I love my HeathKit AA-100, I must say and I had a lot of Amplifiers in my life, but this unit makes incredible smooth sound, I also recapped it and I would never sell this angle of sound. I have here Mcintosh , Sonic Frontiers FSF-80, but the good old Heathkit makes the best sound I have ever heard!
I had one of these for a few years. The most striking aspects of it to me were the separate treble and bass controls for each left and right channel, and the control that turned gradually from mono to full stereo. Amazing warm sound too.
I am from Serbia a part of former Yugoslavia. In our language J is pronunced as Y. The factory that produced the tubes was EI (Electronic industry) that was founded after WW2 to produce x ray rubes and radios in the city of Niš (Nish). Until the breakup of Yugoslavia EI even produced tubes, transistors, TVs, stereos and started assembling computers. The tubes were made under Philips license and even today are one of the more expensive tubes.
Yes, I have a 30 year old broom....it's had 5 new heads and 3 new handles....I love my old broom.... :) Quality control on vintage replacement components is left up to the consumer....it's a lot cheaper for the manufacturers that way....
Adding a ground wire to a vintage tube amp can introduce ground loops and noise from associated equipment that is also part of ground system in house. I think the audio community is split on this subject. Myself, I rewire vintage tube amps to use a polarized plug, hot side wire travels through fuse first, then on/off switch. It wont hurt to try a grounded cord if you want, but many who try simply make a mess of things with making the hole bigger to accommodate the larger cord, and there is no strain relief. If amp has a buzz or noise when you plug it in, install a polarized cord instead.
WOW, nice. I built one back in the day when I was 18 after a 5 year string of crystal and SW radio's, test equipment and misc. other small projects. I had it in a 12'x12' bedroom pushing a set of Klipsch K-Horns. I believe that's why my hearing is suffering now and my parents weren't happy either but with those highly efficient speakers and their response the sound was amazing from that amp even at whispering volumes. Never had a problem building it, worked out of the kit no worries. I miss that amp, traded for a McIntosh MC7270 and bought a Hafler pre for my music, maybe I'm just nostalgic about it but I think it was one of the best sounding rigs out there, still have the speakers though.
Thanks for sharing that story! I had no idea how good this amp was until I coupled it with a pair of vintage JBL studio monitors. As a kit, it seemed like an advanced level project. No doubt a lot of fun was had by guys building these back in the day.
Beautiful job once again Mike! You know I bought four of your output boards and I really appreciate the engineering you put into the design. Can’t say enough about all the support you gave during my first rebuild. I will be the first to order whatever you have coming next!
I used to have one of these amps. Talk about a unique design. Unique in aesthetics among hifi gear and to its period of construction. Thanks for the video!
I have one. I put 6gh8 tubes (rewired socket connections) in place of 7199 that I did not have. put a choke input to power supply and 6bx7 tubes triodes (4 each) for low mu triode outputs. sounds great. your restoration sounds great as well. great job.
Hi, I'd like to offer some constructive feedback. As an engineer and audio amp/preamp designer as well as a Ham op since I was 15, 50 years ago, I take exception to what you said regarding not having concerns about powering the unit on without any protective measure. You may get away with that but at some point when you have a completely shorted electrolytic cap just after the rectifier, what may happen is it will briefly draw far more current than the rectifier can deliver resulting in a blown rectifier or worse your HV tap(s) on your power transformer will open. A simple fix is to pull the rectifier out or open one side of a diode bridge if the circuit does not have a tube rectifier. Then check your primary side of the xformer then all of the secondary voltages. If all looks good your transformer is probably OK. However, in case you do have a very low resistance condition with a cap or rectifier it is best to monitor the current as you bring up the AC power with a variac. Just use your multimeter in series in the current mode with one of the input AC lines to measure the current. It will swing high for the first few second while caps are charging after the rectifier is up then go down a good bit. On simple fairly low power tube amp, the initial surge may be over 2 amp then quickly go down to well under an amp..."usually" As you probably know, almost every electronics YT channel doing tube work has had their version of a dim bulb tester.. They were used as far back as the 1930's in radio shops according to some reading I did a few years back when everyone was excited about these simple devices. If you do have something which will rapidly hog what little power coming from a secondary winding, the bulb will act as a ballast and protect the transformer by glowing brightly. Finding transformers for vintage equipment is tough to impossible. Good luck with your restore !!
