H.H. Scott 222c Integrated Amplifier

Hey Biggs,

Looks like you're almost ready to fire this baby up!
Get some pics up when she's all a glow and beautiful!

Glenn
 
Thanks mang! Luckily, I've purchased most all the tubes I need from Barter Town, feeling good about it. I think all I need now are the 7199's. Then a nice test and go from there. Yeah, I can hardly wait too.

Biggles
 
njcanuck said:
Lk-48s are basically the same as 222s as well. I did a restoration thread on one of those a while back. Your schematic is probably in the AK database.

I've restored three of these Scotts todate, so FWIW here is the approach that I would suggest:

1. Fill it up with tubes and make sure it works. If it doesn't, fix it before doing anything else. Nothing is more confusing than trying to restore an amp that doesn't work! Then perform the restore in small stages, testing after each stage to make sure it still works. It's much easier to find errors this way.

2. Install 10 ohm bias sensing resistors, tip jacks (and optionally, additional bias pots) on the output tubes so that you can see what the tubes are doing at each step of the process. Test.

3. Replace the selenium rectifier and bias supply caps (remember that the can cap is common positive). Test.

4. Replace the power supply caps. Test.

5. Replace the power tube coupling caps. Test.

6. Replace the inverter tube coupling caps. Test.

7. Replace the signal tube coupling caps. Test.

8. Replace any other misc electrolytic caps under the chassis. Test.

9. Replace the phono section caps and loudness control caps. Test.

10. Lastly, replace the front panel caps if you think it's necessary. Most of these see very little voltage and are probably fine. Test.

There's probably a few other bits that I missed but you get the general idea.

Have fun! It'll be well worth it.
Click to expand...

11. Relieve front end of frequency limiting devices. :para:
 
Tap tap, is this thing on? Anyone listening?

Hi!

Uh, I need a little help. Soon after my last post here back in June, I sent this rig off to NOS Valves for their full monty. I realized that I'm more of a speaker guy and not so much a vacuum tube restoration guy. All was fine.

QUESTION #1

I've used it off and on over the past months.

It was working fine earlier today.

But now, the switches (loudness and rumble filter) are scratchy. And by scratchy I mean there's no way to quiet them down. You can wiggle them and change how the scratchiness sounds. But it's just spewing forth loud scratchy in a continuous flow.

I've done some reading on here and it's mentioned that these switches are considered to be Deoxit Immune. So, these people will bypass them. Then, it's highly recommended to not bypass them because it creates other problems. If done correctly, all should perform as expected.

QUESTION #2

Am also now getting large volumes of hum when the amp is turned to Phono. Turntable is grounded and sounded fine previously. The hum is so bad you cannot listen to music at any level. Only when I adjust the bass control knobs all the way to the left does the rumble go away.

I would take it in for service back to NOS, but income has gone away, again. So, the 100 dollar round trip via UPS is not an option.

Does anyone have any thoughts?

xo, Biggles
 
Try this

Hi biggles,
I've restored several Scott's and grew up with an original one (299C) and have not witnessed the scratchy switches as you are describing them. I do use De'Oxit as well. Scratchiness is caused by poof connections between switch contacts, or the small arcs that occur before the switch is at its final position. Try setting the switch to whatever listening position you were in when you heard the scratchiness then press on the switch to see if the scratchiness goes away. If it does, you may have worn out switches or badly oxidized switches.

Sometimes the moving a switch can reveal a weakness in some other part of the circuitry, like a loose tube, poor solder joint, or a leaky (out of spec) capacitor.

For the turntable Hum this is common and is usually caused by a poor connection of your RCA cables to the phono input jacks. If the outer shield contacts do not make a good connection with the jack, you will have tremendous hum. This can also happen back at the turntable if you wires are also plugged into jacks there. Also check that you cartridge wiring is sound and you have a good, low resistance ground wire connection.

Good luck!
 
getter365 said:
Hi biggles,
I've restored several Scott's and grew up with an original one (299C) and have not witnessed the scratchy switches as you are describing them. I do use De'Oxit as well. Scratchiness is caused by poof connections between switch contacts, or the small arcs that occur before the switch is at its final position. Try setting the switch to whatever listening position you were in when you heard the scratchiness then press on the switch to see if the scratchiness goes away. If it does, you may have worn out switches or badly oxidized switches.

Sometimes the moving a switch can reveal a weakness in some other part of the circuitry, like a loose tube, poor solder joint, or a leaky (out of spec) capacitor.

For the turntable Hum this is common and is usually caused by a poor connection of your RCA cables to the phono input jacks. If the outer shield contacts do not make a good connection with the jack, you will have tremendous hum. This can also happen back at the turntable if you wires are also plugged into jacks there. Also check that you cartridge wiring is sound and you have a good, low resistance ground wire connection.

Good luck!
Click to expand...

Hey Getter,

Oooo ooo. Yeah, the RCA cable solution sounds like a good one. I like that, will clean contacts on both the amp and turntable. I'll check the cartridge too, excellent.

