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Is there a 'Blackface' type ~15w clone?

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  • #16
    Originally posted by MWJB View Post
    Hi Stokes,

    That 60mA rating on the B+ winding is an AC rating, not DC (had the same reservations & checked with mfr). Previously was in a 5E3 type build which even ran 6L6s (100mA draw) with no issues.

    Cheers, Mark.
    Very good,I was wondering about the 25watt rating with only 60ma's on that HV winding.

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    • #17
      Originally posted by The Captain View Post
      Forgive my naiivity, but can someone point out why the BF Princeton's tone config can't be added to the 5e3? say turning the normal vol pot into the bass pot, and so the tone pot as the treble? (or suchlike) ie single channel with bass, treb and vol- as opposed to 2 channel's tone, vol and vol..?
      You have 250k pots in the BF Princeton,the 5E3 has 1M pots,it could be done,but the values of the components would have to be adjusted.There is a site that has a tone scaling section,I dont recall where I saw it,maybe somebody can point you to it.

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      • #18
        Originally posted by The Captain View Post
        Terrific.. that sounds a spot-on idea. Id like to know your opinion of my PT for this application Mr.Stokes http://www.torresamps.com/images/trans-25.gif its perhaps not ideal, but, using the site below as a build basis the clips do sound VERY promising and fendery using just a hammond 270FX (270v-0-270v presumably), ie hopefully not too dissimilar to mine.. & fwiw a 125?SE and a 5U4 is it? here: http://jameshadfield.com/Princetone.html

        Grateful for any input of course, Captain.
        Is this the PT you used in the 5E3?
        Did you also use a NOS 5Y3GT?
        What output transformer did you use for the 5E3?

        Why I ask now is that I am getting the feeling maybe you never built a real 5E3 clone anyhow so you really don't know what one sounds like.
        Bruce

        Mission Amps
        Denver, CO. 80022
        www.missionamps.com
        303-955-2412

        Comment


        • #19
          Hi Bruce,

          The Captain used a Weber PT to start with (484v on the plates uncorrected - I've seen original tweed Deluxes run higher). It burned up. The replacement Weber ran very hot & high voltages. I offered a spare 2nd hand PT that admittedly ran lower B+ than a real 5E3 but as the Captain has noise issues with neighbours I figured a little earlier breakup wouldn't hurt.

          Throughout the various PT's The Captain had issues with the tone.

          But your point is a good one, when setting out to build your first amp a tonal reference is a must to ensure it really is doing what it's supposed to. Just ensuring voltages are ball park and connections are correct is not always enough. Better quality kits, with instructions, take out a lot of the guesswork. A bit more expensive? Yes, but when your tearing out your hair in frustration you'll be wishing you'd spent that bit extra.

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          • #20
            Bruce I do have this in the 5e3 at the mo, but have until recently had a 'proper' ish voltage Weber PT in (reson was the weber was hot, but it seems they just do that anyway). Fwiw now the chassis is just warm yes- soundwise though its only mildly flatter, otherwise its as annoyingly bassy as ever, hence I must have bass and treble pots on a 5** build or its really tonally useless to me. Im trying to figure out the BF Princeton applied to the 5e3 before I bin it, but its doing my head in figuring it out!

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            • #21
              Good point there. I can believe better PTs such as Missions will sound altogether better, but I think I just made the innitial mistake of plumping for the 5e3- soundclips from internet etc, never give any idea of the lower tones- and have spent lord knows how long thinking I had a prob when I didnt! Now Imho 5e3s were designed in the 50s for single coils only (obviously) but WITH an extra dose of low end to 'fill' the stage as it were, perhaps filling in, to an extent, for the bass register too. Therefore with my SG its all wrong, unless I can specifically alter its tone with 2 tone pots..

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              • #22
                Mount the tone caps and treble slope (100K) on the pots, then you can visually trace where they need to be, doubt you'll find room on the board anyway. Use the 2nd half of V1 as a tone recovery stage a la BF Princeton Reverb and every other BF amp apart from non-reverb Princeton.

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                • #23
                  Originally posted by stokes View Post
                  You have 250k pots in the BF Princeton,the 5E3 has 1M pots,it could be done,but the values of the components would have to be adjusted.There is a site that has a tone scaling section,I dont recall where I saw it,maybe somebody can point you to it.
                  Well, just made me think, on the tone stack calculator there's the james amps tonestack which has a one meg pot and a 470, may be it would be nice to do a baxandall tonestack in your tweed.

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                  • #24
                    This is a great plan to crack on with on the 5E3.

