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Garage Stereo

Discussion in 'DIY Lounge' started by Mike B, Apr 19, 2009.

  1. jasn

    jasn Well-Known Member Donor Top Poster

    Looks great Mike. It is a sweet amp. Dead quiet with the right tubes. Enjoy! Just be careful on the reach-around to turn it off.
  2. Mike B

    Mike B Well-Known Member Donor War Zone Member Top Poster

    What tubes are you using? I'm running a pair of Tung Sol 12AU7's for the drivers and a used RCA clear top pre-amp. Tung Sol 6550's output.

    Just ordered up 4 of these, 20% off sale - :)
  3. jasn

    jasn Well-Known Member Donor Top Poster

    I started with tubes by Bob Latino; 3 Beckman 5963 12AU7's and Sovtek KT88s for power. I've since replaced the Sovtek's with Gold Lion KT88's and tried an eBay Mullard CV4204 in the center spot, which I liked a lot, but it was kinda scratchy so I'm back to using the 5963.

    It's all good to me, actually. I did just buy a NOS Valve Electronic CV4204 (Mullard-made) from the UK that I'm hoping for better results.
  4. Mike B

    Mike B Well-Known Member Donor War Zone Member Top Poster

    If you haven't already, try one of those used Conn clear tops in the middle. The RCA ones are the best. Still on ebay for less than $20 ea.

    I got better results with the Tung Sols on the sides, but that clear top is a sweet amplifier tube.
  5. GHilinski

    GHilinski Active Member War Zone Member

    That is a nice sounding toaster!
  6. GHilinski

    GHilinski Active Member War Zone Member

    I have to get around to re-rubing my guitar amp some time soon and dreading it. I have "Groove Tubes" in it now but am thinking of going with J&J's. The Groove Tubes were touted as US made but you can see they were made in russia and silk screened over with a US made logo.
  7. Mike B

    Mike B Well-Known Member Donor War Zone Member Top Poster

    What's in your amp? What "groove tubes" do you have?

    Got the sub amp replaced, a Dayton 250 replaced the old Rythmic Audio. Works good and triggers faster than the old Rythmic which wouldn't "auto on" at low levels.


    Was going to do more but my giant "bin box" kit arrived and I put that together. Got a place to store all my "bits" in a somewhat organized manner.
  8. chad

    chad Active Member War Zone Member Top Poster

    I think that's the same amp I used for my first IB with 2 Dayton 15s. Was a good rig for sure and that amp never batted an eye. Enjoy.

    Sent from my iPhone using Tapatalk
  9. GHilinski

    GHilinski Active Member War Zone Member

    Three 12ax7's preamp and two EL-34's power tubes. Typical Fender tweed layout for a single channel low power amplifier. It also has a fat switch which increases the plate voltage to the tubes so they break up a bit more at higher volumes. When I was playing single coil pickups in my Telecasters, a Stratocaster and a Gibson Blues Hawk, it sounded great. The I sold them and bought the Paul Reed Smith guitars, the hotter pickups buried the amp making the bass and midrange sound awful. The JJ's will really tighten up the mid and bottom end but still give the sparkle of the groove tubes.

    I've also gone to lower output pickups in two guitars but the two with overwound high gain pickups are now the problem. I thinking he total fix will be about $55 plus shipping. I'm also looking at the Mullard reissues and Mesa Engineering tubes (Mesa Boogie) which will be much more expensive. I know the question will be why change when you liked the sound. The answer is simple. I wanted to get more of a modern american sound vs. the vintage tone I had for a long time and some collectable guitars that are works of art.

    P.S. Mesa Boogie amps are made by a company called Mesa Engineering. If you look at Carlos Santana's guitar rig and see a little amp on top, that is one of the original prototypes. The company name is called Mesa Boogie because Carlos tried the amp and said "That thing really boogies!" The name stuck and the amp always sits next to a picture of Jesus. Maybe that is where he gets his tone? :)
  10. Mike B

    Mike B Well-Known Member Donor War Zone Member Top Poster

    Got my sliding shelf installed with the exciter below so's it don't get cooked by the heat.