The capacitors in the amplifier should have all been replaced, but this is not confirmed by my eyeballs.

There's no way to set, or move the switches to get the scratchiness to go away. It's a solid, spew of scratch in any position. I have gently moved the switches repeatedly to work them a bit, no change.

Am planning on dragging the unit into the garage tomorrow morning and giving them a good deoxit. I will also wiggle and use a magnifying glass to see if I can find anything loose, something that might be the culprit.

Thank you so much!

Biggles
 
Also try to bend in slightly the outer contacts on the RCA cables so they "grab" the phono input jacks better. Not too much or they won't slide on. I read a long time ago that the outer diameter of the Jacks on some vintage equipment is smaller than that of today's standards. I never actually measured to confirm this. But that can be a problem. Always seem to get that hum on the phono input if and when it happens. Never on the line level inputs.

Wish I could help more with the slide switch issue, but maybe a cleaning might do the trick. Did you state what slide switch is causing the scratchiness. I never owned a 222 but I know a bit about them.

Hope you can solve this.
 
getter365 said:
Also try to bend in slightly the outer contacts on the RCA cables so they "grab" the phono input jacks better. Not too much or they won't slide on. I read a long time ago that the outer diameter of the Jacks on some vintage equipment is smaller than that of today's standards. I never actually measured to confirm this. But that can be a problem. Always seem to get that hum on the phono input if and when it happens. Never on the line level inputs.

Wish I could help more with the slide switch issue, but maybe a cleaning might do the trick. Did you state what slide switch is causing the scratchiness. I never owned a 222 but I know a bit about them.

Hope you can solve this.
Click to expand...

OH, it'll get solved one way or another. I'm over 600 bux into this amp, there's no going back now. I would agree about the smaller diameter of the RCA inputs, from my personal experience. But I haven't used something this old in a long, long time.

The faceplate on my 222 is very very very worn, the letters are barely legible, if they're there at all. And, I haven't been able to find a users manual for the 222c. I've found one for the 222d. I'm sure one of the switches is the Loudness, far right. And the other one is the one on the FAR left, I can barely make out EQUALIZATION. But what it says to the right and left of the switch is unclear.

Biggles
 
That really stinks Big's. I was wondering if a call to NOS Valves might help your situation. I am sure that you paid them a decent price to work on it the first time, and I would think that they would provide you with some good information that may help you to fix it. Good luck!
 
doctorolds said:
That really stinks Big's. I was wondering if a call to NOS Valves might help your situation. I am sure that you paid them a decent price to work on it the first time, and I would think that they would provide you with some good information that may help you to fix it. Good luck!
Click to expand...

Thank you! The amp hails from 1961, it's old. Whether it's been rebuilt or not, it's going to have its own personality. At least that's how I look at it. I will contact Craig shortly and see if he has any input. Given the time of year, I was going to give him a few days of rest before I rattled his cage, so to speak.

Again, it's a 100 dollar round trip. I need to take care of any further issues myself, or find an affordable tech in this area. These issues don't sound too terribly bad.

With a wool sweater on, fingerless wool gloves in place, I got the amp out into the garage. I took the cover off that houses the tone controls.

I can see 2 capacitors that were swapped out, am guessing the little originals in there were within spec. I do know that many will leave these in place, so I'm okay with it. It wouldn't take much to install new ones in their place.

I used the deoxit on the switches and pots. I didn't get any noticeable googe out of them, so there's that.

The shielding for the inputs on the back were DIRTY !!!!!!!! They're not pretty, but they're cleaned up now and without any residue.

I'll hook it back up later today and see what, if any differences there are. I'm going to say that any issues I had yesterday are gone.

Scot222c010.jpg


Scot222c011.jpg


Biggles
 
Biggles, just emailed you a photo of my 222c's face plate, a copy of a manual and some schematic info.
 
nhparrot said:
Biggles, just emailed you a photo of my 222c's face plate, a copy of a manual and some schematic info.
Click to expand...

Hasn't arrived yet, but I would imagine it takes more than 3 milliseconds.

I buttoned the unit up and drug it back inside. The constant scratchiness from the switches is gone. Bam.

The audible/annoying hum from the turntable is still present. I have not messed with the cartridge yet.

I disconnected the TT from the amp and the amp went silent, even with the volume turned up. Am guessing the culprit is the TT.

If something is amiss there and I am unable to sleuth it out, will start up a thread in the appropriate forum!

Biggles
 
Buuut, the TT is quiet on my other SS amps. The hum sounds like old tubey hum. I wonder if the phono portion of the amp's circuit is grumpy, prolly that.

Biggles
 
doctorolds said:
Check it with another TT if you have one handy.
Click to expand...

My other one has a dead channel. It might be helpful even in that condition, just to see.

I think I'm going to head off to see what nature has in store today. It's brisk today, but sunny and somewhat warm in the sunny portions.

I've got LP's spread all over the living room this morning, weeding out the sick and reorganizing. Yeah!

Biggles
 
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