Harman Kardon HK 330B recap, restore and upgrade BOM part list (kinda)

Selecting caps isn't hard to do a regular recap. Stick with the caps that the techs recommend. Panasonic FC and FM, Nichicon HE and PW. MTF also says to use film (extremely low leakage) or Nichicon UKL for low leakage as called out in the Pioneer service manuals with those letters they use to describe the caps. Any of the Nichocon Auidio Caps or Boutique Audio Caps is up to the others to figure out. What dlucy is doing, upgrading the circuit takes a bit of experience and knowledge gained through experience or studies.
 
The completely-replaced PHONO EQ RIAA board in the HK330B looks boring,

Yup, using those high performance Vishay/Dale RN60 light brown resistors sure does take the color pop out of the board. Not going with some fancy audio caps with gold/black coloring also keeps the looks from being the reason to do the recap. Fortunately this board sits inside a the 330B and you won't need to be looking at it while enjoying its improved performance. I mentioned in one post that I select capacitors by color and posted the list of main color and printed color for the Nichicon line. I wonder how many believed that is the way I select caps? Since new is probably better than old, it probably doesn't matter if the new cap will meet the specs needed for that application.
 
Selecting caps isn't hard to do a regular recap. Stick with the caps that the techs recommend. Panasonic FC and FM, Nichicon HE and PW. MTF also says to use film (extremely low leakage) or Nichicon UKL for low leakage as called out in the Pioneer service manuals with those letters they use to describe the caps. Any of the Nichocon Auidio Caps or Boutique Audio Caps is up to the others to figure out. What dlucy is doing, upgrading the circuit takes a bit of experience and knowledge gained through experience or studies.

Yep. I kept running into situations where something wasn't available in Nichicon KL or PW, so I had to understand why KL was recommended here and why PW was recommended there. Then why film was recommended. Then why poly film was recommended over... My cheat sheet keeps getting more and more complex as I learn from you guys here on AK.
 
Yep. I kept running into situations where something wasn't available in Nichicon KL or PW, so I had to understand why KL was recommended here and why PW was recommended there. Then why film was recommended. Then why poly film was recommended over... My cheat sheet keeps getting more and more complex as I learn from you guys here on AK.

This right here is what's holding me back from just diving in and making a BOM. Don't want to derail this (excellent) thread but is there somewhere I could start reading up on this?
 
Fortunately this board sits inside a the 330B and you won't need to be looking at it while enjoying its improved performance.

exactly ;)

And I'll probably give this one to the local used record shop to sell so some new or reborn vinyl head (like me) will have something real to hear their records through, and that means the only thing they'll ever know about the refurb is the wacky sticker I attach to the bottom:

"listen! this unit has be unprofessionally serviced, restored and upgraded. it may catch fire and explode. or not. until then, it should sound really great. i'd drone on and on about all the cool stuff inside here, but i seem to have run out of space for this sticker...."
 
I had to understand why KL was recommended here and why PW was recommended there. Then why film was recommended. Then why poly film was recommended over... My cheat sheet keeps getting more and more complex as I learn from you guys here on AK.
First, don't be putting me in that group of those teaching. I just started the Capacitor Abyss thread to do some learning not teaching.

You have it right, understanding and learning are necessary here on AK and I'm sure just after you complete a recap, you are adding a new item to your cheat sheet that would have made a difference in the unit you just finished. And so it goes. live and Learn. Fortunately, just doing the work will make the unit kinda like new and in most cases that is fine. So no reason to go back and redo it.
 
This right here is what's holding me back from just diving in and making a BOM. Don't want to derail this (excellent) thread but is there somewhere I could start reading up on this?

I can post what I've scribbled down so far in a new thread. It'll get lots of "you're wrong" for all kinds of different reasons, but that, too, should be educational. If it gets too intense, I'll just PM you the Word doc in its current state. My only request is you offer whatever of it works for you and what you learn beyond that back to the AK. If you don't mind.
 
I can post what I've scribbled down so far in a new thread.

You can do it here cause this thread is only 3 pages and growing and we need some more good content to get this discussion moving even more.
You could post it in the Capacitor Abyss since that is a place where there is a lot of discussion about caps. seems appropriate, too.
A new thread...well I guess we'll find it if you do that.
 
You can do it here cause this thread is only 3 pages and growing and we need some more good content to get this discussion moving even more.

I like your idea better than mine.

You could post it in the Capacitor Abyss since that is a place where there is a lot of discussion about caps. seems appropriate, too.

Maybe you can curate whatever we say here that would fit best in Capacitor Abyss. That way, no matter how someone is searching, they'll find something interesting.
 
Ok, on to the one reservoir capacitor in the power supply circuit. This is C6 and its job is to provide a reserve of power in between peaks coming from the AC-to-DC conversion of the bridge rectifier 4 diodes.

