Posts: 264
Threads: 51
Joined: Aug 2014
City: San Antonio, TX
I've had a really nice wooden Crosley 66TC cabinet for quite a while with a trashed chassis to go with it. For about a year, I looked for a replacement, and finally found a 66CS (the console version with phono). They are almost identical as far as chassis size and electronics (same tube lineup, same power filter circuit, same tuning cap, etc.), but the speaker on the CS is 10" and the one for the TC is about 5". I fired up the Crosley 66CS tonight for the first time, and it is a great performer. Broadcast AND shortwave worked great. A nice lady in China was telling me things for a while. I put together a makeshift loop for it that I had a different thread about, and it picks up stations all across the dial, but I intend to order the repro back and mount a permanent loop on there.
These speakers are dynamic speakers, right? The one the chassis came with is too large to go in my 66TC cabinet, but I have that speaker that will fit (it came with the trashed chassis). The problem is that the field coil measures about 200 ohms less than the field coil on the 10" speaker that came with the chassis. Can you think of any reason why I couldn’t just swap the FCs on the speakers? The voice coils both measure basically zero. Or would it be better to make up the difference for the circuit with a resistor?
Here are the two pertinent schematics:
The Crosley 66CS (s) look at the one with the 40uf filter cap in addition to the 3 20uf:
http://www.nostalgiaair.org/pagesbymodel...003572.pdf
The Crosley 66 TC:
http://www.nostalgiaair.org/pagesbymodel...003576.pdf
Charlie in San Antonio
Posts: 7,212
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Joined: Dec 2009
City: Roslyn Pa
Hey Charlie,
Is it hot down there???
The resistive difference between the FC isn't going to matter much. At best wire it up and it will work fine at worst you may incur a bit of hum that can be rectified by add some more mfds to the power supply. You are better off not replacing the FC with a resistor as a resistor has no inductance to speak of. Spkrs with a FC are dynamic spkrs w/o a FC are PM (permanent magnet)
Terry
(This post was last modified: 08-10-2015, 06:15 AM by
Radioroslyn.)
Posts: 264
Threads: 51
Joined: Aug 2014
City: San Antonio, TX
Two weeks now with highs over 100 degrees. Nah. It makes me think about moving to Colorado more and more. I'll try the switch today, and see what happens. I'm amazed at how good this little radio is, though. That little loop antenna, and it brings in ALL the stations.
Charlie in San Antonio
Posts: 264
Threads: 51
Joined: Aug 2014
City: San Antonio, TX
I gave it a try, and it works alright, but the smaller speaker maxes out way before the volume control is maxed out. I'm wrong about the speakers, though. They seem to be old PM with output transformers mounted on them. The measurement across the magnet is about zero on both speakers.
The 10" speakers transformer is around 450 ohms while the 5' speaker's is about 240 ohms. Looking at the tube data sheet for the output tube (a single 6v6GT), it looks like I could get a newer 4 ohm PM speaker and run it through the larger output transformer, or would an 8 ohm speaker work? Assuming the plate voltage is not over 250v. One of the problems with the smaller speaker is an old cone repair that has more repair paper visible than original cone (it looks like coffee filter paper) and shiny glue all over.
I guess I COULD try to recone the smaller one with one of these? Cut it all away except for a half inch or so around the spider and use diluted fabric glue to attach the new cone? I've never done it before, but it might work.
http://www.electronix.com/advanced_searc...ne&x=0&y=0
Charlie in San Antonio
Posts: 19
Threads: 9
Joined: Feb 2010
City: Galesburg Il.
(08-09-2015, 11:42 PM)ccomer1955 Wrote: I've had a really nice wooden Crosley 66TC cabinet for quite a while with a trashed chassis to go with it. For about a year, I looked for a replacement, and finally found a 66CS (the console version with phono). They are almost identical as far as chassis size and electronics (same tube lineup, same power filter circuit, same tuning cap, etc.), but the speaker on the CS is 10" and the one for the TC is about 5". I fired up the Crosley 66CS tonight for the first time, and it is a great performer. Broadcast AND shortwave worked great. A nice lady in China was telling me things for a while. I put together a makeshift loop for it that I had a different thread about, and it picks up stations all across the dial, but I intend to order the repro back and mount a permanent loop on there.
These speakers are dynamic speakers, right? The one the chassis came with is too large to go in my 66TC cabinet, but I have that speaker that will fit (it came with the trashed chassis). The problem is that the field coil measures about 200 ohms less than the field coil on the 10" speaker that came with the chassis. Can you think of any reason why I couldn’t just swap the FCs on the speakers? The voice coils both measure basically zero. Or would it be better to make up the difference for the circuit with a resistor?
Here are the two pertinent schematics:
The Crosley 66CS (s) look at the one with the 40uf filter cap in addition to the 3 20uf: http://www.nostalgiaair.org/pagesbymodel...003572.pdf
The Crosley 66 TC: http://www.nostalgiaair.org/pagesbymodel...003576.pdf
On the 2nd IF output there appears to be a ground and a connection from the tuning cap to the junction of the 47 k and 2.2meg. What is this wire for, in chassis it has a wire cover and one end of cover is grounded. and are both ends of this wire connected?
Posts: 264
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Joined: Aug 2014
City: San Antonio, TX
That wire cover looks like a spring? If it does, then it is shielding, and the shielding is grounded to the chassis somewhere. You can find the lead inside the shielding running between the IF's padder and the junction of those two resistors. It looks to me. Others can correct me if I'm wrong on that. I'll try to look at one of my 66 chassis tomorrow to verify.
Charlie in San Antonio
