Ok . . . Picked up an H H Scott 299(a)

[Plimpington2]

UHG!!! That title should say HH Scott.


Ok, back to work. I’m recently back from my local audio emporium and picked up a very nice (cosmetically) Scott 299(a). I believe this is a second generation 299, right before the (b), so uses 7189’s at the output. Just HUGE iron.

Anyway, here’s the front - looks pretty good. I’d rate it at 80%. A bit of roughness on the far right. In a nice wood case. No worries at all. Pots and switches feel very nice. Funny, the balance is detented. The volume is not.

Here’s the viscera. As you can see it’s been molested!!

Some funny business on the far left where the electrolytic cans are. We’ll see more later.

These resisters have been cut and are flapping freely in the wind!!!!! Those yellow caps are not original. I can probably use those. But look at what is going on below!! Someone broke the brown composite mount and kinda “hot glued” a big electrolytic down. Fortunately, that’s the only broken mount. These blue things should have been multi-section metal cans.

The rest of the topside looks ok. BIG iron for this little amp, I think.

Some more cut wires here on this switch. ‍‍‍

Here some axial Electrolytics have been soldered in in lieu of replacing the cans (this am has a lot of multi-section cans), and hidden under good old fashioned electrical tape.

And what these two Electrolytics are doing hot glued to the back of case case here, I have no idea. They are wired in series and sit between the cathode of one output tube and ground. They are both 80uf.

Uhg, and these original caps are BURRIED between the plates of this switch. That’s not gonna be fun.

SN 14304.

I’m guessing this is TOO much for my first Integrated project. Will require going through with fine toothed comb with the schematic. Not sure at all if I can do it. That underside is dense!!!

I also happened to pics up a VERY fresh looking Knight KN940A, which looks very well preserved. It all lights up, but all I get is 120 cycle hum through the speakers. So will Probably start on this first.

Justin

 

[BillWojo]

Nothing worse than a project that has been hacked up. I'm not sure what kind of deal that you made but I would be looking to return that Scott and keep looking for a unmolested unit. That mess is going to cost you many, many hours trying to figure out what was done, what may have been chopped out and or modified. Not worth the struggle in my opinion. Not saying it can't be fixed but the level of work needed is much higher than restoring a unmolested unit.

BillWojo

 

[Tinkerbelle]

Fixed the title for you.

I have to agree with BillWojo; once it is hacked up you have added investigative work to understand what was done. There is always the option of reverting any modified sections to Scott's original design. I would start with that multisection cap area. This 299A rebuild thread has some good info and several underneath pics (around pages 3-4) that might help. There are no doubt a few other such threads here if you do a search on this forum.

 

[Dandy]

It doesn't look too bad to me, as long as you read the restoration threads here first and check the changes against as schematic. Just work slowly and carefully, and be grateful that some of the electrolytics and film chaos gave been changed.

There will be threads or owners here who can post pics of an unmolested unit to compare.

Was it sold as working? Any info on the previous owner?

 

[Plimpington2]

Nothing worse than a project that has been hacked up. I'm not sure what kind of deal that you made but I would be looking to return that Scott and keep looking for a unmolested unit. That mess is going to cost you many, many hours trying to figure out what was done, what may have been chopped out and or modified. Not worth the struggle in my opinion. Not saying it can't be fixed but the level of work needed is much higher than restoring a unmolested unit.

BillWojo

I paid $100 for it. I paid $100 for the Knight as well. The Knight is stock, and I think only a few hours, and, maybe, $75 away from working a treat. Here’s a pic of the front - it looks brand spanking new!!

 

[Plimpington2]

Fixed the title for you.

I have to agree with BillWojo; once it is hacked up you have added investigative work to understand what was done. There is always the option of reverting any modified sections to Scott's original design. I would start with that multisection cap area. This 299A rebuild thread has some good info and several underneath pics (around pages 3-4) that might help. There are no doubt a few other such threads here if you do a search on this forum.

Thanks for fixing title. I didn’t seem to ha e a way to do that after it posted. I’ll have a look at that rebuild thread.

 

[Plimpington2]

It doesn't look too bad to me, as long as you read the restoration threads here first and check the changes against as schematic. Just work slowly and carefully, and be grateful that some of the electrolytics and film chaos gave been changed.

There will be threads or owners here who can post pics of an unmolested unit to compare.

Was it sold as working? Any info on the previous owner?

