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

dlucy: Thanks so much for putting this together! I just finished a Sansui AU-555a and a HK 330b and I am in the middle of my 2nd HK 330b. I have learned a lot and am still learning more every day thanks to people like yourself who take the time and effort to post these kinds of threads. Thank you, thank you, thank you! :rockon:
 
A few more before-and-during and then the after-images of the MAIN AMP board

MAIN-AMP-08-IMG_6743.png MAIN-AMP-09-IMG_6762.png MAIN-amp-10-IMG_6765.png MAIN-AMP-11-IMG_6963.png MAIN-AMP-12-IMG_6965.png MAIN-AMP-13-IMG_6969.png

Those two little components high on yellow sleeves are the varistors. I chose not to replace them this time. There is an awesome thread on how to make functional replacements for these STVH3 or whatever, but I've no reason to replace them. For once, I'm acting in a sane fashion. ;)

The new trimpots are pretty, but I don't like them much. They lay down on the PCB so you can apply pressure to them during adjustment, but otherwise I'll think I'll look for something different for the second HK 330B I've got to refurb.
 
For those of you who are working on your own original BOM for a recap of some piece of gear that hasn't been covered well yet, one of the big issues for me was "when to use signal-handling capacitors versus when to use power-handling capacitors?" For signal-handling ones, you'll want low leakage. For power-handling ones, you'll want something else (low ESR, high temperature, specific diameter, etc.).

I looked thorugh a bunch of "how to read electronic circuits" books and threads here on AK. The point is, basically, identify the caps through which the signal is going to pass and find low leakage electrolyitcs or film replacements for them. Then, for everything else, choose something in the power-handling camp.

If you don't know or can't tell, ask AK. This is one of the threads where I made a good guess, then asked AK and plenty of people chimed in with help. THAT made the BOM creation a little easier.

http://www.audiokarma.org/forums/in...th-through-a-transistor-based-circuit.734534/
 
Apologies if I missed it but what's the impetus for trying different resistors?

My apologies for taking so long to reply. I've been looking through a bunch of posts and I can't seem to find the one that drove me to say "I gotta try these other resistors next time."

There was some exchange of posts, between one of the long-time experts here on AK and I, where they said "why aren't you using X" or "I've always had better luck with X" and that caused me to question my fixation on Vishay. But I can't seem to find that exchange now. Rats!

If I do find it, I'll come back and share it again here. And share what I end up using instead of the Vishays.
 
I wonder how it sounds? Mine is a little boomy with the KefR300 that I use with the vintage units.

EDIT: Increasing the capacitance of the output-coupling caps definitely increased the bass response, in this case in an unwelcome amount. So, I've switched back to using output-coupling caps of the same capacitance as original and I'm much happier for doing so.

The test speakers I had on my workbench up til now were a pair of refoamed and recapped Infinity RS-10 2-way speakers from the 1980s. Never thought anything was wrong with them. Connecting the newly restored/modified HK330B to them brought in a lot more bass than I'm used to. I had to turn down the bass control on the HK330B for most source, just 1/16th of a turn maybe. And the Infinity RS-10s sounded better at higher volume settings, of course.

Reference Standard 10
Introduced: 1982
Dimensions: 34 x 21 x 20 cm
Bass: 1 x 16 cm
Highs: 1 x Polycell
Suggested for amplifiers with: 15-65 Watts per channel
Frequency range: 59 Hz - 22 kHz
Crossover frequencies: 3000 Hz
Suggested price (pair): RS 9: 196 $
RS-10 are bookshelf speakers 17.7" tall​

So, I swapped in a dinky pair of Infinity SS-2001 speakers I had lying around and which I'd recently refoamed and recapped and, of course, one of the woofers was bad and I hadn't noticed until listening critically to hear if the HK330B was working properly. Sigh.

So, eBay to the rescue for a replacement set of drivers, SimplySpeakers to the rescue for another refoam kit, and now I have a more-neutral-sounding set of workbench speakers.

SS-2001 Sterling Series 2-Way Speaker
Nominal Impedance: 8 ohms
Power Rating: 10-60 watts
Sensitivity: 90dB
Crossover Frequencies: 4500Hz
Frequency Response: 74Hz-20kHz +/-3dB
1x - 1/2" (1.27cm) Polycarbonate Tweeter
1x - 5-1/4" (16.3cm) Woofer
Dimensions: 9"H x 11-5/8"W" x 6-5/8"D
Introduced in 1993
Discontinued 1996
Original Retail Price: $159.00/pair​

And these don't sound too boomy. So, I'm guessing the mods to the HK 330B have unlocked more bass response, especially at the higher volumes the RS-10's demanded.

