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Stephens Tru-Sonic 15" woofers in Ampex Signature

Discussion in 'Tube Audio' started by Omegaman, Sep 18, 2018.

  1. Omegaman

    Omegaman Ultra Super Member

    Messages:
    2,873
    Location:
    Scottsdale, Arizona
    I am restoring this Ampex signature console

    I first posted about it in D&S
    http://audiokarma.org/forums/index.php?threads/phx-cl-empty-console.836337/

    The cabinet was empty except for the secret treasure inside
    There were no identifiable markings

    It was probably an early one since it has the Stephens 15" Tru-Sonic drivers

    The Grills were easily removed with the proper instruction

    Dimpled dust caps (There goes pristine)
    I don't know what the other speakers are

    Once I pull the drivers I'll know
     

    Attached Files:

    Last edited: Sep 18, 2018

     

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  2. Omegaman

    Omegaman Ultra Super Member

    Messages:
    2,873
    Location:
    Scottsdale, Arizona
    Here is the cabinet after a refinish session
    DSC07743.JPG DSC07745.JPG

    The top I hit hard with chemical stripper and 0000 steel wool and 400 sandpaper
    Not perfect but much better
     
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  3. Omegaman

    Omegaman Ultra Super Member

    Messages:
    2,873
    Location:
    Scottsdale, Arizona
    I decide to temporarily remove the doors for best access
    DSC07752.JPG

    The grills come off much easier with the hinges out of the way

    If any fellow AK'er has a Signature and can provide a picture of the component opening in original configuration (Tuner/Pre-amp) Could you please post it so I can get an idea of what I have to do

    I am interested in how they mount into the cabinet

    I believe there should be a small panel of wood on each side of the components

    DSC07748.JPG

    Here is the piece of veneered plywood that was used. It screwed into the existing holes and used flat head screws
    DSC07749.JPG DSC07750.JPG
     
    Last edited: Sep 19, 2018
  4. Dswankey

    Dswankey Super Member

    Messages:
    3,672
    First of all congrats!!!!, and I look forward to your completed restoration. In my Crescendo, it has metal brackets on the interior sides. The tuner/preamp slid in. I'm not sure if that would be the same for yours but I thought I would share. I'll make an effort to take a pic to give you an idea hopefully in the next day or 2
     
    Last edited: Sep 19, 2018
  5. Dswankey

    Dswankey Super Member

    Messages:
    3,672
  6. CoastinHome

    CoastinHome Member

    Messages:
    73
    Location:
    San Diego
    Omegaman,

    Thanks for the pictures!

    Glad the instructions were helpful for removing the grilles. One of mine is too tightfitting to be able to release the catch from the outside. I’m thinking I will have to carefully spread the weave on the grille cloth and push a tool through the grille cloth to release the catch. I would have to do the same in a second location to be able to get some light in there. Not happy about the idea so I have left that grille in place for quite some time until perhaps I find a better solution.

    As far as your dimpled dust caps, except for the creases you might be able to pull them closer to the original shape with the suction of a vacuum cleaner. You might need to add a PVC coupling so that you are only contacting the paper cone. Not sure if that’s worth the effort.

    Regarding the original frame around the preamp and tuner, these are two solid blocks of presumably walnut, 1.25” thick. The material should be the same as the two rails to the sides of the drawers. They are likewise glued in place. The height is to the top of the cabinet which on mine is 9.125 inches. In your pictures it looks like the lower rails were cut slightly lower (as the wood appears unfinished) -- so they may require a special cut so as to close the gap with the lower rails without interfering with the upper drawer. They are just shy of 3 inches wide (2-15/16”); the resulting opening for the preamp and tuner is right at 15”.

    Lot of words but a picture should help...

    Signature Preamp Tuner LH Mount.JPG

    Thought I would comment also on the doors you removed in case you were thinking of refinishing them:
    The finish on my doors were a good match for the rest of the cabinet prior to stripping the cabinet. After removing the old finish the top of the cabinet is absolutely gorgeous walnut - now with an oiled finish. When I stripped the doors, however, I found that their frames are A much different wood. They are a light colored hardwood - something like Hickory - which got its color match from the semi-transparent varnish (etc.) used. The wood doesn’t accept stain very well and will require special effort (perhaps the addition walnut or rosewood veneer to the faces of the frames) to look like the rest of the cabinet. Everything else seems to be walnut or walnut veneers.