No, no, not sold as working. In fact, the shop has a full bench and you can do any diagnostics you want before buying, including testing tubes. I knew what it looked like before i picked it up. He wanted much more money for it (he didn’t know what it looked like underneath) before I had a look. The face is very clean, and the iron seems to be good. So once I get it up, it will be a very nice unit for about $300 all in + my time.

 

[Dandy]

So the price reflected the 'mods' done. A very nice deal, given the good iron. I paid twice that for a very hacked up SCA-35. But they are rare over here.

Ps caps not chaos! Darn tablet 'autocorrects'.

 

[njcanuck]

That Scott at $100 is a steal! While maybe a bit daunting as a first restore project, these amps are fairly simple once you get a feel for them and they are all fairly similar. Concentrate on the different circuits one at a time; eg: bias circuit, power supply, amplification, etc. Test after each change. There are many Scott schematics in the AK database. My 299a restoration thread is here: https://www.audiokarma.org/forums/index.php?threads/restored-my-hh-scott-299-–-long.490854/

PS: See if you can get it basically working before you start the restore.

Good luck!

 

[gadget73]

Not a big deal, you'll just have to do some detective work to see what has been changed. For that price you've got nothing to lose.

 

[drew_t]

Does it work?

 

[Plimpington2]

Does it work?

I haven’t plugged it in. I want to go through it with a schematic first since it has at least 4 problem spots.

 

[Bradbrews]

I suspect that those problem spots are simply the remains of disconnected can caps and the resistors that were attached to them. In general it looks like the can caps have all been replaced by new(er) parts. The 4 hidden below the electrical tape are the bias supply caps. The cuts at the switch may be just to bypass the scratch filter (or whatever that one is). Although not necessarily the neatest job, it looks like it may be ready to run. The buried caps on the front panel are tone control caps. It won't hurt to leave them alone for now unless they have failed.
By all means, check out what was done compared to the schematic, but you may be pleasantly surprised.

 

[Plimpington2]

I suspect that those problem spots are simply the remains of disconnected can caps and the resistors that were attached to them. In general it looks like the can caps have all been replaced by new(er) parts. The 4 hidden below the electrical tape are the bias supply caps. The cuts at the switch may be just to bypass the scratch filter (or whatever that one is). Although not necessarily the neatest job, it looks like it may be ready to run. The buried caps on the front panel are tone control caps. It won't hurt to leave them alone for now unless they have failed.
By all means, check out what was done compared to the schematic, but you may be pleasantly surprised.

That would be fantastic!! Although I do want to replace those blue caps with nice metal can caps. And also work through the circuit so i understand it better. I don’t need the scratch filter, for sure. Would would like to clean things up.

Btw, does anybody know a reliable place to buy new wood cases for these? The guy who runs McIntosh Cabinets (who makes these) says he is no longer doing it for the time being and is not taking requests. I’d MUCH rather source a new box than a vintage one, as the new ones seem to look much nicer.

 

[Bradbrews]

Those blue caps are most likely 32 MFD x 500V x 2 multi section cans. They are just covered in blue plastic instead of aluminum. I went with Black plastic ones on the LK-72 I did. I was not too keen on the Blue either, but color aside, they are likely correct. IIRC the originals were probably 20 MFD x 450V or so.

 

[Plimpington2]

Those blue caps are most likely 32 MFD x 500V x 2 multi section cans. They are just covered in blue plastic instead of aluminum. I went with Black plastic ones on the LK-72 I did. I was not too keen on the Blue either, but color aside, they are likely correct. IIRC the originals were probably 20 MFD x 450V or so.

You have an LK72? I love the look of that amp - the black and chrome/gold just looks fantastic. That’s next on my list. Would look amazing in a cherry cabinet!

 

[Bradbrews]

Some pictures of the restore here:
https://audiokarma.org/forums/index.php?threads/brown-faced-scott.859471/

 

[primosounds]

I haven’t plugged it in. I want to go through it with a schematic first since it has at least 4 problem spots.

First thing before going at any rebuild on the 299 is to check the transformers. A bunch of cut resistors looks like someone was trying to track down a short by removing circuits or components from the main circuit. It is easy to check the PS and transformers with a variac and a SS replacement that plugs into the 5ar4 socket. Then if you have B+ at the CT of the OPT and the same B+ at the 7189 plate you are 99% sure your OPT are good. And at the same time you can check filament voltages and the bias tap. All voltages would be roughly 10% of full voltage if you set the variac at 12 vac.