klh model 8 restoration

[bjornklh]

just got a klh model 8.

what a beauty, ive been saving for one for a while.

its bigger then i thought it would be, i somehow imagined it to be the size of a model 18 for some reason, didnt really think on that one..

it has amperex power output tubes and raytheon tubes for the rest.

are these decent tubes, or will it sound better with better ones?

i was surprised that it didnt have more clarity, i have a dynakit st-70 running with advent 1s and its about the clearest thing ever,

and this radio was kinda fuzzy. very very warm sound, but not as clear as i expected.

could this be the tubes?

it also has a slight hum at idle, that is seperate from the volume control, ie it hums if you turn the volume all the way down you can hear it.

what would one of these need to be reliable and sound the best?

please keep in mind im on a budget, but want this thing to last.

if the filter capacitor is going like it sounds like, would that affect sound quality and clarity.

also is there any way to reseal the cloth surrounds on these speakers, any way to get grill cloth off?

seems like it may need that?

any info would be very very very helpful, as i want to use this thing soon, but am afraid to plug in because i dont want it to die an early death due to a shorted cap.

thanks all the best

[JKent]

Here are a few thoughts:

Grille: The grille cloth is usually stained and is made of unobtainium. It is very stiff and was cut just about ¼” bigger than the opening so it could be slipped into a groove around the perimeter. Furthermore the cloth is usually stained and if you try to wash them they will shrink and/or unravel. I have finally decided the best bet is to make a board out of 1/8” Masonite and glue Irish Linen to it. You can find some discussion here:

http://www.classicspeakerpages.net/IP.Boar...?showtopic=2574

Electronics: I am NOT a technician so others may be able to give better advice. It is usually not necessary to replace the tubes, and a complete re-tube is a waste of money IMHO. It IS a good idea to replace electrolytic caps (they are nearly half a century old!!).

There is a big “can” type capacitor rated four times 60uF, 150v. You can get a suitable replacement at

http://www.tubesandmore.com/

this one will do: CAPACITOR, ELECTROLYTIC, 50/50/50/50 µF @ 350 VDC C-EC50X4-350

but it cost $35. They also sell vacuum tubes btw.

The cheapo way to do it is to remove the can and hollow it out, then put four 47uF radial caps inside. You can use these:

http://www.partsexpress.com/pe/pshowdetl.c...FTOKEN=16072720

or these:

http://www.partsexpress.com/pe/showdetl.cf...number=020-1692

There is also one 5uF axial electrolytic in the center of the chassis, under another cap. Replace that. I don’t remember if there may be one more electrolytic.

Knobs and pots: If you have to replace a pot—good luck. The simple on/off switch is impossible to find. I used one substitute that was physically much larger and necessitated cutting the chassis. On another of my radios a previous repairman used the on/off section of an on/off/volume switch. Good replacements for the small black knobs are these “Kilo DDS” series in the Matte Black finish, but they cost about $10 apiece.

http://www.nteinc.com/pot_web/pdf/DD_DDS_Series.pdf

Cabinets: Early cabinets were solid walnut. Later ones were veneer. The solid can be sanded aggressively. I would NOT sand veneer. For that I recommend Howard’s Restor-a-Finish, available at hardware stores, online and Home Depot. You cannot put polyurethane or any hard finish over it, but Minwax Antique Oil Finish works well. Tung oil may also work. A lot has been written in these pages about refinishing old speakers, so do a little looking. Just bear in mind that, unlike most classic speakers, the Model Eight’s original finish was apparently lacquered, NOT oil. If you have a solid cabinet and sand it down you could use varnish or lacquer if you choose.

FYI here is a thread on the two kinds of speaker drivers used:

http://www.classicspeakerpages.net/IP.Boar...?showtopic=4348

I DOUBT that the speaker surrounds need to be resealed. My advice: Leave them alone! You can search here for info on using Permatex on cloth surrounds but again my advice is to leave them alone. And if your grille cloth is good, DO NOT remove it or you may ruin it.

The KLH Eight is a FANTASTIC radio. Maybe the best radio ever. Take care of it and it will reward you with magnificent sound!

Good luck! And be sure to read CSP member Andy's article here:

http://www.antiqueradio.com/Jun05_Hayden_KLH.html

Kent

PS: Here are some pictures of the knobs, the switch I replaced, the hollowed-out 4-part cap, and location of the 5uF electrolytic.

[bjornklh]

first off, thanks thanks thanks sooo much. this is like the best response ive ever gotten to anything, so much info, so thank you.

the grill cloth seems to be good, so i am not going to mess with it.

i think i may eventually invest in some telefunken tubes, its running with amperex output tubes, which seem to be rated pretty good, but im sure a pair of nos telefunkens could do no harm to the sound, although i may have to sell a kidney to get a pair.

hmm kidney, or tubes?

