Tweakers' Asylum

Good question.

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cheap-Jack

(A)

In Reply to: Why do you want to potentially trash a unit as good as a Herron? posted by Bob Rex on April 24, 2007 at 08:27:34:

Hi.
Herron HTPH-1MC is so far one of the finest tube-preamps I ever auditioned. So why trash it?
I don't like the sound of its replacement model with those digital display gadgets though.
c-J

Follow Ups:

"Trash" it? My my, you two are being awfully tough on Pauly. Surely both of you understand that products... - jeffreybehr 09:11:47 04/24/07 (14)
...even as good as Keith Herron's are built down to a price. If Keith used the absolutely best-sounding parts money could buy, the preamp might cost $30K!
Replacing coupling caps with other high-quality caps will NOT "trash" the preamp or its sound. Probably it'll CHANGE it, and MAYBE those changes will be improvements.
Pauly, I suggest you contact Keith Herron and ask him to identify the coupling caps by values and locations. He might even be willing to share with you some of his experiences with different caps or supply you with a schematic diagram.

-------------------------------------------------------
Tin-eared audiofool and obsessed landscape fotografer.
http://community.webshots.com/user/jeffreybehr
- thanks for the suggestions - Pauly 14:27:39 04/24/07 (3)
  You are on point, the Herron is an excellent product, but made within a budget. It has not got the best parts money can buy - not by a long shot.
  I am thinking of replacing coupling caps, a stereo pair at a time and auditioning each change. If the change is a step backwards, I can simply replace the OEM parts.
  I'll contact Keith although I believe he does not like hobbyists soldering away in his equipment.
  Regards
  Paul
  - "...although I believe he does not like hobbyists soldering away in his equipment." Yup. Lots of designers feel... - jeffreybehr 00:18:24 04/25/07 (2)
    ...that way.
    But that doesn't mean he won't help to some extent.
    BTW you should seriously consider the SoniCap Platinum, Glowacki's Teflon-alloy foil-and-film cap. I and others feel it's about as good sounding as money can buy, and it's less expensive than the VH TFTFs.
    -------------------------------------------------------
    Tin-eared audiofool and obsessed landscape fotografer.
    http://community.webshots.com/user/jeffreybehr
    - Re: "...although I believe he does not like hobbyists soldering away in his equipment." Yup. Lots of designers feel... - sherod 21:29:53 04/25/07 (1)
      I have read that the new leader of teflon caps is the V-cap TFTF. Have you had an opportunity to compare to the Sonicap Platinum yet?
      - No. (NT) - jeffreybehr 22:32:38 04/25/07 (0)
        
        In Reply to: Re: "...although I believe he does not like hobbyists soldering away in his equipment." Yup. Lots of designers feel... posted by sherod on April 25, 2007 at 21:29:53:
        
        .
        -------------------------------------------------------
        Tin-eared audiofool and obsessed landscape fotografer.
        http://community.webshots.com/user/jeffreybehr
- This is not replacing coupling caps that simple. - cheap-Jack 11:46:41 04/24/07 (9)
  Hi.
  Read Paul's post again.
  He gave me the impression of modifying the "passive RIAA section" by
  avoiding "any couplers".
  Depending on the circuit design (hence the poster asked for Herron's schematic), removing any coupling capacitors (I assume) may affect the overall balance & accuracy of the RIAA EQ. This is not any tweaker should do without making very sure from the schematic if such coupling capactors should be removed.
  Bob wanted to warn the poster such RIAA EQ modification may 'trash' the amp & he also suggested to consult the amp's designer first.
  To this, I totally agree.
  This Herron phono pre-amp sounds superb when matching with other equally fine quality components. So why need to modify it?
  My question is: is there anywhere along the audio chain that needs to be improved in the first place than modifying the phonostage?
  Nowhere in the post hinted replacing any coupling caps. Only :"to avoid" was clearly stated. It is Bob & your assumption only which may not even the case.
  A question to you, if the coupling caps in the "passive RIAA section" were polypropylene PP, which are pretty commonly used in RIAA network coupling, what "other high quality" caps would you suggest?
  Tweaking is the name of this forum. But it got to work out with logics & common sense. RIAA EQ is the last place of a phonostage I want to modify despite I built/upgrade a few.
  Which would be a tougher experience? Screw up the fine phonostage or a word of caution to think twice?
  c-J
  - CJ - I think you should read my post again - Pauly 14:22:21 04/24/07 (6)
    How you make the assumptions you do I am not sure. To help you, let me repeat verbatim
    "I want to avoid any couplers in the passive RIAA section."
    a�void /əˈvɔɪd/ Pronunciation Key �verb (used with object)
    1. to keep away from; keep clear of; shun: to avoid a person; to avoid taxes; to avoid danger.
    2. to prevent from happening: to avoid falling.
    3. Law. to make void or of no effect; invalidate.
    4. Obsolete. to empty; eject or expel.
    Regards
    Paul
    - That's your wrong use of English, my friend. - cheap-Jack 08:32:43 04/25/07 (5)
      Hi.
      To "avoid" in this situation means to me "to empty, to eject or expel". So from what you wrote would mean to me you don't want any coupling caps in the "passive RIAA section".
      That would be a serious issue as coupling caps there got to have their function, e.g DC blocking, etc., that I can tell you once you find & post the schematic.
      But you actually mean to 'replace' them with other type of caps instead of "to avoid" them. So the way you wrote misled me.
      c-J
      - Actually that is "Void" (no "a") used as a verb. nt - clifff 03:24:40 04/26/07 (3)
        
