GP Article: Point to Point Wiring

Discussion in 'Amps and Cabs' started by revgsmall, Feb 2, 2008.


  1. revgsmall

    revgsmall Member

    Messages:
    2,088
    Joined:
    Jan 17, 2002
    Location:
    Sheridan, WY.
    Just got my new copy of GP and read the "All About...Point-to-Point Wiring". Although it was written in diplomatic lingo, I'll bet some of the amp builders are not going to be too happy.

    I own a Mesa Mark IIC+, (two) 1970's era Fender Pro Reverbs, and a Vox AC-15 CC. Amps with the various types of construction that they talked about in the article. So far, no breakdown issues with any of them as long as I have owned them. Sound wise, I just don't know if it makes a difference.

    I just don't have an opinion either way at this point on what makes a better amp. Can anyone point out some things that GP may not have covered?
     
  2. Teahead

    Teahead Member

    Messages:
    1,378
    Joined:
    Dec 12, 2005
    Location:
    Northern Ireland
    I agree that I can hear no great difference when PTP and PCB amps of a similar pedigree are played side by side. I've been told the advantage lies in the ease of repair offered by PTP design, but not being a tech I couldn't really care less about that.
     
  3. teleamp

    teleamp Senior Member

    Messages:
    3,508
    Joined:
    Aug 22, 2006
    Location:
    Central Texas
    Haven't read the article, but here's my .02.

    For the most part, circuit design is the biggest factor on how good an amp sounds as long as it is built properly reguardless of construction type. IMHO, there is only a slight difference in sound between contruction types when the circuit is a very simple circuit with very few parts. PTP amps (I mean where there is a solid mechanical connection that has been soldered, not just lay a wire on or through an eyelet and then soldered) are easier to service by techs that have lots of experience with repairing those types of amps. As a hobbyist builder I prefer to build amps using terminal strip/ptp construction (like a Matchless), to me it is easier than loading a board then having to solder added wire leads.

    The MAIN advantage of good PTP (not eyelet board) construction is ruggedness, but only as long as good mechanical connections were made before properly soldering them.

    MikeY
     
  4. HeeHaw

    HeeHaw Member

    Messages:
    4,961
    Joined:
    Sep 11, 2004
    Location:
    VA
    I don't know if point to point wiring is better, but I guarantee the assembly line at mesa or marshall doesn't measure accross every electrical component to see if it is within spec and performing properly. I am also willing to bet that many of the big manufacturers have their transformer sets made in china for $5 each and probably don't bother checking them for consistency. VHT is probably one of the only exceptions here.
     
  5. bosstone

    bosstone Member

    Messages:
    3,401
    Joined:
    Feb 5, 2006
    Location:
    Oakland CA
    I doubt that there are many point to point builders who measure every component either. In defense of Mesa, I recently bought a 34 year old MK IIC+ that was heavily used with a lot of cuts in the tolex and the inside of the amp was dirty from years of bar smoke etc. Tubes had been replaced and so was the speaker but other than that, after opening it up the amp appeared not to have ever been worked on. At Mesa I watched Mike Bendinelli work on it and other than cleaning up the interior the only thing he could find that looked wrong was a resistor that showed signs of being burnt. Mike replaced it and as a preventative measure suggested replacing 2 of the silver capacitors and one other resistor. The amp sounds great and is well worth the service charge and the retolex job I am about to give it. Then he put it on a scope and actually rapped sharply on the chassis with a small ball peen hammer to find any sighs of bad connections. Some are paying $3,500.00+ for tolex ones. Hard wood versions go for at least $500.00 more than that.
     
  6. SgtThump

    SgtThump Member

    Messages:
    6,887
    Joined:
    Jun 23, 2004
    Location:
    St Louis, Missouri
    Are there actually mass producing factories out there that measure/check every single item before they assemble it (for any product, not just guitar amps)? I honestly don't know, but I highly doubt it. Spot checking for QC is understandable, but I can't imagine a factory checking every item.
     
  7. reaiken

    reaiken Member

    Messages:
    1,775
    Joined:
    Jan 4, 2002
    Location:
    Greenwood, SC
    I don't know about others in the guitar amp industry, but in the other electrical engineering worlds I live in on occasion, it is very common to do a full electrical test on the bare boards and occasionally a full "bed of nails" or "flying probe" test on all loaded components for large production runs - it is called ICT, for in-circuit testing, or ATE, for automatic test equipment. There are machines that can "learn" the board and test all connections to identify misloaded or out-of-spec components. The initial setup charge can be expensive, but if you amortize it over a large run of boards, it is actually rather cheap.

    http://en.wikipedia.org/wiki/Bed_of_nails_tester

    http://archive.evaluationengineering.com/archive/articles/0800low.htm


    There is no doubt that you can get far better consistency with PCB than you can with PTP. The main advantage of PTP is ease of repair, unless it is true "bird's nest" PTP, which can sometimes be a bear to trace a circuit down and troubleshoot.