The change I made to the output coupling caps actually predicted this new behavior. I'd read somewhere here on AK that "the use of 2200 uF of capacitance or less in the output coupling position will cause a roll off (of some amount) of the lower audio frequencies." So, I chose higher capacitance electrolytic caps and I believe that is why, or they are at least contributing to, more bass.

IMG_7252.JPG IMG_7254.JPG
 
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I wonder how it sounds? Mine is a little boomy with the KefR300 that I use with the vintage units.

If I have my wits about me when I go to refurb the second unit, I'll try to do a frequency response analysis before and after. THAT would be interesting and give some quantitative data to the "how does it sound after" discussion.

Any have a link to a good thread here on AK that recommends PC-based frequency response measuring software and techniques?
 
My apologies for taking so long to reply. I've been looking through a bunch of posts and I can't seem to find the one that drove me to say "I gotta try these other resistors next time."

There was some exchange of posts, between one of the long-time experts here on AK and I, where they said "why aren't you using X" or "I've always had better luck with X" and that caused me to question my fixation on Vishay. But I can't seem to find that exchange now. Rats!

If I do find it, I'll come back and share it again here. And share what I end up using instead of the Vishays.
Cool, I'd be interested to read your conversation.

Looks like you left the main amp board stock.
 
Looks like you left the main amp board stock.

That's correct. I did not see any visual evidence of bad resistors and I didn't have any defensible reason to replace them. That being said, many AK'ers think I'm nuts in the first place, so maybe next time.... ;)
 
For electrolytic and tantalum capacitors on the MAIN AMP board (as well as everywhere except the PHONO EQ board) I used the following rough rationale for choosing replacement caps:

Follow the schematic and lump each cap into one of two categories: signal-handling or power-handling.

For power-handling caps

If the cap is 4.7 uF (or close to it), then look for a replacement electrolytic cap
of the same capacitance
and of enough voltage rating so
the stated voltage in the schematic passing through it is only 60-70% of the voltage rating (which often means buying a higher voltage rating cap than the schematic calls for)
and never lower than 35 V​
This is often be a Nichicon PW or HW or HE series.​

If the cap is less than 4.7 uF, then look for a replacement film cap
of the same capacitance
and of enough voltage rating so
the stated voltage in the schematic passing through it is only 60-70% of the voltage rating (which often means buying a higher voltage rating cap than the schematic calls for)
and never lower than 35 V​
and similar (identical, if available) lead spacing
and, if a reasonable cost, choose polyester as the type of film​

For signal-handling caps

If the cap is 4.7 uF (or close to it), then look for a replacement electrolytic cap
with very low leakage (i.e. the Nichicon KL series)
of the same capacitance
and of enough voltage rating so
the stated voltage in the schematic passing through it is only 60-70% of the voltage rating (which often means buying a higher voltage rating cap than the schematic calls for)
and never lower than 35 V​

If the cap is less than 4.7 uF, then look for a replacement film (films caps are much lower leakage [or none] than even KL series) cap
of the same capacitance
and of enough voltage rating so
the stated voltage in the schematic passing through it is only 60-70% of the voltage rating (which often means buying a higher voltage rating cap than the schematic calls for)
and never lower than 35 V​
and similar (identical, if available) lead spacing
and, if a reasonable cost, choose one of these types
metalized polypropylene (best)
polypropylene
metalized polyester
polyester​

I'm sure debate will ensue, but that is my current cheat sheet for electrolytic and tantalum cap replacement choices. If you have better advice, please share it!
 
For electrolytic and tantalum capacitors on the MAIN AMP board (as well as everywhere except the PHONO EQ board) I used the following rough rationale for choosing replacement caps:...

Actually, the cheat sheet I made for myself reads more like this:

There is a thread that went into great detail on the "what to use when replacing a signal-handling cap" here. I wrote myself a summary (after some more research into what was available at Mouser and the datasheets con the cap series I could find). Here's the relevant part of my summary (and remember I'm just a hobbyist copying other, smarter peoples' stuff, so please correct me when I'm wrong):

For capacitors in the signal path, use low leakage electrolytics (like the Nichicon KL series) for capacitances higher than 1 uF and use 50V or 100V stacked film caps for capacitances of 1 uF and lower (when they are available). For the stacked film caps, prefer polypropylene over polyester (Mylar) when size is not an issue. The stacked film caps may end up being too big for the location since electrolytics are typically much smaller.