    Hope this helps!

    Interested in your comments on before/after listening tests or other experience you have in recapping the crossovers.

    Bob
     
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  7. Dswankey

    Dswankey Super Member

    Messages:
    3,672
    Great pic!!! @CoastinHome

    Also note the arrow I added to your picture. That is where the bottom of the preamp locks (for lack of a better word) into place.

    Signature Preamp Tuner LH Mount.JPG

    Pic from the web

    30_1_b.jpg
     
  8. Omegaman

    Omegaman Ultra Super Member

    Messages:
    2,873
    Location:
    Scottsdale, Arizona
    That is what I was looking for. The mounting of the two units

    I won't refinish the doors, I just need them out of the way for awhile

    I'll pull the crossovers this weekend and Ohm out the drivers

    I'll listen to the speakers prior to crossover recap

    The dimples don't bother me

    Thanks for all the help
     
  9. bean_counter

    bean_counter Active Member

    Messages:
    272
    Location:
    Oswego, IL
    I have found this on the Acousti-Craft consoles I have worked with. A mix of woods, and a fairly thick colored varnish to match things up. Plywood top panels with routed hardwood edges tacked on, can be a trick to cosmetically repair scuffs that are on both pieces.
     
  10. Leland47

    Leland47 AK Subscriber Subscriber

    Messages:
    2,507
    Dswankey's pics above are pretty much what was in mine too.

    Mine had a couple spacers to shim it out on one side to make it fit. (the bracket to mount the tuner and preamp.)

    The French Provincial cabinet must be shorter than yours....as the 2 units barely fit in with just the 1 drawer.

    My cabinet is still sitting on my sun porch....
    I'd be glad to take some measurements is you need them.

    Mine had the MPX mounted upside down, behind the tuner.
     

    Attached Files:

  11. Omegaman

    Omegaman Ultra Super Member

    Messages:
    2,873
    Location:
    Scottsdale, Arizona
    Thanks for the Audio Karma responses

    More detailed cleaning of the insides
    Zen and the Art of restoration

    I used a soft Venetian horsehair brush (I made that up) and air can to clean the driver cones, dust caps and surrounds

    I cleaned and anointed the hinges and roller slides with oil and balm (grease) and sweetened the cabinets with frank's incense ( a religious experience)
    Gun metal bluing
    DSC07758.JPG

    Grill cloth cleaned
    I use Resolve carpet/upholstery foaming cleaner on the grill cloth
    The top measures 64" x 20 ". I might order a glass top for it
    DSC07759.JPG

    Nice and clean and smell free

    Interesting that the reverse screws that mount the mid-range interfere with the grill cloth frame slightly. I had to whittle two small channels in the wood frame so the screens mounted flush. The screens have cut outs for the woofer so they only fit on one way
    DSC07761.JPG


    I think the 1.25" thick blocks of wood on each side of the opening are 1.25" deep so that the components are recessed pretty and the door can close

    There is a 1/16th lip on the side posts next to the upper drawer so that the upper drawer will clear the bottom of the blocks (after installed) when the draw is moving

    The opening is 20.75" - 15" for the componets = 5.75" / 2 = 2 15/16ths"

    So I need two pieces of period matching walnut wood 9" high, 2 15/16th wide and 1 1/4" deep

    Here is one that looks like it should match mine
    a2_ampex.jpg


    Next I'll do the back
     
    Last edited: Sep 22, 2018
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  12. CoastinHome

    CoastinHome Member

    Messages:
    73
    Location:
    San Diego
    Omegaman,

    You do beautiful work. It’s great to see one appreciate the quality of this cabinetry enough to piece a console back together. Of course the intact top-notch speakers were a great head start!

    I started with a Barzilay (K61B) and after seeing the quality of construction of a gutted 1958 Ampex Signature cabinet I jumped ship and decided to build a custom hi-fi based the Ampex cabinet.

    Still interested if you find any indication of when (etc.) the cabinet or system was originally constructed. In addition to the serial number plate there are quality control stampings several places within the cabinet. Attached are some pictures from one of the two empty cabinets I acquired. This one has a hand drawn stamp from the back of one of the drawer slide stays. Wasn’t sure if someone was being funny or just didn’t have their stamper - but no reason to believe that it’s not original.