Thanks soo much for the info on the caps, and the pics, so helpful.

is there any precautions i should take puting the caps in, or any procedures i should follow? i know how to solder, but its been a while so i shall practice on a 1986 soundesign radio or something first to make sure i get a clean soldier. how long does it take for caps to fully discharge, i mean i know i shouldnt like stick my tounge in the unit right after turning it off or while on , but not sure how long it takes. these dont have a live chassis like the old zeniths do they?

how exactly would i hook up the 4 caps, would i just solder them in series with one end of the four for positive and one for negative making sure to keep the sides straight? like negative of one to a wire to negative of where old cap hooked up, then positive to the negative of the next cap, and the positive of that one to the negative of the next one until it goes back to the positive end on the chassis?

the pots seem pretty clean, one of the knobs is pretty beat up, so i will look for replacement. the tuner sounds kinda dirty, not sure how to clean out, maybe air inside the gangs?(not sure if correct word) on the inside

it hasone of the solid walnut cases, but it is in pretty good shape with one or two small watermarks, not sure how to remove, but i will probably just polish up real well with oil, i love the original finish to this stuff.

i love this radio already, i cannot wait to get it recapped. im scared to turn it on with out new caps. it really did sound amazing when i had it running. henry kloss was a genious, her really was, he has contributed soooo much to home audio, and people dont even know it, no one has contributed like him, his stuff really was on point.

thanks again sooo much, i really appreciate the info, really made my day.

[JKent]

Hi

On the subject of new tubes, remember: New tubes require re-alignment. Do you have a shop where you can have that done?

I have not had any ill effects from handling these caps. Then again, I never put my tongue on one. I think you can discharge them with a screwdriver if they make you nervous.

For the quad cap--the easiest thing is to buy a new one. But if you want to stuff the old one you must remove it by untwisting all the tabs on the bottom. Then there are 4 lugs on the bottom, each marked with its own symbol (half-circle, triangle etc). Make a note and drawing of what is soldered to each lug. You can cut the lugs off. Then you have to get the phenolic plate off the bottom and start digging out all the stuff inside. Probably full of PCBs and other bad stuff. Get it all out. You then use 4 individual radial caps. Make sure they all fit inside the can. Solder some wires to the leads and insulate the leads with heatshrink tubing. All of the neg leads can be connected together (you can probably leave them bare if you want) and they must be grounded to the chassis. The 4 positive leads are connected, one to each component or wire that was on the lugs originally. DO NOT connect the caps together in series. The "can" replaced 4 INDIVIDUAL caps. The only reason to stuff the can is for appearance. In other words, the 4 leads replace the 4 lugs. In the photo of the caps in my previous post, the red leads are pos, the green leads are neg. I did 2 and 2 to fit in the can. Attached is a photo of the 4 caps inside the can, and one that shows the red and green leads emerging from the square hole where the can was. You can also see the red varnish on the joints. Don't be confused by the colors of the caps themselves--I had 2 on hand and bought 2 more locally. They are all 47uF, so it does not matter which red lead replaces which old lug (in other applications it does matter because the quad may have 4 values. In this case the values are all the same).

It would be nice to use a terminal strip if you can fit one in there. I left the wires loose, which is a little sloppy, and painted any bare wire or solder joints with insulating varnish.

Good luck

Kent

[bjornklh]

Hi

On the subject of new tubes, remember: New tubes require re-alignment. Do you have a shop where you can have that done?

I have not had any ill effects from handling these caps. Then again, I never put my tongue on one. I think you can discharge them with a screwdriver if they make you nervous.

For the quad cap--the easiest thing is to buy a new one. But if you want to stuff the old one you must remove it by untwisting all the tabs on the bottom. Then there are 4 lugs on the bottom, each marked with its own symbol (half-circle, triangle etc). Make a note and drawing of what is soldered to each lug. You can cut the lugs off. Then you have to get the phenolic plate off the bottom and start digging out all the stuff inside. Probably full of PCBs and other bad stuff. Get it all out. You then use 4 individual radial caps. Make sure they all fit inside the can. Solder some wires to the leads and insulate the leads with heatshrink tubing. All of the neg leads can be connected together (you can probably leave them bare if you want) and they must be grounded to the chassis. The 4 positive leads are connected, one to each component or wire that was on the lugs originally. DO NOT connect the caps together in series. The "can" replaced 4 INDIVIDUAL caps. The only reason to stuff the can is for appearance. In other words, the 4 leads replace the 4 lugs. In the photo of the caps in my previous post, the red leads are pos, the green leads are neg. I did 2 and 2 to fit in the can. Attached is a photo of the 4 caps inside the can, and one that shows the red and green leads emerging from the square hole where the can was. You can also see the red varnish on the joints. Don't be confused by the colors of the caps themselves--I had 2 on hand and bought 2 more locally. They are all 47uF, so it does not matter which red lead replaces which old lug (in other applications it does matter because the quad may have 4 values. In this case the values are all the same).