    I can slide the amp out, remove the cover and set the bias as needed. Need another day before the amp goes in as the varnish is still a bit tacky.

    Tomorrow I expect a day of sonic bliss - :)
    jasn likes this.
  11. Mike B

    Mike B Well-Known Member Donor War Zone Member Top Poster

    I have sonic bliss in the garage - :)


    Tingle and shiver good. So good you just want to stand and listen for hours. Slider works good, heavy duty full extension, that heavy amplifier moves nice and easy and stable. Gotta move those cables to the slider shelf, probably use a "loose fit" cable clamp.

    Gotta get rid of the car amp on the wall and the extra cables. Eventually the head unit will be battery powered, I have a slick plan to do this and keep it charged as well as switching the ST120 on and off w/o needing to reach in back. Ordered up a 12 volt coil DPDT relay. The switch that triggers the head unit will also power the relay coil. AC line to the middle contacts. When the head unit is turned on the contacts will switch the ST120 on. When the switch is off the relay will turn on the battery charger. Beauty. A power failure will never cause me to go through the head unit set up routine or restore all the stations programmed. No charger noise will be introduced when the radio is on. Just going to be one of those little 1 amp automatic maintainers, nothing serious.
    Jack likes this.
  12. chad

    chad Active Member War Zone Member Top Poster


    Sent from my iPhone using Tapatalk
  13. Mike B

    Mike B Well-Known Member Donor War Zone Member Top Poster

    Hey Chad, I got a big pile of goodies here with your name on them. I saved that industrial strength box the Mundorfs came in and those nice thick poly foam spacers should hold the amps nice and safe. I'll be putting that together soon!
  14. chad

    chad Active Member War Zone Member Top Poster

    Awesome! I'll send you my address.
  15. claud

    claud Well-Known Member Donor

    For a retired guy, you are the busiest guy i know!! And you do not do anything half way!!
  16. GHilinski

    GHilinski Active Member War Zone Member

    Nice rig. You still using the Sonic Exciter?
  17. Mike B

    Mike B Well-Known Member Donor War Zone Member Top Poster

    Yeah Baby!

    It still makes an improvement although the tube amp needs less help than the sterile solid state.

    It's a cool product and made in USA - :)
  18. Mike B

    Mike B Well-Known Member Donor War Zone Member Top Poster

    Relay box done;


    Battery (35 amp-hour AGM) and smart charger here too. Relay box is on the wall and I'm going out to install the battery and charger and re-program the head unit.
  19. Mike B

    Mike B Well-Known Member Donor War Zone Member Top Poster

    Battery, charger and relay box installed and working great.


    I was out there and diggin' the tunes when I thought I'd try the new KT88's, so I shut down and waited for the caps to discharge and put in the left side finals. Powered up and I thought they were just a tad smoother by going back and forth listening. Shut down and went to lunch. Got back and popped in the other 2 for the right side. Switched on and the tubes started glowing and right about 3o seconds later there was a loud pop from the right speaker. Me thinks the plate arced to the supressor grid as the bias voltage was 20 volts. Tube was not hot either and disassembly and testing revealed the 10 ohm 2 watt bias resistor was now 6.8 meg. Not burned or broken, no smoke, just open circuit. Yeah Jim, should have ordered some resistors with the fuses.

    Oh well, got some ordered now. I guess I'll stick with 6550's as they have a rep for rugged. But no tunes..., no wait, I have spare amps! Now playing until the resistors arrive, my first tube amp which still works great;


    I purposely over drove this to see how tubes sounded clipped and it's true about "soft clipping". Tubes just sound "muddy" when clipped vs transistors which sound harsh and painful.
  20. jasn

    jasn Well-Known Member Donor Top Poster

    Sorry about that Mike. I had the same thing happen to me swapping over to the Gold Lions. That 10 ohm resistor saved me quite a few bucks for a new tube.

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