    You were commenting on fitment of the grilles. Along those lines note on the last photo below the handle mounted in the middle of the speaker baffle. This seems to (intentionally or otherwise) act as an additional support to the grille. The grille sits right against it and flexes slightly around it as the corner catches are engaged. Some of the units I've seen have this handle wrapped in tape.

    Thanks for your posts… It sounds like you are mostly doing a stock retrofit so overall dimensions perhaps won't be so important -- but let me know if you are interested in an engineering layout of the cabinet as I took the effort to measure and draw the entire cabinet in MS Visio.

    Bob
     

    Attached Files:

    Last edited: Sep 22, 2018
  13. CoastinHome

    CoastinHome Member

    Messages:
    73
    Location:
    San Diego
    re: <<The screens have cut outs for the woofer so they only fit on one way>>

    Oh... then the screens are different as well. (Screens = the metal frames that the grill cloth is wrapped around, right?). Those that I've seen are symmetrical open mesh -- they are interchangeable between left and right and can be swapped top for bottom as well. Interested in adding pictures of this variation to my "recognition guide".
     
  14. CoastinHome

    CoastinHome Member

    Messages:
    73
    Location:
    San Diego
    re: <<So I need two pieces of period matching walnut wood 9" high, 2 15/16th wide and 1 1/4" deep>>

    YMMV but mine measures at 9-1/8"H.

    ("Measure twice...Cut once" ... as we learned in HS woodshop o_O :)
     
  15. CoastinHome

    CoastinHome Member

    Messages:
    73
    Location:
    San Diego
    re: <<Here is one that looks like it should match mine.>>

    The actual cabinet pictured is one of the two empty cabinets in my collection. The Newport Beach seller wanted $2600 for it a few years ago and turned down my offer of $1200. His ad emphasized the desire to keep it intact - but he ultimately sold it for $1000 to a party who promised not to part out his uncles' stereo -- and then promptly did so down to the last Telefunken 12AX7. The seller did not include with the sale the box with the original accessories and invoice.

    After the buyer did his dirty deed I ultimately took a long drive and paid $25 for the completely bare cabinet and refinished it nicely. It sits empty as a work table of sorts -- while awaiting the eventual installation of rack rails in the 19 inch openings where the speakers were originally installed. Unfortunately in the interim the seller tossed the box of accessories -- as well as the original invoice which was part of his advertisement.

    The only bright side to this story is that after continuing to look I ultimately found a nicer unit to restore and keep intact as my living room heater.

    Oh...and that the cabinet didn't end up in the landfill! :(
     

    Attached Files:

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  16. Omegaman

    Omegaman Ultra Super Member

    Messages:
    2,873
    Location:
    Scottsdale, Arizona
    Here is the one side of the speaker that was untouched

    DSC07764.JPG
    The first pink insulation was wrapped in a circle and put in as the last piece before back panel
    Once the circle of pink was removed, there were some pieces stuffed in place

    And that white material. I don't know if it is cotton or glass? ITS SPUN GLASS LIKE COTTON CANDY.. IT DOES NOT BURN
    Wear gloves and mask

    placed purposely
    It is stuffed to the bottom
    I did not remove it all and I found sand
    DSC07765.JPG
    That label says authentic Jensen
    DSC07767.JPG
    I cut the mid range dust bag but there was no sticker so I taped it back together
    I really don't want to pull the drivers because they were set in the factory wise


    The crossover
    two coils and four caps

    40mf
    25mf
    4mf
    25mf

    all 50v NP

    Dayton precision caps on order

    DSC07768.JPG

    For comparison here is the crossover from my 1961 Ampex 7208 with Ampex Audio 12" woofer, 8" sealed Utah mid, and EV T35B tweeter
    DSC03564.JPG
     
    Last edited: Sep 23, 2018
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  17. Omegaman

    Omegaman Ultra Super Member

    Messages:
    2,873
    Location:
    Scottsdale, Arizona
    Factory fit-and-finish issue

    The left (or right) speaker back plate was installed backwards

    DSC07773.JPG DSC07774.JPG
    With the plate oriented correctly
    The screw holes don't align
    I will counter sink the screws and drill new holes
    And paint both plates the same color or stain to match
    DSC07777.JPG
    Inspector 57 - Please report to the QA office

    One other thing - When did they change from flat head screws to cross head screws?
    The console is all flat head screws, screws from my 61 console all had cross head screws

    Also, I ohm'ed out each driver and got positive readings 11 ohm, so no apparent open coils - which is nice

    One more thing, the pilot lamp voltage is 3.15VAC
    Can I just use a GE47 6.3 there?
     