Choosing a replacement cap for this power supply reservoir cap:

What voltage rating should I choose - In the original circuit, this is a 2200 uF cap rated for 63V. Looking at the schematic, the bridge is supposed to normally provide 53.5V. That's too high since ConradH advises us to keep the normal operating voltage of a cap at 60-70% of the cap's voltage rating. So, I don't want a 63V cap there; I want more like a 80V or 90V cap. Ok, so I'll be looking for a 80V or 100V voltage rating cap.

POWER SUPPLY CAP 00.png
POWER-SUPPLY-CAP-01-IMG_4034.png POWER-SUPPLY-CAP-02-IMG_6810.png

What kind (family or series) of cap is best here - This is a power supply cap, so the most-important characteristics are high ripple and low ESR. A higher ripple rating means the DC output by the cap will be smoother (and that means less noise) and the low ESR (effective resistance) means this cap will get less hot than a higher ESR cap (because higher resistance translates into higher temperature as the power bleeds off due to the resistance). So, I'll be looking for a capacitor family or series whose characteristics (from that family's datasheet) are high ripple and low ESR (as opposed to low leakage). The opinion I've heard most here on AK (thank you MarkTheFixer and others) is to choose the Nichicon PW series of caps for power supplies (or anything, really, that isn't carrying the actual audio signal). So, I looked for a cap in the PW series that was at least 2,200 uF "big" and could handle at least 80V, preferably 100V. There are none, at least none in that series that Mouser carries. So, the "how big a cap" will have to wait a little.

How big a cap should I choose for this - the 2200 uF is sufficient for the original design, its operating characteristics, and the components leading up to this cap. However, I'm OK with spending a little more money (usually less than a buck or two) to beef this component up. My ears aren't great, so my belief is that a slightly or somewhat larger cap here will provide additional power reserves for those unusual times when the music you're playing has great, sudden demands (dynamics) and you're playing it kinda loud (like more than 50% volume). Having another 20% or 50% reserve power should let this cap continue to feed the hungry power transistors, at least for a moment. There is lots of debate about this. I predict some of that debate will continue in this thread right after I hit "post". No matter. This is my opinion and I'm just sharing what logic and desire I used to choose this particular cap. So, if 2200 uF is what the circuit called for initially, I'll be looking for the next couple of sizes larger than that: 3300 uF and maybe even 4700 uF (typical increments in many cap families).

Searching on Mouser for Nichicon, through hole mount, over 2200 uF, 80V and 100V doesn't return many hits. That's because most of the caps in this capacitance range are so large they aren't commonly soldered to the PCB (i.e. through hole), so I remove the "through hole" parameter and let "snap in" and "screw terminal" mounting styles be included in the listing. NOW I'm getting plenty of hits. So, I sort the results by ripple, then diameter, then cost to get a feel for "what is available that will work", "what is available that is same-diameter or smaller (so it'll fit in the mounting collar)", and what are the lowest-cost few choices within those results.

What comes out of all this sorting and resorting is a 4700 uF 80V cap that is the same diameter as the original ELNA 2200/63 and isn't very expensive. It happens to be a snap-in and I can work with that.

The new, snap-in mounting style cap just needs some extra leg added to each terminal to give the original wires enough room to be attached.

POWER-SUPPLY-CAP-03-IMG_6814.png

The replacement fits in well and it looks good (even though no one will ever see this).

POWER-SUPPLY-CAP-03-IMG_6818.png POWER-SUPPLY-CAP-04-IMG_6968.png

There is a big deal about bigger caps, though, and that is inrush current. As soon as you turn power on, the reservoir cap will want to fill up, the AC transformer will let in as much AC from the wall outlet as it can, and the components between the wall outlet and the reservoir cap will need to be strong enough to handle this short-lived peak flow of current. In this upgrade, I have upgraded the diodes to UF5404's and they can handle 3A continuous and something ridiculous peak. So, they will be OK. I knew I was jumping up (100% increase in capacitance), so I was careful when first turning on the unit and I've watched it carefully through dozens of hours of testing. So, in this particular case, a 100% increase in this cap's capacitance worked fine.

So, when I'm looking for a replacement cap for the reservoir cap (the first cap after the bridge rectifier), I'm looking for a big capacitance, higher voltage, similar diameter, high ripple, low ESR cap. And I don't care much about leakage. So, I'd be looking for something in the Nichicon PW series and, if I can't find what I need there, use the above parameters to search more broadly for something that has all the qualities I want from this specific-purpose position in the circuit.

There are often more than one secondary on the transformer. For instance there might be another lower-voltage secondary to power the tuner circuits and there is very often a much lower voltage secondary used to run the lamps. Those additional power supply circuits, if they rectify the AC, will likely have a reservoir cap, too. The same guidelines can above can be applied to those circuits. It might not be as useful since these circuits aren't supplying transistors that often deal with highly-varying demands (i.e. dynamic music), but the prices for these caps is gonna be really low due to their size and voltage, so what the heck. Go crazy.
 