    Randall Aiken
     
  8. usc96

    usc96 Member

    Messages:
    1,516
    Joined:
    May 14, 2006
    Location:
    Where the weather is nice.
    If they sound the same, I don't see the benefit in paying that much more. Hell, if your PCB version breaks, just buy another one. If would probably be cheaper to buy 2 PCB amps than to buy just one of the comparable PTP versions put out by some of the brand name companies.
     
  9. SgtThump

    SgtThump Member

    Messages:
    6,887
    Joined:
    Jun 23, 2004
    Location:
    St Louis, Missouri
    Oh, what do you know about building amps anyway!!!!!! :D;)
     
  10. reaiken

    reaiken Member

    Messages:
    1,775
    Joined:
    Jan 4, 2002
    Location:
    Greenwood, SC
    Not nearly enough, believe me! :)

    RA
     
  11. 2x6L6

    2x6L6 Supporting Member

    Messages:
    466
    Joined:
    Mar 3, 2004
    Location:
    Talkeetna Mtns.
    Isn't there a semantic issue here (haven't read the GP article, just speaking generally) - or perhaps a misunderstanding by many of us (possibly including me!)? In that an older Fender amp wired on an eyelet board is not PTP, but might be called "hand-wired," while "point-to-point" is that specific method of hand-wiring a circuit where components are for the most part soldered to each other, directly to tube sockets, etc. Frequently using small terminal strips as bridges between components. Typified perhaps (in the olden days) by this Supro Comet:

    [​IMG]


    Or something even more serious like this Maggie 440, replete with reverb and vibrato:

    [​IMG]

    Or am I all wet on this one - I'd be pleased to be corrected by someone as knowledgable as Mr. Aiken!
     
  12. reaiken

    reaiken Member

    Messages:
    1,775
    Joined:
    Jan 4, 2002
    Location:
    Greenwood, SC
    You are correct. "True" PTP is an amp wired with the components suspended from the tube socket pins or sometimes terminal strips. Some people call tag boards or turret boards point-to-point, but they are really not, if you want to get technical about it. It is a semantics issue, as both styles are equally "repairable", but turret boards or tag boards are usually easier to troubleshoot and follow a layout/schematic.

    I generally lump all styles of turret/tag/terminal strip amps into the "PTP" category, as opposed to PCB amps.

    Randall Aiken
     
  13. voojo

    voojo Gold Supporting Member

    Messages:
    3,424
    Joined:
    Apr 14, 2007
    Location:
    Wisconsin's Northwoods!
  14. SgtThump

    SgtThump Member

    Messages:
    6,887
    Joined:
    Jun 23, 2004
    Location:
    St Louis, Missouri
    That's not what I hear... :AOK
     
  15. 2x6L6

    2x6L6 Supporting Member

    Messages:
    466
    Joined:
    Mar 3, 2004
    Location:
    Talkeetna Mtns.
    Good explanation - thanks. I must say, as a hobbyist (prolly true for pros also...???), I have learned a lot working on my little rat's nest PTPs but man, oh man they are migraine-makers compared to a nicely laid out tag or turret board.
     
  16. lannyhall

    lannyhall Member

    Messages:
    1,278
    Joined:
    Nov 1, 2003
    Location:
    Texas
    The reason I have not grabbed any circuit board amps as keepers it that they will be far more difficult to get replacement parts for when something significantly bad happens to them, like a broken or burnt board. A good non-PCB amp will be salvageable. I'm not talking about making it really easy on the amp repair shop; I'm talking about being able to repair a broken PCB. Some of those amps have the knobs and/or tube sockets as part of the board. :(

    I can't imagine my kids being able to have a truly messed up PCB amp repaired forty years from now. I can see getting my '68 Fender Twin Reverb, blackface Princeton Reverb, or my Badcat Blackcat 30R repaired then.

    Some of the PCB amps sound great, but I prefer an amp that isn't disposable.
     
  17. revgsmall

    revgsmall Member

    Messages:
    2,088
    Joined:
    Jan 17, 2002
    Location:
    Sheridan, WY.
    In all fairness the article explains the tag board design as well and did say its not "true" PTP.
     
  18. Steve Dallas

    Steve Dallas Supporting Member

    Messages:
    8,196
    Joined:
    Feb 22, 2005
    Location:
    Surrounded by Idiots
    I haven't read the article. But I do have an opinion :)

    Any method of construction can be excellent or poor depending upon the execution. There are many reasons why one may be chosen over the other by the builder, but as long as the decision is well-executed, the amp should sound good and be reliable.
     
  19. riffmeister

    riffmeister Gold Supporting Member

    Messages:
    16,477
    Joined:
    Jan 4, 2003
    Location:
    near Philly
    Right, it's all about execution......and quality of parts used.

    The other thing I'd add to this discussion is that complicated circuits, for example a 4-channel amp with lots of bells and whistles on each channel, are usually prohibitively difficult to do in the PTP realm.
     
  20. FFTT

    FFTT Member

    Messages:
    28,439
    Joined:
    Apr 6, 2007
    Even where some of the finer amps use aircraft spec PCB construction, you still can end up with costly headaches down the road trying to replace
    proprietary boards or components.

    At least with a well built hand wired circuit, you can usually find someone
    local who can repair any problem that comes up with commonly available
    components.
     

Share This Page