Dr.bag tube amp

Discussion in 'Power Amps' started by ecline56, Sep 22, 2022.

  1. ecline56

    ecline56 Rando

    Dec 21, 2021
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    Mount Vernon,Ohio 43050
    First, I posted about this sellers most recent builds in the deals threads because I think these are excellent values and I do not think they will last long. it was suggested I do a review so here it comes. Don't have a lot of time but I can hit the highlights and add more later.

    I bought a balanced input 12AV5 power amp and matching preamp from this seller about 10 years ago; maybe longer. I think his newer builds are even better. He has improved his knowledge and he uses better parts.

    The preamp has a volume controil, four rca inputs, two rca outputs and one main out which is balanced. The preamp has bass and treble controls and a headphone out. The rwo rca outputs have six position level controls. The preamp uses 6DE7 tubes R/L and an ECC99 for the balanced output signal. I do not like the headphone amp the sound is to warm and tubey.

    The power amp uses 6GU7 x2 for input. The splitters/ inverters are 6GU7 x 2 and the power tubes are 12AV5's. The amp has a triode/ UL switch. Two volume controls to set balance/ output level. The power switch has an intermediate setting to warm up the filaments before the high voltage is applied (very smart). The amp puts out 30 watts per channel Ul and 15 per side in triode using Edcor output transformers. The amp is manual bias with pots on the back panel of the amp.

    The sound! I have used the pre separately and this pre will drive anything. Warm smooth sound overall but very dynamic with the matching amp. The power amp has good to very good resolution. The sound is musical and detailed. The amp leans to warmth and is great for rock in UL mode. I have tried triode mode but I always miss the UL mode speed and dynamics with rock. But for something like Rodrigo Y Gabriella acoustic guitars have a nice full body and do not seem to lose to much speed. The amp has good bass, excellent mids and a smooth forgiving treble which is a must for me.

    30 watts may not sound like much but with my higher sensitivity Bozak B-302's (92db/1 w/1m) they will play as loud as you can stand with room shaking dynamics. Furthermore, right now they pair is hooked up to some Speakerlab model 4's I rebuilt a couple years ago. Actually in 2017 .... time flies. The amp can drive the acoustic suspension woofers quite well with no sense of strain. I listen to mostly classic rock. But this amp is great with Blues too. Nirvana Unplugged is sublime on this amp combo.

    The amp is dead quiet. I have had zero reliability issues. I just changed tubes after what I believe to be 10+ years. The tube change cost me about $15 for the four power tubes. The signal tubes are all quiet and did not sound like they needed changed. I probably did not need to change the power tubes but I wanted to try some Sylvania 12AV5's.

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