every un/tightening step is putting pcb under the strain
you really need some special made screw terminals for soldering on pcb, for instance those looking as bridge , having two knife form ends to solder on pcb
and even then, you need to look for cracks, and resolder, to release strain put on solder mass
all that is good and proper practice in, say, industrial equipment, but just take a look at any of modules as that, and see how they're made
in-out, in-out, in-out, in-out, in-out......... why would I do that?
you really need some special made screw terminals for soldering on pcb, for instance those looking as bridge , having two knife form ends to solder on pcb
and even then, you need to look for cracks, and resolder, to release strain put on solder mass
all that is good and proper practice in, say, industrial equipment, but just take a look at any of modules as that, and see how they're made
in-out, in-out, in-out, in-out, in-out......... why would I do that?
I don't know about you, but I like to refill the magic smoke from time to time.
Hybrid solution of MoFo with TPA3255 (class D)
Two loudspeakers are currently in the planning stage:
- 4-way open baffle as a replica of the LX521 by Linkwitz.
- 2-way tweeter horn with bass in BR cabinet or CB activ equalised.
The music signal comes via audio PC and 8-channel audio interface. The speakers are actively separated via Acourate software.
Both speakers will be placed in the same room and driven by the same amplifiers.
The 18sound compression driver in the tweeter horn delivers 110dB and here I see the MoFo with its low noise as the solution. Best sound is added. The tweeters of the LX521 should also get their signal from the MoFo.
I want to supply the tweeter with the MoFo, which, if I understand this correctly, passes on the volume from the preamplifier 1:1.
I would like to solve all other frequency ranges via TPA3255 (class D) which amplifies the signal with a certain gain factor.
I will save different setups (crossover frequency, time delay and level) separately for both speakers in the Acourate setup.
Is it possible to synchronise this combination of MoFo and TPA3255 so that the volume change is synchronised for both types of amplifier?
Two loudspeakers are currently in the planning stage:
- 4-way open baffle as a replica of the LX521 by Linkwitz.
- 2-way tweeter horn with bass in BR cabinet or CB activ equalised.
The music signal comes via audio PC and 8-channel audio interface. The speakers are actively separated via Acourate software.
Both speakers will be placed in the same room and driven by the same amplifiers.
The 18sound compression driver in the tweeter horn delivers 110dB and here I see the MoFo with its low noise as the solution. Best sound is added. The tweeters of the LX521 should also get their signal from the MoFo.
I want to supply the tweeter with the MoFo, which, if I understand this correctly, passes on the volume from the preamplifier 1:1.
I would like to solve all other frequency ranges via TPA3255 (class D) which amplifies the signal with a certain gain factor.
I will save different setups (crossover frequency, time delay and level) separately for both speakers in the Acourate setup.
Is it possible to synchronise this combination of MoFo and TPA3255 so that the volume change is synchronised for both types of amplifier?
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Nice price if anyone is looking for a pair of 195T5's
HAMMOND 195T5 REACTOR; DC; CHOKE; 100MH; 5A; .64OHMS | eBay
HAMMOND 195T5 REACTOR; DC; CHOKE; 100MH; 5A; .64OHMS | eBay
If you use less bias current and MOSFET size, for headphone leves, is good to increase inductance proportional to your load, for reference.
But if you maitain high current operation (original sized MoFo), I don't see any problems.
Use of less current is good to build a smaller compact model for headphones.
Inductor will be smaller also (will need support less DC bias current)
For those of us not needing every last watt this design is capable of might not the voltage gain stage from the new Sony Vfet amp be a nice option. DIY Sony VFET pt 1
Good choice for Class D amp. The standard issue TPA3255 has 22dB gain. The ones with PFFB have 16dB gain. The MoFo has 0dB gain. You will need some sort of preamp for MoFo with similar gain as the TPA3255. If using a DSP as XO to control all of this, changing a master volume will affect all in unison. However, a DSP will not be able to drive the MoFo to levels high enough to match your mids and woofers.
Assuming you want to be able to hit the typical 11w max power from a MoFo into 8ohms, you need sqrt(11v x 8ohms)=9.4vrms or 24Vpp. Any opamp based preamp with +/-15v rails and circa 22dB gain should be able to do this. Use that in between the DSP output and the MoFo.
The TPA3255 can also use a preamp as most sources have a hard time reaching clip with a 22dB gain. Also, the TPA3255 likes to see balanced input. So ideally you want a 6dB gain balanced output preamp to reach typical 28dB needed for most sources to hit max. In that case, the preamp for MoFo should be 28dB or so. Within the DSP you can make +/-6dB adjustments to dial in the relative balance of the woofer/mid/tweeter.
