You might look at this Hammond toroidal; it's a lower VA than what I used, but physically smaller.
I know you said you may not be up to the mechanical aspects of making a bracket, but it may be an option if you want to give it a try.
https://www.hammfg.com/files/parts/pdf/1182F18.pdf
I know you said you may not be up to the mechanical aspects of making a bracket, but it may be an option if you want to give it a try.
https://www.hammfg.com/files/parts/pdf/1182F18.pdf
HEllo,
I do not know what is the situation on the other side of the pond, but in France I can still find people willing to make a transformer for me with the specifications I want. Of course, a special fabrication may not come cheap but you have a thing of beauty vacuum impregnated with bells and the length of wire you want...
For example look at Electra Sud-Ouest the web site is not the best I've seen but if you need output transformer for a valve tube ask them ! (I do not have any financial relation with them but a very satisfied customer).
Hope this will help.
I do not know what is the situation on the other side of the pond, but in France I can still find people willing to make a transformer for me with the specifications I want. Of course, a special fabrication may not come cheap but you have a thing of beauty vacuum impregnated with bells and the length of wire you want...
For example look at Electra Sud-Ouest the web site is not the best I've seen but if you need output transformer for a valve tube ask them ! (I do not have any financial relation with them but a very satisfied customer).
Hope this will help.
Hello,
I've ordered some 10µF capacitors and the caps in the power supply. Alas the sender made a mistake and send me bipolar caps for the 10µF. He acknowledged it's error but in order to have the proper one shipped I must return the others. This will make a set of 10 caps expensive.
Question : Could I use bipolar instead of polarized ones ? Knowing that they are everywhere and not only in the signal path ?
Thanks for your answer.
I've ordered some 10µF capacitors and the caps in the power supply. Alas the sender made a mistake and send me bipolar caps for the 10µF. He acknowledged it's error but in order to have the proper one shipped I must return the others. This will make a set of 10 caps expensive.
Question : Could I use bipolar instead of polarized ones ? Knowing that they are everywhere and not only in the signal path ?
Thanks for your answer.
For the power supply you must use polarized electro caps-also I would suggest you use 22uf Nichicon PW, and the main 1000ud - I would upgrade to 2200uf - either Nichicon PW or HE. so do not use bi-polar in the power supply
I have an Apt/Holman preamp where I lost one channel, cause was IC7. I replaced it and all of the electrolytic capacitors, worked great for a week. Then I lost one channel in the phono section, Q1 & Q3 were bad, I replaced them it lasted about a couple of days before another channel went out. This time IC4 was bad, during testing, I kept getting voltages inconsistent with the manual.
I pulled the transformer out of the unit, (secondaries cut from PCB), and tested the transformer. I'm getting 57 vac going to the rectifier. I have 18vdc at the rear panel which has an RCA type jack for 18vdc, the LED works, yet I'm getting 30 - 31 vdc out of the rectifier.
I'm thinking the transformer has to much voltage on the secondaries causing the IC's and transistors to pop.
GTKAUDIO is recommending 18v secondaries for a replacement.
Why are my voltages so far off?
I pulled the transformer out of the unit, (secondaries cut from PCB), and tested the transformer. I'm getting 57 vac going to the rectifier. I have 18vdc at the rear panel which has an RCA type jack for 18vdc, the LED works, yet I'm getting 30 - 31 vdc out of the rectifier.
I'm thinking the transformer has to much voltage on the secondaries causing the IC's and transistors to pop.
GTKAUDIO is recommending 18v secondaries for a replacement.
Why are my voltages so far off?
Attachments
Did you test across both secondaries, or from one secondary to center tap, then the other? Unloaded, the reading was 57VAC? That is too high. I did some unloaded tests on a couple of these transformers, but I can't recall the voltages and my notes aren't handy.
If you are getting +18VDC off the back jack, the positive regulator appears to be working properly. Which regulator were you getting 30-31VDC from - positive or negative? Is the bridge functioning properly? Filter caps good?
If you are getting +18VDC off the back jack, the positive regulator appears to be working properly. Which regulator were you getting 30-31VDC from - positive or negative? Is the bridge functioning properly? Filter caps good?
Sounds like someone's measuring the voltage improperly by miswiring the transformer.
It must be wired for 120V, and consider the dual secondary windings.
It must be wired for 120V, and consider the dual secondary windings.
I'm going to replace the transformer, diode bridge and negative side regulator.. The caps are new Audio Note Gold
I suggest doing one thing at a time. First make sure you have measured the transformer output correctly. If you've confirmed it is way out of spec, sub in a different one. My experience with bad transformers is that they put out less voltage, particularly under load, not more, when they have suffered some damage to the windings.
Test the negative regulator, rather than first replacing it. Test the bridge, or sub in one, tacked to the transformer wires outside the chassis, then test the voltage coming out of the bridge before connecting it to the voltage regulator.
It is always better to nail down the problem, rather than shotgunning.
Test the negative regulator, rather than first replacing it. Test the bridge, or sub in one, tacked to the transformer wires outside the chassis, then test the voltage coming out of the bridge before connecting it to the voltage regulator.
It is always better to nail down the problem, rather than shotgunning.
adding to to GKT advice- step by step will resolve the issues. The 78/79 series regulators do get noisy in these units with time, so new ones will assist. The diode bridge can be upgraded to a 1.5amp version (WO6), and I would suggest for the power supply you really want low impedance caps (Nichicon PW/HE)- and bring the main ones up to 2200uf from 1000uf- with the smaller ones form 10uf to 22uf. I recently replaced a transformer in one of these (with the assistance of GTK!) - Triad VPS36-700- alternatively a talema group toroidal 70064K can be fitted with a little metal working.