Greetings Forum members
1. Trace Elliot Tramp, same super tramp preamplifier pcb but power amp simplistic IC by phillips called TDA1514A, nine pin single inline plastic casing heat sinked, isolated.
2. Posted questions on super tramp thread nobody answers at all.
3. Unbutchered all of the lame repairists pcb landings and traces, using japanese five minute expoxy and cannibalized landings and traces lifted off from abandoned laserprinters pcb's.
4. lesson learned, use epoxy to affix replcmnt landings and traces, compression mandatory during cure, interface surface prep paramount, winner during reinstlln discrete components and strength too for cabinet vibration fatigue of welds.
5. replaced poweramp ic called tda1514a bought from china ebay, genuine phillips, but there's questionable behavior.
6. during ps cap forming (brand new) variac brought up line ac gradually, four equally spaced increments with pausation five minute intervals, there was dc thru the speaker (dummy resistor 5.1 in lieu of 4 ohm), enough to warm that ten watter sandblock.
7. at equilibrium steadystate, dc speaker stable 100millivolts dc, BAD? why not ten times smaller at 10millivolts?
8. after ps new caps broken in, instantaneous powerup (w/o variac) has that momentary (half second) speaker DC hum (dc is quiet right?). so shutdown and measure voicecoil integrity, its ok.
9. tda1514a has mute function but elliot doesnt utilize. is this why tda1514a has capability of mute? so we could time delay mute engaged until that half second during cold powerup elapses, so tda1514a doesnt feed dc to the spkr? or is the china genuine tda1514a bogus?
10. i am uncomfortable with the cold powerup brief dc to spkr, it is a sin to dc the voice coil, no matter how brief. i am uncomfortable with the variac powerup tda1514a applying spkr dc, enough to warm that sandblock enough to feel it.
11. it plays, very well, pretty sassy signature (J112's multistaging build, contour, rebuild). customer put in a small magnet 12" eight ohm, flat felt twentyfive cent coin sized dust cap over voicecoil, accorddian pleating fabric paper surround, so its pretty light duty for the tda1514a (40rms acoustically)
12. i sprayed that ace hardware store cleaner called bullfrog electronic cleaner corrosion blocker, all potentiometers access window, removed cliff jack switching tangs to rebend greater contact compression typical gremlin in any amp having switching cliffs. but i dont know whether bullfrog affected carbon tracks within those pots, i say this because i just cant center testpoint2, so i settled on 55percent rotation of the corresponding trimmer producing fourteen dc although the supertramp thread mandates (+1 for the fets foward) targeting fifteen which the trimmer wont dial in (max'd already)
13. this amp company changed hands, no help from them. i am ordering more china genuine phillips tda1514a ic's to investigate further why there's DC (!) during cold startup and or variac gradual cold startup. the dc rails are healthy plus thirty one and minus thirty, under quiescent load. preamp utilizes absolutely nothing of the minus rail, so why is the plus rail not dragged downwards?
14. remote footswitching error free, building a custom rightangle plug so user can reach behind and finger switch (boost/channel), micro slide switch epoxied onto interior right angle switchcraft three conductor (two switches capable, w/ led and dropping resistor).
15. diyaudio schematic provided by supertramp thread depicts dc rails plus minus 35 at utility line ac 119.4 (120), so existing rails are shy (31/30) under quiescent load. i did not remove preamp electrolytics to check values, but it is possible a preamp culprit is dragging energy down, only way to confirm is measure electrolytics out of circuit. plus there's tantalums on the cathode bias of preamp j112's (n channel jfet), i didnt test these out of circuit. can we say the pt from 1994 has oxygenated windings of copper? the ac legs measure exactly 25vac each leg, loaded, quiescent condition.
16. last, soldered SIP female header into the ps pcb using umbilical teflon silvered three inch wires (nine 24gage). this enables ease swapping out communist china genuine phillips tda1514a modules, no grease just TO3 thermal grey pad, and star lock washer compression fasteners. but does the added three inches react adversely as crosstalk aerial antennae? realize phillips intentionally distanced small signals from heavy signals insofar as SIP terminals.
17 your responses are welcome (amp sings sassy brit, esp chnnl2 snazzy rounded clipping jfet intrinsic behavior but is it right iaw elliot's designed intentions?)
1. Trace Elliot Tramp, same super tramp preamplifier pcb but power amp simplistic IC by phillips called TDA1514A, nine pin single inline plastic casing heat sinked, isolated.