        In Reply to: That's your wrong use of English, my friend. posted by cheap-Jack on April 25, 2007 at 08:32:43:
        
        Cliff, best just to ignore. - Pauly 12:59:57 04/26/07 (1)
        
        In Reply to: Actually that is "Void" (no "a") used as a verb. nt posted by clifff on April 26, 2007 at 03:24:40:
        
        I clearly state in my heading I want to upgrade my coupling caps, and then state further I want to avoid the couplers in the RIAA stage.
        One has to be quite dim to interpret my statement as me wanting to remove the RIAA caps ...
        Regards
        Paul
        
        Q.E.D. nt - clifff 13:42:00 04/26/07 (0)
        
        In Reply to: Cliff, best just to ignore. posted by Pauly on April 26, 2007 at 12:59:57:
        
        Generally, to "void" means to declare effectless. - cheap-Jack 07:56:50 04/26/07 (0)
        
        In Reply to: Actually that is "Void" (no "a") used as a verb. nt posted by clifff on April 26, 2007 at 03:24:40:
        
        Hi.
        We can void a contract, but we don't void a capacitor but we can "avoid" using one.
        c-J
      - My apologies that my English is not to your standard. - Pauly 14:50:39 04/25/07 (0)
        
        In Reply to: That's your wrong use of English, my friend. posted by cheap-Jack on April 25, 2007 at 08:32:43:
        
        In fact my English is so bad that it actually seemed to me that you think I am your friend and you think I need to provide you with a justification for me wanting to modify one of my own amps!
        Wow, what a misunderstanding.
        Regards
        Paul
  - Re: This is not replacing coupling caps that simple. - Bob Rex 13:53:38 04/24/07 (1)
    To expand on Jack's comments, from what I remember Keith held some pretty tight tolerances in the RIAA section. I believe he even recommends contacting him before key tubes are swapped because the circuit is built around a specific mu and gain. Now if the circuit is that precise, why muck around with success? Just so you can drop in a couple of special caps you've been itching to try??
    Besides, the layout of the circuit is very clean - this isn't a point to point wiring job where there may be space for physically larger parts. What deficencies are you trying to address?
    I'm not saying that the piece is above reproach (it's pretty close) but just think about the whys and wherefores of what you are doing.
    - Re: This is not replacing coupling caps that simple. - Pauly 14:50:02 04/24/07 (0)
      Hi Bob
      I appreciate your concern. I have upgraded a number of amps before ... although I always had the circuit diagram available. I don't now and that's what I'm asking for.
      I am not thinking of changing the RIAA caps. I honestly did I wasn't, so I am not sure how that came about.
      From what I could see the couplers are 0.22uF caps and there is plenty room for a V-Cap/Dynamicap sized coupler. I would like a circuit diagram though to be 100% sure it is the coupler cap I am looking at.
      The Herron is a good piece. I want a little better. I can spend $600 on high quality caps or $10,000 on an Aesthetix. I don't really have $10,000 to play with now ...
      If I put in the new coupling caps and they sound bad/worse, I can always revert to OEM. As I told Jeffrey, I do one stereo pair at a time and audition. No biggie.
      Regards
      Paul