These are all good points, and I did use a dim bulb in the repair portion of this build. My comment about not needing it for initial power up was specific to this amp because all caps and tubes were coming out anyway, and it wasn't intended to be a general practice. Thanks for watching.
The tubes from Jugoslavia (Yugoslavia) are actually made by Ei factory and licensed by Telefunken West Germany. If they check OK, I suggest you keep them.
I have both the AA-100 and AJ-41 tuner that I restored. I don’t see the point in replacing the original output board if it can be be rebuilt to keep it original as in the one I own. The other issue is the 12AX7 preamp circuit is nonlinear and causes distortion especially at higher gain levels which is easy to correct by replacing it with a 12AT7. This can be seen by looking at a oscilloscope with a sine wave. Now it sounds as good as my Fisher 800C.
The main reason for replacing the output board was because so many of them are mechanically failing. In most cases, the heat from the 7591s have destroyed the substrate, traces were peeling off, and the boards were often cracked. The main reason for fabricating new boards was to extend the life of the AA-100. Of all of the amps that have come through my shop, most of the boards were badly deteriorated. I found one recently that was actually in decent condition but that is rare. The pre-amps on the other hand didn't get roasted and they are usually in good condition.
I'm an Australian guy and we use Brown for active, Blue for Neutral and Green with a yellow stripe for Earth. The choice of these colours I thought was because of Red Green colour blindness. Is this correct and I started writing this without googling it. DUH Cheers Andy from OZ.
In this case I had to induce a failure to find out where the problem was. High voltage arcing can be difficult to trace, and reducing the line voltage would have made the problem go away.
Hello! I've never seen a tone module fail, but I have seen plenty of problems with tube sockets, bad switches, cold solder joints, etc. I would suggest wiggling tubes, poking and prodding circuit boards (with insulated gloves of course!). Eventually you'll find something that gives away the problem.
@@pcbgraphix1903 Thank you. I will continue to look elsewhere. I will scope it out and try and find where the signal on the right side is going weak. Fortunately the left channel is working to compare. Great Vids by the way. I had your output section in my eBay wish list. Are you completely out of them?
@@peterhutchinson3424 You will have fun troubleshooting your amp, especially when you find the culprit! Yes, we're all out of PCBs and there are no plans to build more of them. We're working on an exciting new project which is taking up all of our resources. Watch this space for more information...
Hello, we are no longer doing restorations on the AA-100 amps. We've turned our attention to building new tube amp kits which we hope to have available soon.
Ok I have to say this. You are either single or have a death wish. If my wife walked in and I had an old Zenith radio exploded on the dining room table, I wouldn’t be saying this because I would no longer exist. What did you find causing low output on line level input? Like the presentation! Nice work and sweet amps indeed.
You made a big deal about replacing the power cord with a 3-prong grounded version but then you completely skip over every possible detail about where the new green ground wire should go.
Connect the green ground to the nearest point on your chassis. I used a machine screw and a star washer along with a wing nut and made a nice connection for my turntable ground. I bought four of his boards and they are fantastic. Too bad he won’t be making more of them
I love my HeathKit AA-100, I must say and I had a lot of Amplifiers in my life, but this unit makes incredible smooth sound, I also recapped it and I would never sell this angle of sound. I have here Mcintosh , Sonic Frontiers FSF-80, but the good old Heathkit makes the best sound I have ever heard!
It sure does! Thanks for watching.
Very cool! A video I would recommend to anyone learning best practices.
I had one of these for a few years. The most striking aspects of it to me were the separate treble and bass controls for each left and right channel, and the control that turned gradually from mono to full stereo. Amazing warm sound too.
I am from Serbia a part of former Yugoslavia. In our language J is pronunced as Y. The factory that produced the tubes was EI (Electronic industry) that was founded after WW2 to produce x ray rubes and radios in the city of Niš (Nish). Until the breakup of Yugoslavia EI even produced tubes, transistors, TVs, stereos and started assembling computers. The tubes were made under Philips license and even today are one of the more expensive tubes.
Interesting! I had never seen a Yugoslavian tube before now. Thank you for explaining the "J"!
I grew up on Heathkits, takes me back.
Very cool. Like your choice of Music.
Thanks!