2. Posted questions on super tramp thread nobody answers at all.
3. Unbutchered all of the lame repairists pcb landings and traces, using japanese five minute expoxy and cannibalized landings and traces lifted off from abandoned laserprinters pcb's.
4. lesson learned, use epoxy to affix replcmnt landings and traces, compression mandatory during cure, interface surface prep paramount, winner during reinstlln discrete components and strength too for cabinet vibration fatigue of welds.
5. replaced poweramp ic called tda1514a bought from china ebay, genuine phillips, but there's questionable behavior.
6. during ps cap forming (brand new) variac brought up line ac gradually, four equally spaced increments with pausation five minute intervals, there was dc thru the speaker (dummy resistor 5.1 in lieu of 4 ohm), enough to warm that ten watter sandblock.
7. at equilibrium steadystate, dc speaker stable 100millivolts dc, BAD? why not ten times smaller at 10millivolts?
8. after ps new caps broken in, instantaneous powerup (w/o variac) has that momentary (half second) speaker DC hum (dc is quiet right?). so shutdown and measure voicecoil integrity, its ok.
9. tda1514a has mute function but elliot doesnt utilize. is this why tda1514a has capability of mute? so we could time delay mute engaged until that half second during cold powerup elapses, so tda1514a doesnt feed dc to the spkr? or is the china genuine tda1514a bogus?
10. i am uncomfortable with the cold powerup brief dc to spkr, it is a sin to dc the voice coil, no matter how brief. i am uncomfortable with the variac powerup tda1514a applying spkr dc, enough to warm that sandblock enough to feel it.
11. it plays, very well, pretty sassy signature (J112's multistaging build, contour, rebuild). customer put in a small magnet 12" eight ohm, flat felt twentyfive cent coin sized dust cap over voicecoil, accorddian pleating fabric paper surround, so its pretty light duty for the tda1514a (40rms acoustically)
12. i sprayed that ace hardware store cleaner called bullfrog electronic cleaner corrosion blocker, all potentiometers access window, removed cliff jack switching tangs to rebend greater contact compression typical gremlin in any amp having switching cliffs. but i dont know whether bullfrog affected carbon tracks within those pots, i say this because i just cant center testpoint2, so i settled on 55percent rotation of the corresponding trimmer producing fourteen dc although the supertramp thread mandates (+1 for the fets foward) targeting fifteen which the trimmer wont dial in (max'd already)
13. this amp company changed hands, no help from them. i am ordering more china genuine phillips tda1514a ic's to investigate further why there's DC (!) during cold startup and or variac gradual cold startup. the dc rails are healthy plus thirty one and minus thirty, under quiescent load. preamp utilizes absolutely nothing of the minus rail, so why is the plus rail not dragged downwards?
14. remote footswitching error free, building a custom rightangle plug so user can reach behind and finger switch (boost/channel), micro slide switch epoxied onto interior right angle switchcraft three conductor (two switches capable, w/ led and dropping resistor).
15. diyaudio schematic provided by supertramp thread depicts dc rails plus minus 35 at utility line ac 119.4 (120), so existing rails are shy (31/30) under quiescent load. i did not remove preamp electrolytics to check values, but it is possible a preamp culprit is dragging energy down, only way to confirm is measure electrolytics out of circuit. plus there's tantalums on the cathode bias of preamp j112's (n channel jfet), i didnt test these out of circuit. can we say the pt from 1994 has oxygenated windings of copper? the ac legs measure exactly 25vac each leg, loaded, quiescent condition.
16. last, soldered SIP female header into the ps pcb using umbilical teflon silvered three inch wires (nine 24gage). this enables ease swapping out communist china genuine phillips tda1514a modules, no grease just TO3 thermal grey pad, and star lock washer compression fasteners. but does the added three inches react adversely as crosstalk aerial antennae? realize phillips intentionally distanced small signals from heavy signals insofar as SIP terminals.
17 your responses are welcome (amp sings sassy brit, esp chnnl2 snazzy rounded clipping jfet intrinsic behavior but is it right iaw elliot's designed intentions?)
A schematic would help. The only Tramp schematic I have is dated 1996 and uses an FET output stage.
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schematic tramp non super
Schematic located in thread super tramp biasing preamp fet's
And last night playing, 650mA fastblow opened, occurred because powerup switch exercised repeatedly every five seconds, about five full cycles.
The powerup dc momentary into spkr results when dials all minimum.
But if dials are preset for actual output, the dc goes away.
You need the scope to see this since its so brief.
Gotta chk why fuse opened, maybe filament fatigue, original old aged, maybe should get sloblow replc.
