Papajoe

Hi Greg, Long time between conversations. Would it be possible to have a section on the site dedicated to listing the components that are needed for DIY refurbishment of each model? I realize that some models are pretty complex, for a casual rebuild. Longtime members like you, usually have some models, if asked. Maybe everyone can share their lists and put them in a specific section for all to use? Thanks, Papajoe

A rule that I always go by is " for every pair of speakers that I buy, I need to have a system to power them". That helps to keep down the 'want to buy more speakers' to a minimum. Papajoe

Brian D. I read your post and thought to myself 'Compression'. You know, I cannot ever remember hearing that term used in terms of 'vinyl' . It seems to me that the 'term' was first used in regards to digital recordings because of the large size of the sound files and the restraints of the recording 'medium' being used. Papajoe

Wizard.

Happy trails- I will second that.

Zumbini- You are correct about the wrong amp. When I first went to his house and started talking to him about I thought was a possible conflict with his amp, he looked at me and said "I am going to use the TFM-15 not the TFM-25. Then I remembered that I had also sold him a TFM-15 to use just for this purpose. Boy, did I feel 'dumb'. LOL Papajoe

Maybe, I did not put that correctly. He will be using the 'A' speaker outputs on the amp to run his outdoor speakers. Saving the 'B' output for a second pair of speakers, later.

Well, I finally got the info on that 'switch'. It's an Audiosource AE100VC. It is an 'Impedance matching volume control'. It is used to allow you to run up to 16 '8' ohm speakers off of one channel of an amp without overloading the amp. It has a slide switch that allows you to choose 1x, 2x, 4x and 8x, depending on how many speakers you have. I believe that it presents a 4 ohm load to the amp. It also has a master volume control included. He will be running 2 pairs of 8 ohm speakers. The A,B, A+B switch is just that. He is using one channel of his TFM 15 amp to run these outdoor speakers. The other channel will be used to run a wireless speaker set into his shop. The whole thing will be controlled by the 'second zone' on his CT-17 preamp. Doesn't sound that confusing anymore. Papajoe

Hey, I'm a pure bred Italian, we do some of our best planning with a 'wine' catalyst. Papajoe

Sorry about all the confusion. I am confused myself and if I am confused that is not a good thing. My neighbor and I talked about this during one of our 'after 5 PM meetings' and you know what that means 'wine' will be present. More about this later. We need at least one more 'meeting' for clarification. Papajoe

He is wanting to have each location running stereo. I will find out about the switch. Papajoe

Hi All, My neighbor is going to use one channel of his TFM-25 to drive two sets of outdoor speakers. He can't use both channels due to a physical problem. He only ran 1 set of wires from the amp position to the switch area when wiring his house. So, he will try to accomplish this by feeding one channel of the amp to a splitter switch that has some sort of amplifier built in . (I have not seen the unit.) Its one of those 'A', 'B' and 'A' plus 'B' ones. Will he need to use 16 ohm speakers outside,so that when he chooses 'both' he doesn't overload the amp? I seem to remember something about speakers in parallel. Thanks, Papajoe

Welcome to the group. Papajoe

Welcome David.

Morris- Thanks for taking the time to get into your NASA TFM-42 and sending photos. Your schematic helps me to understand what was done and how it works. Do you think that was done by NASA or did Carver specially modify the amps for them? I did look at the connections when I first got the amp; but, do not understand enough to tell where they go on the board. I located ,on the web, of course, the original tech booklet that was put out by Thiel when they first introduced the CS 3.6s. It states that the speakers are rated at 100-500W @4 Ohms. So, we have decided to not do anything to the TFM-42's output after all. Just hook them up and listen to the Carver magic. Papajoe

WRF- thanks for the info that everything is going OK after the crossover and driver rebuild. We have been trying to figure out what to do with all the power and the Thiels? I thought of using the 'NASA' TFM-42, which has Carver installed volume pots, to keep the power under control. We will see. We will be having the crossovers rebuilt by Thiel and I will attach a photo of what they have done, when they get back. As many of you have noted, that crossover board is just too crowded. It is interesting to me that the woofer and tweeter share the same board. Easy route to disaster? After removing the boards from the cabinet, that was the first thing that struck me, why so packed together? There is lots of room in that cabinet to spread the components out or add additional boards. Even my wife, who has seen only a few crossovers, said "Didn't they realized that putting them so close together was going to cause a problem?" Papajoe

Belvedere2- I never would have believed that I would have ever, ever said that; but, those Thiel CS 3.6's, of my neighbor, have me asking that. (Shudder, Shudder) UncleMeat- I was lucky enough to be one of the member who got in on that deal and still have that amp. In the back of my mind, I have been wondering if that would work in this case. I am glad that I asked that question. When I got that amp, I opened the case to see how those pots were used. I thought that they had been just placed in the input signal like the TFM-15s. But no, they are connected directly onto a circuit board in the amp. I guess that Carver added them specifically for NASA's needs. The amp just needs to be refurbished. Papajoe

This is where I need the input from the more electronically knowledgeable member than me.(Just a newbie). Is there any way to limit the TFM-42 from putting out 600W@4 Ohms? Can we lower the total input signal on the amp? Just not feeding enough input for the amp to reach 600 W? Would that have any influence on the performance of the amp? Of course, simply answer, keep the volume down. Papajoe

Thanks Dav-Em. I read that article also and find it interesting stuff. Papajoe

After scratching my head, I realized that the TFM-25 would be a great match. 225w@8 Ohms and 350W at 4 Ohms. Actually, that is the amp that he was using when I said "Why aren't you using your TFM-42"? Papajoe

The TFM-42 was recently refurbished by the previous owner, so that is not a contention. After doing more research, I have found that the Thiels are rated 300-500W, but at 4 OHMs. The TFM-42 can easily drive loads at 4 Ohms; but, the fact is that it will be putting out much higher wattage than the speakers can handle. It is also a know fact that the Thiels are power hungry. Putting more need to "turn it up". Time to find another amp to power those beasts. Papajoe

Wayne, Thanks for taking the time to explain the technical end of my problem. The photos were the icing on the cake. We will be removing the drivers and crossovers and sending them to Thiel service to be evaluated. Thiel service had rebuilt those same drivers. If he finds that a failing crossover, which should been serviced last time, was at fault, he will rebuild them again for free. He will also rebuild the crossovers as Wayne did. More about this after the removal. Papajoe

Up to this point, I have been one of the people who has thought that our beloved Carver amps can power any speaker. But, what has made me question that belief is a pair of Thiel speakers that run in the 2-4 Ohm range. They are noted to be very power hungry and only will be at their best when they are supplied by the proper amp. The amp in question is a TFM 42. Plenty of power and rated in the 4 Ohm range. But, is it the proper one to power those speakers? What do you think? Papajoe

Yes, he did and thanks for the info. I am glad that a member of the original Thiel family took up the reigns on repairing the speakers. Kind of reminds me about Rita at Carver. Papajoe

Hi WRF, I see that you read my previous post. The dealer is blaming the amp as the cause of the damage. He is running a TFM 42 with a Carver CT 17 pre. I have added more info on my post. Could you, please, send me the name and phone # of the Thiel service center. I have read on the web that the damaged tweeter and midrange was a common occurence. Thanks, Papajoe