You had me at the resistor statement, can't thank you enough for that.... 👍😊
We all like our amps to be quiet between songs. :-)
Yes, I have a 30 year old broom....it's had 5 new heads and 3 new handles....I love my old broom.... :)
Quality control on vintage replacement components is left up to the consumer....it's a lot cheaper for the manufacturers that way....
What a fantastic job and close attention to detail.
Great video!
Glad you enjoyed it!
Adding a ground wire to a vintage tube amp can introduce ground loops and noise from associated equipment that is also part of ground system in house. I think the audio community is split on this subject. Myself, I rewire vintage tube amps to use a polarized plug, hot side wire travels through fuse first, then on/off switch. It wont hurt to try a grounded cord if you want, but many who try simply make a mess of things with making the hole bigger to accommodate the larger cord, and there is no strain relief. If amp has a buzz or noise when you plug it in, install a polarized cord instead.
I love my AA-100 with your replacement PCB. It really sounds nice.
I'm so glad that you're enjoying the new PCB!
WOW, nice. I built one back in the day when I was 18 after a 5 year string of crystal and SW radio's, test equipment and misc. other small projects. I had it in a 12'x12' bedroom pushing a set of Klipsch K-Horns. I believe that's why my hearing is suffering now and my parents weren't happy either but with those highly efficient speakers and their response the sound was amazing from that amp even at whispering volumes. Never had a problem building it, worked out of the kit no worries. I miss that amp, traded for a McIntosh MC7270 and bought a Hafler pre for my music, maybe I'm just nostalgic about it but I think it was one of the best sounding rigs out there, still have the speakers though.
Thanks for sharing that story! I had no idea how good this amp was until I coupled it with a pair of vintage JBL studio monitors. As a kit, it seemed like an advanced level project. No doubt a lot of fun was had by guys building these back in the day.
Beautiful job once again Mike! You know I bought four of your output boards and I really appreciate the engineering you put into the design. Can’t say enough about all the support you gave during my first rebuild. I will be the first to order whatever you have coming next!
I had a question on the music that playing on your turntable and sample at the end, what was the name of it please.
Awesome, thank you!
Just One More Chance by Norman Percival.
excellent work sir. Thanks for sharing all the tips!
My pleasure!
I’m looking forward to what you have in store.
I used to have one of these amps. Talk about a unique design. Unique in aesthetics among hifi gear and to its period of construction. Thanks for the video!
used to ? not anymore ?
I have one. I put 6gh8 tubes (rewired socket connections) in place of 7199 that I did not have. put a choke input to power supply and 6bx7 tubes triodes (4 each) for low mu triode outputs. sounds great. your restoration sounds great as well. great job.
It looks really good🎉🎉🎉resistors😅😅😅 I got rid of it in my high pass filter😂😂😂
A step drill bit works best for enlarging an existing hole.
I've invested in one. You're right, it goes fast!
I just completed the restoration of a similar AA100. Beautifully sounding amp.
The old engineers did something right!
Hi,
I'd like to offer some constructive feedback. As an engineer and audio amp/preamp designer as well as a Ham op since I was 15, 50 years ago, I take exception to what you said regarding not having concerns about powering the unit on without any protective measure. You may get away with that but at some point when you have a completely shorted electrolytic cap just after the rectifier, what may happen is it will briefly draw far more current than the rectifier can deliver resulting in a blown rectifier or worse your HV tap(s) on your power transformer will open.
A simple fix is to pull the rectifier out or open one side of a diode bridge if the circuit does not have a tube rectifier.
Then check your primary side of the xformer then all of the secondary voltages. If all looks good your transformer is probably OK.
However, in case you do have a very low resistance condition with a cap or rectifier it is best to monitor the current as you bring up the AC power with a variac. Just use your multimeter in series in the current mode with one of the input AC lines to measure the current. It will swing high for the first few second while caps are charging after the rectifier is up then go down a good bit. On simple fairly low power tube amp, the initial surge may be over 2 amp then quickly go down to well under an amp..."usually"
As you probably know, almost every electronics YT channel doing tube work has had their version of a dim bulb tester.. They were used as far back as the 1930's in radio shops according to some reading I did a few years back when everyone was excited about these simple devices.
If you do have something which will rapidly hog what little power coming from a secondary winding, the bulb will act as a ballast and protect the transformer by glowing brightly.
Finding transformers for vintage equipment is tough to impossible.
Good luck with your restore !!
