bluesman
New member
A while back I posted a rant about the Marantz Music Angel that I had my son buy blindly for me in Cape Town. Initially all the tubes were bad and it used a Chinese proprietary 6Z4 7 pin miniature rectifier that is all in all a 6X4 that is taller and pins out differently. I made a right angle adaptor and used a 6X4 in its place. All was fine for a couple of weeks than it started to sound muddy and distort. I should also say that I recently built a PP 6V6 UL amp using 6SL7?s for phase inverters, all this for a little system in my workroom to replace the SS Marantz unit that I had been using. This is a sweet and warm little amp driving Altec Lansing 3 way speakers that I de-foamed years ago and had reconed with shellacked edging.
When the Music Angel went south on me, I began calling it the Music Whore and it ended up on a pile of projects destined to last for years or to be tossed. I don?t like SS stuff much, but my spare Conrad Johnson PV1 tube preamp is on loan (probably permanently) to a friend in Dundee who emails me guilt 3 times a year about the prospect of me reposing it. So, I put into service a McIntosh SS C26 preamp. It is a quality piece but there is a hiss embedded in the sound. I took it to the Mac people in San Francisco when I lived there and they said it met the signal to noise ratio parameters for the preamp, but there is a slight hiss, I swear. It?s worst on the center channel output.
A few beers later, I decided to swap the Mac with a quality Proton SS preamp, and the left channel is slightly weak, first time I?ve used it in 10 years. I was not in a good mood. I really hate SS stuff.
The Music Whore came off the pile of stuff I hate to work on and made it to my bench. Initially I put in 2 new Mullard 12AX7s / ECC83 and a special quality Tele red dot 12AX7 ECC82. When the muddy sound occurred I retested them and they tested new: on an AVO MK IV, a Western Electric KS15751 L1 and a Triplett Mutual Conductance tester. My Bell Labs training told me that whenever the solution looks impossible, go quantum. I stuffed in all new boxed NOS RCA tubes and the unit sounded beautiful. I use John Hammond?s ?Got Love If You Want It? as a reference because of the vocals and the electric and acoustic instruments on different tracks. I heard all the nuances, the delicate changes and the emotion of the music. The whore once again graduated to an angel?. For the time being?.
I have a 6SC7 tube that tests new on any tester but will not work in any circuit and, trust me, this is not my first tube rodeo. One of the above mentioned tubes, possibly more, are nasty and deceiving. (no shorts, gas or drifting Gm)
It is my hope that anyone experiencing this same difficulty can learn from my frustration. Bear in mind that this system is my tool room audio, the old car in the family, but now I love it.
Mark
P.s. Prekash, If you feel up to tackling a couple of SS preamps that work, but not to my standards, let me know. I hate SS stuff.
When the Music Angel went south on me, I began calling it the Music Whore and it ended up on a pile of projects destined to last for years or to be tossed. I don?t like SS stuff much, but my spare Conrad Johnson PV1 tube preamp is on loan (probably permanently) to a friend in Dundee who emails me guilt 3 times a year about the prospect of me reposing it. So, I put into service a McIntosh SS C26 preamp. It is a quality piece but there is a hiss embedded in the sound. I took it to the Mac people in San Francisco when I lived there and they said it met the signal to noise ratio parameters for the preamp, but there is a slight hiss, I swear. It?s worst on the center channel output.
A few beers later, I decided to swap the Mac with a quality Proton SS preamp, and the left channel is slightly weak, first time I?ve used it in 10 years. I was not in a good mood. I really hate SS stuff.
The Music Whore came off the pile of stuff I hate to work on and made it to my bench. Initially I put in 2 new Mullard 12AX7s / ECC83 and a special quality Tele red dot 12AX7 ECC82. When the muddy sound occurred I retested them and they tested new: on an AVO MK IV, a Western Electric KS15751 L1 and a Triplett Mutual Conductance tester. My Bell Labs training told me that whenever the solution looks impossible, go quantum. I stuffed in all new boxed NOS RCA tubes and the unit sounded beautiful. I use John Hammond?s ?Got Love If You Want It? as a reference because of the vocals and the electric and acoustic instruments on different tracks. I heard all the nuances, the delicate changes and the emotion of the music. The whore once again graduated to an angel?. For the time being?.
I have a 6SC7 tube that tests new on any tester but will not work in any circuit and, trust me, this is not my first tube rodeo. One of the above mentioned tubes, possibly more, are nasty and deceiving. (no shorts, gas or drifting Gm)
It is my hope that anyone experiencing this same difficulty can learn from my frustration. Bear in mind that this system is my tool room audio, the old car in the family, but now I love it.
Mark
P.s. Prekash, If you feel up to tackling a couple of SS preamps that work, but not to my standards, let me know. I hate SS stuff.