It would be nice to use a terminal strip if you can fit one in there. I left the wires loose, which is a little sloppy, and painted any bare wire or solder joints with insulating varnish.

Good luck

Kent

thanks soooo much. i will email if i come up with anymore questions, which i probably will. i was going to take to guy in my area to do this, but i sounded excited about it, so i think he may try to overcharge me, and since im in collage and i had to just about sell body parts to get it, any money saving would be good. it will be a few before i can start, but cannot wait to get her going. thanks soooo much.

out of curiousity, how do these sound compared to the model 21s? as far as sound quality.

i also have a model 20 turntable, im sure it needs caps too, works fine but sound not the best, i fear the amount of stuff involved in that however...

well thanks again for all the info

[bjornklh]

yeah i dont think i would have braved any of this without your help. i will probably still get her looked at, but this way when he trys to say he will need 5 hours bench time to work on it i can say i know what im doing, and do the stuff after he checks it. i took a tube amp to a regular shop once and they looked at me like i was from mars. it really is amazing stuff though. i dont know why they changed the technology to solid state. actually i know one reason why, running tube stuff once in a blue during summer with no ac. heh could heat a small apartment with my dynaco. took me friggin 5 years to finally find a tube amp. anyways rambling, thanks so much again and stay in touch.bjorn

[JKent]

I have restored many 21s and 8s and the 8 is my all-time favorite. YMMV

Don't know where you are, but here in northern NJ Bristol Electronics has done a fine job on a few of my Eights, as well as my Thirteens, Scott tube tuner and an assortment of other vintage stuff. I recommend him highly!

Kent

[bjornklh]

say jkent, how do i order those knobs, and which one in specific do i get. couldi order them through you somehow? just get back to me when you have the time, thanks so much. bjorn

[JKent]

say jkent, how do i order those knobs, and which one in specific do i get. couldi order them through you somehow? just get back to me when you have the time, thanks so much. bjorn

Hi Bjorn

I don't have a business--just a hobby.

The knobs are manufactured by Kilo.

http://www.kilointernational.com/knobs/dds...dds_series.html

I buy them at my local electronics store for about $10 apiece. They are packaged by NTE and are marked:

504-0027

DDS-90-4-5

.925 x .625

.250 dia shaft

Black Matte

so..they are the DDS series, 1/4" shaft, matte black (also available in gloss but matte is closer to the original).

You can probably find them online at digikey, allied and others.

http://parts.digikey.co.uk/1/1/120290-knob...dds-90-4-5.html

http://www.alliedelec.com/Search/ProductDe...DS%2D90%2D4%2D5

Good luck

Kent

[Johnson]

Thank you so much for the links to those knobs. They look like a suitable replacement.

[JKent]

Thank you so much for the links to those knobs. They look like a suitable replacement.

Glad to hear that was helpful. If you have not done so, you may want to check out my KLH Eight restoration booklet:

http://www.classicspeakerpages.net/library...lh_model_eight/

The booklet shows the Kilo knobs and compares them to the originals.

I've refined the "cap stuffing" and other things mentioned above. Disregard my description of how to stuff the 4-part can and refer instead to the booklet. It's easier than what I described and the result is more authentic-looking.

The Eight is a GREAT radio. After replacing all the paper and electrolytic caps, checking the tubes (replacing only bad ones) and having it professionally aligned, the Eight is second to none. I just finished a recap job today, and tomorrow I'll be heading over to Bristol Electronics to drop this radio off for alignment and pick up a couple of Eights and a couple of Thirteens Tim just aligned for me. One of the Eights is yours, Bjorn.

I'll be putting the Eights on that auction site. Any CSP member interested in one before it gets listed can PM me.

Kent

[JKent]

A year has passed and I've learned a couple o' things. SO... "Rev 2" of the KLH Model Eight Restoration Guide is now in the Library (so is the original, but Rev 2 is better )

http://www.classicspeakerpages.net/library...lh_model_eight/

It's a big download--11.66 MB--so it will take a couple of minutes.

Feedback and/or suggestions welcome.

Kent