These are all good points, and I did use a dim bulb in the repair portion of this build. My comment about not needing it for initial power up was specific to this amp because all caps and tubes were coming out anyway, and it wasn't intended to be a general practice. Thanks for watching.
The tubes from Jugoslavia (Yugoslavia) are actually made by Ei factory and licensed by Telefunken West Germany. If they check OK, I suggest you keep them.
They were pretty well shot so the owner asked for a full re-tube.
I have both the AA-100 and AJ-41 tuner that I restored. I don’t see the point in replacing the original output board if it can be be rebuilt to keep it original as in the one I own. The other issue is the 12AX7 preamp circuit is nonlinear and causes distortion especially at higher gain levels which is easy to correct by replacing it with a 12AT7. This can be seen by looking at a oscilloscope with a sine wave. Now it sounds as good as my Fisher 800C.
The main reason for replacing the output board was because so many of them are mechanically failing. In most cases, the heat from the 7591s have destroyed the substrate, traces were peeling off, and the boards were often cracked. The main reason for fabricating new boards was to extend the life of the AA-100. Of all of the amps that have come through my shop, most of the boards were badly deteriorated. I found one recently that was actually in decent condition but that is rare. The pre-amps on the other hand didn't get roasted and they are usually in good condition.
iirc Jugoslavia was how Yugoslavia was spelt in the country itself, the rest of the world called it Yugoslavia
I'm an Australian guy and we use Brown for active, Blue for Neutral and Green with a yellow stripe for Earth. The choice of these colours I thought was because of Red Green colour blindness. Is this correct and I started writing this without googling it. DUH Cheers Andy from OZ.
Yes, Jugoslavia can indeed be spelt that way. Not everybody is American ;)
A friend has one of these, what could cause voltage present on the metal chassis? touching the chrome bezel gives you a tingle when turned on..
There's some kind of electrical fault inside it. Try turning the power cord over in the outlet.
how about using a variac to test your rebuild instead of changing blown fuses?
In this case I had to induce a failure to find out where the problem was. High voltage arcing can be difficult to trace, and reducing the line voltage would have made the problem go away.
What was the music at the end of the video? I'm a vintage music buff.
Just One More Chance by Norman Percival.
Hello.
I have one that has an intermittent right channel.
Do those tone control modules ever fail?
Hello! I've never seen a tone module fail, but I have seen plenty of problems with tube sockets, bad switches, cold solder joints, etc. I would suggest wiggling tubes, poking and prodding circuit boards (with insulated gloves of course!). Eventually you'll find something that gives away the problem.
@@pcbgraphix1903 Thank you. I will continue to look elsewhere.
I will scope it out and try and find where the signal on the right side is going weak. Fortunately the left channel is working to compare.
Great Vids by the way.
I had your output section in my eBay wish list.
Are you completely out of them?
@@peterhutchinson3424 You will have fun troubleshooting your amp, especially when you find the culprit! Yes, we're all out of PCBs and there are no plans to build more of them. We're working on an exciting new project which is taking up all of our resources. Watch this space for more information...
ua-cam.com/users/shortsALAVO0w3eOo?feature=shared
Thanks Mike.
Hi! Do you still do restorations on the aa-100 ? I’m currently looking for someone that knows these particular unit please let me know thank you.😊
Hello, we are no longer doing restorations on the AA-100 amps. We've turned our attention to building new tube amp kits which we hope to have available soon.
@@pcbgraphix1903 OK are the circuit boards are going to be readable available or are they gonna be discontinued to
@@zacharystrohl5566 The AA-100 circuit boards are discontinued and sold out.
Ok I have to say this. You are either single or have a death wish. If my wife walked in and I had an old Zenith radio exploded on the dining room table, I wouldn’t be saying this because I would no longer exist. What did you find causing low output on line level input? Like the presentation! Nice work and sweet amps indeed.
No worries...We use another table for eating at.
Yes, the low level was caused by my phone's volume to revert back to low level. That was an easy fix.
You made a big deal about replacing the power cord with a 3-prong grounded version but then you completely skip over every possible detail about where the new green ground wire should go.
Connect the green ground to the nearest point on your chassis. I used a machine screw and a star washer along with a wing nut and made a nice connection for my turntable ground. I bought four of his boards and they are fantastic. Too bad he won’t be making more of them
Thank you sir!@@Retroelectroworkshop
Great Job