Forte Model 5 Transformer Seconday Voltage?
Fellow Earthlings,
My Forte Model 5 appears to have blown it's transformer (zero voltage at the two blue wires from transformer to rectifier). Easy replacement, but I don't know the secondary A/C voltage.
The transformer is an Avel Lindberg Type 40/6217/2 manufactured in 1990
- a search for that netted nothing, and a call to the phone number listed on the AL site got a response from a personal cell phone.
The 1A schematic shows a dual output secondary of 57V, and 36V DC at the boards, but I don't want to depend on that, and of course, M5 schematics are non-existant. And before you mention it, John Soderburg is no longer is business or available.
So, having said all that, does anybody know the secondary voltage, and/or have an M5 you could measure? If you are measuring, please put an insulator over the tops of the PS capacitors and be careful with your probes - that rectifier is all the way at the bottom of the amp.
Thank you!
Fellow Earthlings,
My Forte Model 5 appears to have blown it's transformer (zero voltage at the two blue wires from transformer to rectifier). Easy replacement, but I don't know the secondary A/C voltage.
The transformer is an Avel Lindberg Type 40/6217/2 manufactured in 1990
- a search for that netted nothing, and a call to the phone number listed on the AL site got a response from a personal cell phone.
The 1A schematic shows a dual output secondary of 57V, and 36V DC at the boards, but I don't want to depend on that, and of course, M5 schematics are non-existant. And before you mention it, John Soderburg is no longer is business or available.
So, having said all that, does anybody know the secondary voltage, and/or have an M5 you could measure? If you are measuring, please put an insulator over the tops of the PS capacitors and be careful with your probes - that rectifier is all the way at the bottom of the amp.
Thank you!
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That could be two series 25VAC windings, with a bridge rectifier, which would give +/-35VDC.
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About 58 Volts center tapped should do the the job. That was a custom Avel part and it may have had a thermal cutout in the primary. Unfortunately the cutouts were one time use only.
Thank you, very helpful.
So it sounds like NP used a similar type of power supply (actually, Michael Bladelius, right?) for all of the IGBT amps.
Thanks guys!
So it sounds like NP used a similar type of power supply (actually, Michael Bladelius, right?) for all of the IGBT amps.
Thanks guys!
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I wonder if you guys might help me out a little more in my transformer education here.
1. What wattage rating (heat dissipation?) should I look for in an amp that produces 125 wpc RMS?
2. How important is current output for such an amp? Will this amplifier benefit from 2 amp, 5 amp, 10 amp current capability from the transformer?
3. I've seen the term "Rail Voltage" - is this the transformer output (58VAC), or (as I suspect) the 36VDC from the rectifier to the caps and boards? Or something else?
Thank you again, always appreciate people who help me learn. 😱)
1. What wattage rating (heat dissipation?) should I look for in an amp that produces 125 wpc RMS?
2. How important is current output for such an amp? Will this amplifier benefit from 2 amp, 5 amp, 10 amp current capability from the transformer?
3. I've seen the term "Rail Voltage" - is this the transformer output (58VAC), or (as I suspect) the 36VDC from the rectifier to the caps and boards? Or something else?
Thank you again, always appreciate people who help me learn. 😱)
This begs another question: Using a center tapped transformer, am I looking for the 58VAC between each end of the coil (blue to blue), or 58V from output to center tap?
58 - 0 - 58, or 29 - 0 - 29?
Thank you.🙂
Hey Wayne,
I'm a little concerned. I called a place that lists Forte service to buy a transformer, and the person on the phone said I need 87.5 VAC from the secondary, which translates into 57 VDC at the rail. So now I'm just trying to verify my data before I buy the wrong part (or screw up my amp).
Could you please tell me how you know that the Model 5 transformer secondary is 58V? Or, when you say "About 58 Volts center tapped should do the the job", are you saying 58VDC rail voltage, and in fact we all in agreement?
I know it's a one-in-a-million, but if anybody happens to have a Forte Model 5 on the bench (I don't expect you to take it out of a running system) and could actually measure the secondary AC voltage at the rectifier and let me know, I would certainly appreciate that.
Thanks to all!
I'm a little concerned. I called a place that lists Forte service to buy a transformer, and the person on the phone said I need 87.5 VAC from the secondary, which translates into 57 VDC at the rail. So now I'm just trying to verify my data before I buy the wrong part (or screw up my amp).
Could you please tell me how you know that the Model 5 transformer secondary is 58V? Or, when you say "About 58 Volts center tapped should do the the job", are you saying 58VDC rail voltage, and in fact we all in agreement?
I know it's a one-in-a-million, but if anybody happens to have a Forte Model 5 on the bench (I don't expect you to take it out of a running system) and could actually measure the secondary AC voltage at the rectifier and let me know, I would certainly appreciate that.
Thanks to all!
I'm sitting on one of these courtesy of Nelson and Burning Amp Fest. I checked the voltage and wrote down 46-40-0-40-46V. Do you want it?
Hi Anderson,
Thank you! I guess, as we say, that makes things clear as mud! 😕
I have one person telling me 58 volts, another telling me 87.5 volts, and a transformer of the same part number producing 40 and 48. I feel like I'm just guessing at this point. 🙄
I really like the Forte Model in my system for several reasons, but one of the biggest challenges is this flying blind with no schematics or service information (that I've ever been able to find, anyway).
But I certainly do appreciate you contacting me about this! 😀 What would you like to receive in return for the transformer?
Thank you.
Thank you! I guess, as we say, that makes things clear as mud! 😕
I have one person telling me 58 volts, another telling me 87.5 volts, and a transformer of the same part number producing 40 and 48. I feel like I'm just guessing at this point. 🙄
I really like the Forte Model in my system for several reasons, but one of the biggest challenges is this flying blind with no schematics or service information (that I've ever been able to find, anyway).
But I certainly do appreciate you contacting me about this! 😀 What would you like to receive in return for the transformer?
Thank you.
BTW, I noticed this transformer also has dual primaries. Did you wire the primaries in series or parallel when you took those readings? If you were in series with 40 and 48, parallel (which is the way mine was wired) would produce around 80 and 96v, which at least would be on both sides of the 87.5 the tech mentioned to me.
Using the 48v taps you mentioned, rail voltage in this system would only be about 31VDC, which seems kind of low for an A/B circuit - even heavily biased - when the Model 1 boards run at 36VDC in Class A.
Curiouser and curiouser...
Using the 48v taps you mentioned, rail voltage in this system would only be about 31VDC, which seems kind of low for an A/B circuit - even heavily biased - when the Model 1 boards run at 36VDC in Class A.
Curiouser and curiouser...
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I checked it every which way using 120V input (back then they would have spec'd 110 or 115V), and I'm sure it's the exact same thing you have already, so you came to the right place. I did not load test it, so you'll have to take your chances....
I'll PM you!
I'll PM you!