It goes without saying that to do this right you need a calibrated microphone and software like REW.
After the good result obtain with EF180 instead of 6072A in Power Follower I am using now a new driver for the Inpol / Mofo using the 6Z51P.
The 6Z51P is near to the D3a and it is tested on the article of Bartola about russian pentode.
I will update you on result.
The 6Z51P is near to the D3a and it is tested on the article of Bartola about russian pentode.
I will update you on result.
Attachments
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The sound is very good with the 6Z51P but remember to change the pins on socket because are different from D3a and EF180
I have use 290V, 4x39K 2W on anode and 100ohm on cathode with 470uF
I can share pcb files and the complete components list
Here the pcb, some little modifications are necessary to use the 6Z51P instead of D3a / E180F
Attachments
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Current amplifier stage
R1,R2,R4,R5 1800ohm 1/4W 1%
R3 10Kohm 2W
R6,R7 220K 1/4W 1%
R9,R11 0.22ohm 5W Mills RMA5
C1 4700uF 16V Nichicon model UKA1C472MHD
U$1 0.68uF 400V Clarity Cap CMR or other audio grade MKP
R8 10Kohm multi turn
Q1,Q2 IRFP240PBF (it would be desirable to make a selection based on current)
D1,D2 zener 15V 1W
D3 zener 10V 1W
F1 fuse 10A FAST with fuse holder Mouser 534-4628
Cout min. 10000uF 50V Nichicon KG Mouser
Isolators Bergquist SP400-0.007-00-104 RS RS541-0856
Voltage amplifier
R1,R2,R18,R19 22Kohm 1/2W 1%
R3,R4,R20,R21 2200ohm 1/4W 1%
R5,R6,R8,R9,
R10,R26,R22,R23 39Kohm 2W
R7,R24 100ohm 1/4W 1% https://www.mouser.it/ProductDetail/71-RN60D1000F-R
R37,R39 47ohm 1/4W 1%
R11,R34 4700ohm 1/4W 1%
R12,R30 2 x 100Kohm 1/4W 1% to have 200K
R13,R28 4700ohm 1/4W 1%
R14,R29 150Kohm 3W
R17,R33 3.3ohm 2W
R25,R35 0ohm
R15,R16,R31,R32 220ohm 1/4W 1%
C1.C3 220uF 6.3V
C2,C4 33uF 400V https://www.mouser.it/ProductDetail/647-UVY2G330MHD
C5,C6 100uF 400V https://www.mouser.it/ProductDetail/647-LGU2G101MELZ
CY1-CY8 10nF 440VAC https://www.mouser.it/ProductDetail/80-R474I210050A1K
D1,D2,D3,D4,D6,D7,D8,D9 UF5406 https://www.mouser.it/ProductDetail/625-UF5408-E3
D5,D10 zener 10V 1W https://www.mouser.it/ProductDetail/78-1N4740A-TAP
U$3,U$6 IRF840
U$11,U$7 33uF 400V Solen MKP
KK1,KK4 Extruded Style Heatsink for TO-220 Mouser: 532-513102B25
Isolator Bergquist SP400-0.007-00-54 RS 169-2177
Isolatos TO-220 nylon platstic Insulator hole size M3
or see on my web page
Hi All,
As there's another similar project based on Mr. MR's MoFo:
LuFo Amp - 39w SE Class A from 28v Rail
I thought that I could ask a local transformer buider FIAT (link) to make a price for 30 pairs or more inductors with mounting frame having those features:
70mH, 5Adc and max 0,7 Ohm Rdc
It would cost 50€/pair (25€ each inductor) + shipping.
We can start a GB if interested
As there's another similar project based on Mr. MR's MoFo:
LuFo Amp - 39w SE Class A from 28v Rail
I thought that I could ask a local transformer buider FIAT (link) to make a price for 30 pairs or more inductors with mounting frame having those features:
70mH, 5Adc and max 0,7 Ohm Rdc
It would cost 50€/pair (25€ each inductor) + shipping.
We can start a GB if interested
Is there a simulated data about Zout because cascode will increse this value.Hi All,
As there's another similar project based on Mr. MR's MoFo:
LuFo Amp - 39w SE Class A from 28v Rail
I thought that I could ask a local transformer buider FIAT (link) to make a price for 30 pairs or more inductors with mounting frame having those features:
70mH, 5Adc and max 0,7 Ohm Rdc
It would cost 50€/pair (25€ each inductor) + shipping.
We can start a GB if interested