                    A closer look at the BF Princeton Rev shows 340v, 340v along to the rectifier pins 4 and 6: http://i102.photobucket.com/albums/m...164_layout.gif

                    Now then, as my unused Weber PT has 680v secondaries (6.3v filaments, 5v other 2) could this be used to clone the whole shebang for a future project- or am I missing a trick.. I saw Weber DO use this exact PT for their clone of the circuit BUT using the PTs 'other pair' of 540v 2ndaries (the layout differs by using a 'WU4GB' recifier/ slightly differing 6v6gt wiring but otherwise exactly the same). Would anyone know why the 540v prefered, or any reason why I couldnt use the PT with the 680v pair as per the original above layout? (I did try these lower 540v 2ndaries as advised to run the PT cooler in the 5E3, but alas I got no sound at all).

                    Thanks for any ideas, Captain.

                    Comment


                    • #25
                      Originally posted by The Captain View Post
                      Bruce I do have this in the 5e3 at the mo, but have until recently had a 'proper' ish voltage Weber PT in (reson was the weber was hot, but it seems they just do that anyway). Fwiw now the chassis is just warm yes- soundwise though its only mildly flatter, otherwise its as annoyingly bassy as ever, hence I must have bass and treble pots on a 5** build or its really tonally useless to me. Im trying to figure out the BF Princeton applied to the 5e3 before I bin it, but its doing my head in figuring it out!
                      Yes I recall the other threads now.
                      OK, a blackface Princeton is a very similar amp to a 5E3 but the Princeton uses the second triode of V1 to recover audio from the treble-bass-mid tone section and the other triode of V2 to make vibrato.

                      The major differences are the tone stack and the Princeton is fixed bias while the 5E3 Deluxe is cathode biased.
                      The phase inverter of the Princeton is almost the same as the tweed Deluxe so you can build a great sounding amp with two power tubes and two preamp tubes.
                      Bruce

                      Mission Amps
                      Denver, CO. 80022
                      www.missionamps.com
                      303-955-2412

                      Comment


                      • #26
                        Ive tried applying a Princeton Rev tone circuit to the 5E3 now, but alas I get just a loudish 'BRRR' from speaker. Can anyone spot a faux-pas here? thanks

                        http://i102.photobucket.com/albums/m...Picture326.jpg

                        go to..

                        http://i102.photobucket.com/albums/m...Picture327.jpg

                        In meantime Im thinking to just redo a BF fixed bias circuit entirely, & ideally with my PT- if anyone could remind me (lost track sorry) if its at all suitable for the Princeton Reverb circuit: (PT again http://www.torresamps.com/images/trans-25.gif). Cheers folks
                        Last edited by The Captain; 07-13-2007, 12:26 AM.

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                        • #27
                          Cant tell anything from the pictures,but I assume you are now only using one channel,in other words only one half of the first preamp tube is being used.In order to use both halves,or 2 channels, you would need 2 complete tone stacks,one for each half of the first tube.If you are trying to use one channel with the original 5E3 tone circuit and one with the Princeton Rev,it wont work.As for the PT,it will work for the BF circuit,but the voltages wont be exactly as the schem shows.

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                          • #28
                            Originally posted by stokes View Post
                            Cant tell anything from the pictures
                            as per usual (I mirrored light up into pots for the shot too! hehe oh well). What I was trying was to single channel it adding a bass (L) and treb (middle pot) to the vol (R), to the V1/ V2 as the princeton reverb does. I shifted the dropping Rs from 4.7k and 22k to 1K and 4.7K too, amongst other wiring tinkerings- none done as guesswork- I was helped again patiently by MJWB to get the setup. Maybe its too long a shot to convert this way; perhaps its just telling me 'enough already with the 5E3'.. beaten me black and blue so it has.

                            So thanks Mr. Stokes- a fresh start is needed/ new circuit entirely. Can you point me twds a rectifier for above PT used for a BF Princeton Reverb ie, do I stay with the 5U4GB as the fender schem/ layout, try a weber WU4GB, or maybe I need a 'match'/ another for this PT (with a 125E fwiw).

                            Muchos muchos, Captain.

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                            • #29
                              Captain,

                              Where does the red wire from the centre tab of your volume pot go? Should go to V1 pin 7.

                              Wiring with a BF tonestack between V1a & V1b (using both halves of the first preamp tube) will work fine.

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                              • #30
                                OK spottedan error.

                                The yellow wire from coupling cap at V1, 1 should go to the free end of the 250pf cap on the treble pot. From this same junction the 100K resistor should then go to the junction of both the .1uf & .022uf caps on the bass pot.

                                You currently have the 100K in series with the yellow wire to the 250pf.

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