Schematic located in thread super tramp biasing preamp fet's
And last night playing, 650mA fastblow opened, occurred because powerup switch exercised repeatedly every five seconds, about five full cycles.
The powerup dc momentary into spkr results when dials all minimum.
But if dials are preset for actual output, the dc goes away.
You need the scope to see this since its so brief.
Gotta chk why fuse opened, maybe filament fatigue, original old aged, maybe should get sloblow replc.
schematic tda1514a tramp poweramp
Rats android unable to upload its schematic, gotta resort to laptop, pl stndby
Provided schematic, caution editorial errors original factory based on actual factory circuit orig,
Rats android unable to upload its schematic, gotta resort to laptop, pl stndby
laptop schematic uploaded
there's a penguin replacement poweramp, what does that mean? was the tda1514a designed folly?
what kinds of folly(s)?
still retained original factory tda1514a (phillips) but comparison fluke measurements with communist china's tda1514a (phillips) does reveal indifferences (pin eight earthed to heatsink backplane die of china but not of factory orig tda1514a.
question is whether orig has been injured (wounded) along its life, or whether intrinsic circuitry within china tda1514a has been amended with improvements modifications, or, whether the china tda1514a is not up to snuff period.
maybe should detach (decouple) preamp from poweramp and individually checkout both tda1514a's impose upon spkr dc using poweramp alone energized.
or, it may be there's injured discrete components on board the poweramp pcb (powersupply poweramp integrated pcb). i dont suspect the metalized film caps (plastic rectanguloid chicklets) are culprits, but should check each one out of circuit. metalized film caps pinhole burnthrough (self healing) and never short but cap value will decrease, how much, guess it progressively worsens (snowball effect).
the poweramp ps pcb has just two micromolex connections, input ps secondary (ct, so three pins), and preamp pcb interface (+35dc, -35dc, CT[0volt], preamp signal receipt).
and there's just one 18gage utility company earth wire hardsoldered into the preamp pcb (chassis earth).
there's proportional dc to the spkr during hard loud playing (guitar signal), dials all at lunch hour, fluke snags peak dc, never exceeds 1 whole volt, but there shouldnt be any appreciable dc. the ac is much larger ranging 2 to 4 volts dependent upon preamp dials permissivity of energy flow into poweramp. so it looks like the poweramp ac zero datum rides upon a dc datum that fluctuates somewhat mildly relative to energy level delivered into spkr ( i observed fluke minus polarity dc).
there's a penguin replacement poweramp, what does that mean? was the tda1514a designed folly?
what kinds of folly(s)?
still retained original factory tda1514a (phillips) but comparison fluke measurements with communist china's tda1514a (phillips) does reveal indifferences (pin eight earthed to heatsink backplane die of china but not of factory orig tda1514a.
question is whether orig has been injured (wounded) along its life, or whether intrinsic circuitry within china tda1514a has been amended with improvements modifications, or, whether the china tda1514a is not up to snuff period.
maybe should detach (decouple) preamp from poweramp and individually checkout both tda1514a's impose upon spkr dc using poweramp alone energized.
or, it may be there's injured discrete components on board the poweramp pcb (powersupply poweramp integrated pcb). i dont suspect the metalized film caps (plastic rectanguloid chicklets) are culprits, but should check each one out of circuit. metalized film caps pinhole burnthrough (self healing) and never short but cap value will decrease, how much, guess it progressively worsens (snowball effect).
the poweramp ps pcb has just two micromolex connections, input ps secondary (ct, so three pins), and preamp pcb interface (+35dc, -35dc, CT[0volt], preamp signal receipt).
and there's just one 18gage utility company earth wire hardsoldered into the preamp pcb (chassis earth).
there's proportional dc to the spkr during hard loud playing (guitar signal), dials all at lunch hour, fluke snags peak dc, never exceeds 1 whole volt, but there shouldnt be any appreciable dc. the ac is much larger ranging 2 to 4 volts dependent upon preamp dials permissivity of energy flow into poweramp. so it looks like the poweramp ac zero datum rides upon a dc datum that fluctuates somewhat mildly relative to energy level delivered into spkr ( i observed fluke minus polarity dc).
tramp operating but weird anomaly to discuss
Got tramp up and running, the butchered traces and landings, aluminum electrolytics, j112's, bussing mini connectors, gain2pot, reverb tank rca connectors corrosion, tda1514a, cliff jack switch contact tensions, all done successfully.
