Sunday, June 3, 2012

Carmen Ghia clone Finished!

After 9 months worth of work on and off, I finally finished building a Dr. Z Carmen Ghia clone. I built it from the old Hammond AO-35 reverb amp, given to me by Ron Ashcraft back on Monday, May 12, 2008. Building the cabinet took more time, effort, and money, than did modifying the A0-35 circuit. I took lots of photos of the entire process. I will put them all out on a photo dump in the future. The amp sounds great but has more gain than I need around the house, so I've swapped the phase inverter tube from a 12AX7 to a 12AT7. The result is a little more clean headroom with a little less noise.
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Sunday, May 20, 2012

Dayton Hamvention 2012

I went to the Dayton Hamvention on Saturday. Tickets were a steep $25 at the door. My friend Brian landed a BOULEVARD PRINCE for $20. This is a tube powered PA amp from the late '50s or early '60s. As you can see in this photo I got a SHURE SM57 for $10, and a RAMSEY digital multimeter (ohms to 2M!) for another $10. I also bought a pair of 12AT7 tubes. All of these items worked for Brian and I, except for one. I bought a DIRECTV satellite box for $10 knowing it was a gamble. I plugged it in to the satellite dish and it worked, but too well. After it booted up it checked in with the intergallactic command center and then told me that it's registration had expired. In the trash it goes. If you get this update in an email, you can click on the link here and it will take you to the web site where you can enlarge the photo.

Wednesday, April 4, 2012

Rendering the CONN organ

I have been rendering or stripping the CONN organ, recently acquired. There is mouse crap all over the inside of this thing. The speakers are 12", not 15" as previously reported. The upper and lower keyboards are hinged. Under the lower keyboard is a circuit containing roughly 52 of these capacitors. This may be part of the tone generating circuit. I hope to learn the type of contruction for these caps.

Sunday, February 12, 2012

Donor Organ #4

My Dad provided parts from a solid state Lowrey and Hammond, and Ron Ashcroft provided the AO-35 from a Hammond. Friday I retrieved a 1961 Conn model 541 "Minuet" in non-working order. This was listed in the free section of CL. Yes it is a tube job. The amplifier is actually a stereo power amp using two pairs of 7868. These amps go through two crossovers to drive two 15" speakers and a rotating assembly with a Jensen driver. I am thinking about removing this entire assembly complete. The photos show that each key is controlled by half of an 12AU7 and its own tunable transformer.


Friday, January 27, 2012

Champ amp now in cabinet

I finally completed the Fender Champ project. Though the joinery didn't come out like I'd hoped, it turn out well enough. The front baffle was a sliding lid from the 1969 Magnavox console I stripped a couple of years ago.

If you look at the first picture to the right you might think I was way off on centering my handle. The handle isn't centered on the length of the amp, but on the weight. You can see why in the second photo.

In the third photo you can see the aluminum HVAC tape used for RF shielding, as well as the speaker scews used for mounting. The voltage plate came from the Tektronix ocilloscope I've been stripping.

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