan Wright for his recommendations. He is knowledgable of the tube options, and can also help in obtaining them.

Ern Dog

You have a killer source!  Don't waste time trying to compensate, instead get new speakers!  Rolling tubes will only be a temporary band aid for your speakers. In the mean time, I used to have the Modwright Oppo 83 and found that a Mullard rectifier tube will round things out some.

Which tubes are you using now?


 I too am a very happy 105 Oppo/Modwright Truth Mod user and have to say if you still having midrange glare/harshness ( or whatever you might call ) it using the Modwright Oppo combo it is not the tubes you should address. It is more than likely you Speakers and or Cables being the culprit . The Old Stock 5AR4 Mullard will help smooth things out somewhat ( but hurt in other areas ) . I still feel the Phillips 5R4GY is much better than the Mullard ( in this situation ) ......

Maybe try some headphones to see if what your hearing is the same as what your hearing with your JBL's...My guess is you need to upgrade from JBL's to something more compatable ( and in the same league ) with you Digital player.........


  • Full Member
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The JBLs are great speakers, try this:

Call Andy at vintage tube services and ask him explaining what you're after.  I'd give a 1950s RCA 6SN7 a try with a GE Rectifier in the PS.

Good luck