    Last edited: Sep 23, 2018
  18. CoastinHome

    CoastinHome Member

    Messages:
    73
    Location:
    San Diego
    Thanks for sharing the detail and photos.

    Really don’t see any problems rising to the level of incorrectly installed panels on my cabinets. The most recent of the three cabinets has the model/serial number tag tacked on with the staple gun rather than the nice bronze rivets. That’s about it -- other than the tight fit of one of the grilles.

    That your cabinet has a speaker back installed inside out is pretty blatant. Inspector 57 should’ve been fired for that one. Perhaps he was the one who let Leland’s console out the door with one woofer disconnected. He would’ve been at home at the authorized Ampex repair facility in Los Angeles which cross-threaded incorrect screws into my preamp and immortalized countless other symptoms of his ineptitude at repair.

    The right speaker lower rear panel is where the multiplex unit was mounted on one of these. This is a 1961 model 8102 which is shown stripped bare in my above post. I can give you the location of the screw holes -- but it appears from your older posting that you have a different multiplex unit with a narrower footprint than the Ampex 510/520.

    What do you know about your multiplex unit? Any indication that it’s a Fisher-for-Ampex?

    Ampex Signature Los Angeles 4.jpg
     
    Last edited: Sep 23, 2018
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  19. Omegaman

    Omegaman Ultra Super Member

    Messages:
    2,873
    Location:
    Scottsdale, Arizona
    The multiplex I am using is a Pilot
    The original unit did not have the MPX adapter

    When I got the original console, I was ready to leave when the guy said "Wait, let me get the tapes"

    He was talking about the 500+ tapes 7", 5", 3" mostly 7"
    The owners wife worked for Scotch and he loved to record
    FM Mono onto the 4 track tape deck
    4 full tracks of slow mono recording

    Hundreds of tapes
    fully notarized on the box in super detail

    Incredible effort

    He wore the tape deck out

    I found some old parts and pieces and needed screws
    DSC07769.JPG DSC07770.JPG DSC07771.JPG
     
    Last edited: Sep 23, 2018
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  20. CoastinHome

    CoastinHome Member

    Messages:
    73
    Location:
    San Diego
    I was trying to visually identify your mid range drivers to take some of the mystery out of that. What I can see of the driver frame suggests that it might be a some variation in a Jensen P8 series Alnico. If so, the model designation and/or control numbers would likely be stamped in ink on the side of the square magnet structure. You might do a Google search for the model number of the tweeter and look for Jensen bookshelf speaker kits which include that tweeter to see if the associated midrange looks familiar. It would be a 16 ohm driver.

    The empty cabinet in my earlier post (where the baffle plate is shown) formerly housed a pair of 15 inch Trusonic woofers, a pair of Trusonic 80FR midrange drivers, and a pair of ElectroVoice T35B tweeters. It was packed as shown with only the white cotton candy. This material seems to be spun glass shredded and mixed with silica -- so the sand you are finding in the bottom of the box must have settled out of the cotton candy. Mine didn’t have any of the pink fiberglass wrap.

    I am ever more confused about which drivers were supplied at what time and whether any were considered upgrades to the standard configuration.

    The 1959 model 8002 above had dual 12" Ampex-branded drivers on each side (with "Ampex" 8" midrange and EV T35B). The (advertised as a "1961") model 8102 above originally had Trusonic 15 inch woofers (with Trusonic 80FR's and EV T-35B's). My 1961 model 8202-2 appears to have Altec Lansing 803B 15" woofers, "Ampex" by EV midranges and EV T-35B tweeters. I've seen three other configurations - including yours.

    My best guess on model designations:

    8xxx = Signature
    x0xx = 1959
    x1xx = 1960
    x2xx = 1961
    xx0x = Garrard changer (RC-88 MkII)
    xx1x = Garrard 301
    xx2x = Garrard changer (Type A)
    xxxx = 30W Amplifiers
    xxxx-2 = 40W Amplifiers (solid state rectifier)

    These are only guesses to be tested.
     
    Last edited: Sep 24, 2018

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