Anomaly exists. Telecaster tone knob variation jumps amp into another signature realm, don't understand why. Happens when headed for full treble cut of tele quarterwatt tone pot, A1M alpha, 682 orangedrop. Tele has quarterwatt alpha A1M vol pot hipass cap 102
I did vacant channel two's preamp rail anti oscillation caps, three of them, 472, 472, 471
Also sensitized both channels slope resistors, 47k to 100k, 33k to 68k
also favored hi's channel one eliminating neg feedback cap first stage 221 changed to 10pf
And gain1 pot hipass cap changed from 201 to 221, schematic says orig value should be 181
Also added tant104 cap cathode bypass stage1 chnnl1
Augmented chnnl2 stage1 cathode bypass with additional tant474
Augmented existent cathode bypass cap chnnl2 stage5 with tant475
Also augmented recovery reverb cathode bypass tant475
Pinched hifreq presence pot by reducing the cap from 102 to 221
Hipassed both chnnl gain pots using 221 ceramic caps
Also replaced shielded umbilical used to detour chnnl2 stages via switch1 schematic, new wire is zero capacitance coaxial.
Replaced bridge rectifiers with 100 volt schotty 3amperes
Umbilicaled header for tda1514a quick disconnect easing swapout
Any suggestions to resolve tone pot of tele anomaly?
Resonance?
Wondering if power transport and delivery is somehow causing starvation since tele hicut essentially demands more electricity to process bass music material, right?
There's a lineside 620ma fuse (fastblow that I changed to slowblow). Rated spkr output must be twentyfive watts tda1514a poweramp.
Got tramp up and running, the butchered traces and landings, aluminum electrolytics, j112's, bussing mini connectors, gain2pot, reverb tank rca connectors corrosion, tda1514a, cliff jack switch contact tensions, all done successfully.
Anomaly exists. Telecaster tone knob variation jumps amp into another signature realm, don't understand why. Happens when headed for full treble cut of tele quarterwatt tone pot, A1M alpha, 682 orangedrop. Tele has quarterwatt alpha A1M vol pot hipass cap 102
I did vacant channel two's preamp rail anti oscillation caps, three of them, 472, 472, 471
Also sensitized both channels slope resistors, 47k to 100k, 33k to 68k
also favored hi's channel one eliminating neg feedback cap first stage 221 changed to 10pf
And gain1 pot hipass cap changed from 201 to 221, schematic says orig value should be 181
Also added tant104 cap cathode bypass stage1 chnnl1
Augmented chnnl2 stage1 cathode bypass with additional tant474
Augmented existent cathode bypass cap chnnl2 stage5 with tant475
Also augmented recovery reverb cathode bypass tant475
Pinched hifreq presence pot by reducing the cap from 102 to 221
Hipassed both chnnl gain pots using 221 ceramic caps
Also replaced shielded umbilical used to detour chnnl2 stages via switch1 schematic, new wire is zero capacitance coaxial.
Replaced bridge rectifiers with 100 volt schotty 3amperes
Umbilicaled header for tda1514a quick disconnect easing swapout
Any suggestions to resolve tone pot of tele anomaly?
Resonance?
Wondering if power transport and delivery is somehow causing starvation since tele hicut essentially demands more electricity to process bass music material, right?
There's a lineside 620ma fuse (fastblow that I changed to slowblow). Rated spkr output must be twentyfive watts tda1514a poweramp.
help, schematic
here it is, help, telecaster tone knob zero'd tramp just zooms jumps high end dirty channel.
here it is, help, telecaster tone knob zero'd tramp just zooms jumps high end dirty channel.
Since an issue with replacing a TDA1514A chip is now apparently resolved (https://dandini.wordpress.com/2010/10/22/marshall-guitar-amp-tda1514a-repair-issues/), the OP has moved on to more questions, this time about tone control interaction.
Actually, it's all about Instruments and Amps and should be moved or posted there, where the guitar speak may be more easily understood: Instruments and Amps - diyAudio
Actually, it's all about Instruments and Amps and should be moved or posted there, where the guitar speak may be more easily understood: Instruments and Amps - diyAudio
lost track problems
Dc applied spkr on cold pwrup, telecaster jumps loud onboard tone zero'd, dc rail cross connect 47uf 63wvdc inadequate rating, mimmick same local select switch for reverb switch as done for chnnl/boost switch localized?
Dc applied spkr on cold pwrup, telecaster jumps loud onboard tone zero'd, dc rail cross connect 47uf 63wvdc inadequate rating, mimmick same local select switch for reverb switch as done for chnnl/boost switch localized?
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