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Choosing the replacement diodes for the bridge rectifier:

The schematic tells us the diode models used and it tells us the output voltage of the bridge, 53.5V, so we know most everything we need to find a modern replacement. The only thing missing is the continuous current.

Bridge diodes.png

The VO3(E) diodes are all sticking up from the board and sleeved:

POWER SUPPLY RECTIFIER 1-1 IMG_6795-closeup.jpg

So, I can search AK for the diode part number VO3(E) or I can look around the net for the same. It's hard sometimes to find these. I've found AK is the best first place to start, then look for datasheets, then look for cross-reference sheets, then look for semiconductor or diode cross-reference books from the 60's and 70's.

VO diode stats.png

The VO3(E) is 400V RPRV (max voltage that can be safely passed through continuously) and 1.3A average forward current (max continuous current).

So, in general, if the original rectifier diodes call for less than 1A average forward voltage, then the 1N400n diode series could be used. I prefer to use the UF400n diode series since they are ultra-fast and soft-recovery, but either of these two series-es can handle 1 amp of current. Then you select which of the series, UF4004 for example, to get the right voltage.

In the case of the HK330B, however, this power supply's bridge wants diodes that can handle 1.3 amps continuously. So, for these situations, where you need more than 1A and up to 3A continuous, I look for the UF540n series since they handle up to 3A. I looked at the UF540n series datasheet, picked the specific model that handles at least 400V PRV, and I used the UF5404.

POWER-SUPPLY-RECTIFIER-1-2-03-IMG_6807.png
 
Great Thread! I'm listening to my 330B as I post. It will need attention soon.

Also have two HK730s needing work. Total newbie working (very slowly) to muster the courage.
 
Great Thread! I'm listening to my 330B as I post. It will need attention soon.

Also have two HK730s needing work. Total newbie working (very slowly) to muster the courage.

If you can, do a simpler, cheaper, don't-care-if-you-ruin-it unit first... learn from that... then move on to ones you care about.

I started with a Pioneer SX-450, there were lots of help threads already here on AK, and I learned a lot... and I ended up with an awesome-sounding "little" silver-face Pioneer.
 
If you can, do a simpler, cheaper, don't-care-if-you-ruin-it unit first... learn from that... then move on to ones you care about.

I started with a Pioneer SX-450, there were lots of help threads already here on AK, and I learned a lot... and I ended up with an awesome-sounding "little" silver-face Pioneer.

I've got an obscure one I could start a thread about. (I'm working up to my Scott 399 tube rig)
 
If you had a choice, you might want a more-common lesser-value-to-you unit to start with so more people here on AK could chime in with their experience. Some crazy people (i.e. me) might even buy a super-cheap $10 SX-450 or similar at a garage sale just so have a risk-free starting point. Actually, I bought a Kenwood KR-6160 as my test-and-learn platform, opened it up to find a moderately-dense clutter of wires and boards, closed it back up, and looked for a simpler, more-common low end unit. But everyone has their own ideas; I don't think any are bad.
 
The MAIN AMP board will need a lot of work. There are numerous small signal transistors and four output transistors that all need attention, there are several high wattage low resistance resistors that are likely to have been stressed over time, a bunch of electrolytic caps, maybe a tantalum cap or two, and two trimpots in either channel. Oh, AND this design uses output capacitors (just before the amplified signal goes to the speakers) and it uses varistors (two or three diodes in series inside a molded plastic part used to vary the output transistor bias based on temperature, often directly mounted to or near the heatsink [so as to get some good temperature variation]).

The before images:

MAIN-AMP-IMG_4028.png MAIN-AMP-IMG_4029.png MAIN-AMP-IMG_4036.png MAIN-AMP-IMG_4037.png MAIN-AMP-IMG_4038.png MAIN-AMP-01-IMG_4023.png

Yep, that's one massive, crazy, multi-piece heatsink for a low-wattage receiver. more on that next....
 
've got another 330B unit to restore, but I'm moving so it has to wait. I'll be using different families of resistors in that one.

Good stuff dlucy, making for an enjoyable read. I think I'll end up spending some time refurbing my 330b.

Apologies if I missed it but what's the impetus for trying different resistors?
 
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Ok, and the during images of the MAIN AMP board

MAIN-AMP-01-IMG_6732.png MAIN-AMP-02-IMG_4041.png MAIN-AMP-02-IMG_6730.png MAIN-AMP-03-IMG_6733.png MAIN-AMP-04-IMG_6734.png MAIN-AMP-05-IMG_6735.png MAIN-AMP-06-IMG_6736.png MAIN-AMP-07-IMG_6742.png

The heatsink is a huge, two-part affair and it physically attaches to the rear panel of the chassis. So, you'll be using a good deal of thwermal insulator.

Speaking of thermal stuff, don't forget that you'll need more than just what is in the recap BOM if you replace, repair or just pull and then return the output transistors. You'll need:

 
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