About 1 uF uF or higher

Nichicon KL series
About 1 uF or lower, use 50V or 100V stacked film (when available)

Wima MKP (metalized polypropylene) (most-preferred)

Wima FKP (polypropylene) (second-best)

Wima MKS (metalized polyester)

Wima FKS (polyester)

Panasonic ECQ-V (polyester variant)​
If the cap that works best won’t fit though the pre-existing holes in the PCB, you can always solder them to the underside of the board and forget about the holes.
 
Another thing I've found myself doing during this BOM development is marking the PCBs for:

  • Actual polarized cap orientation
  • Actual transistor pinout
  • Actual diode orientation
  • Component numbering

The PCBs aren't always labeled with nice silkscreening, they aren't always accurate, and it is easy to determine all this at the time you remove the component.

I take many photos now before and during work so I have a visual reference back to "how it was when I first opened it".

When I pull electrolytic caps I look at the silkscreen printed polarity marking on the PCB to verify it is the same as reality and scribble in a + plus sign if it isn't there and correct already.

For transistors I note the pinout orientation before pulling each one out and then immediately put it on a tester to get the real BCE or ECB order and then verify that on the PCB's silkscreen print. If it is wrong or if there is no pin out indication, I scribble it on the PCB with a Sharpie super fine tip marker.

When I pull a diode, I verify the marking on the PCB (if any) and scribble the correct, actual orientation down if it isn't there or isn't right.

If there isn't a back-of-the-PCB foil diagram in the service manual, I snap a photo of both front and them back in a similar orientation so I have a visual version of the foil diagram for later.

Mark-the-PCB-01-IMG_3274.png Mark-the-PCB-02-IMG_3275.png Mark-the-PCB-03-IMG_6943.png POWER SUPPLY RECTIFIER 1-1 IMG_6802.JPG POWER SUPPLY RECTIFIER 1-1 IMG_6803.JPG
 
Thank you dlucy! AK at its finest. :thumbsup:

I almost understand all of this. Saving the entire thread for future study, and reference when I start my 330b redo (sometime after Christmas).
 
Best. Noob. Thread. Ever!
Many of the questions that I have are addressed here, I've read it over and over, chased the links and feel a *little* less intimidated by it all.
 
PHONO EQ and CONTROL boards done, moving on the the MPX I've got questions:
Your ( @dlucy ) MPX cap list is:
FM MPX board
C301 Capacitor Electrolytic 0.47 uF 50 VDC replaced with Electrolytic 0.47 uF 50 VDC 647-UKL1HR47KDDANA
C302 Capacitor Electrolytic 0.47 uF 50 VDC replaced with Electrolytic 0.47 uF 50 VDC 647-UKL1H010KDDANA
C313 Capacitor Electrolytic 1 uF 50 VDC replaced with Electrolytic 1 uF 50 VDC 647-UKL1H010KDDANA
C314 Capacitor Electrolytic 1 uF 50 VDC replaced with Electrolytic 1 uF 50 VDC 647-UKL1H010KDDANA
C315 Capacitor Electrolytic 1 uF 50 VDC replaced with Electrolytic 1 uF 50 VDC 647-UKL1H010KDDANA
C316 Capacitor Electrolytic 1 uF 50 VDC replaced with Electrolytic 1 uF 50 VDC 647-UKL1H010KDDANA
C325 Capacitor Electrolytic 220 uF 16 VDC replaced with Electrolytic 220 uF 35 VDC 647-UPW1V221MPD6
- Capacitor Electrolytic 1 uF 50 VDC replaced with Electrolytic 1 uF 100 VDC 647-UPW2A010MDD

As I mentioned before I've got no silkscreen on my boards and I can't find a proper picture of the MPX so I'm flying blind.

There are six 1µf 50V electrolytics on the board.

I used six 647-UKL1H010KDDANA caps, is good?

Four 1335 transistors should be replaced as well I imagine?

Thanks
Matt
 
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Absolutely no hurry, all done except for the main board and the power cap.

Appreciate your efforts, this is a much easier unit to work on than the SX-737.
 
Doug, how have the LED fuse bulbs held up? I've got two pioneers that use them in the queue and I'd love to replace the fuse style lamps with something that'll put off less heat and last basically indefinitely. Got a specific seller you like to get them from?

I've raided one of the two for a lamp already for an SX-434 I did for a friend, and if I'm getting in there to replace the one I stole I might as well replace the rest prophylactically.

Cheers,
Nathan
 
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