Dear members,
First post but have enjoy reading since started doing own modding and learning(I hope!)
Coming from engineering background I make every attempt to keep it safe and stay within ability and after finding able to fix a few simple problem with spares/ repairs amps etc, caught the bug(as it were?!)
Confident with soldering now and interest is in marantz equipment and becoming more familiar with components and upgrading them with amazing results.
Would really appreciate some pictorial assistance with connecting a tube output ( kit form) with left and right channels, safely into the Philips tda 1541a?
I've seen one method but it's only ONE wire from the link wire directly below it and capacitor just below that to the right disconnected at upper end. I was thinking you would need left/right channel from tda to l/r channels to tube input?
im going for a smaller lower voltage kit and upgrading components where necessary. I already have a 12v version but have seen dual 18v version I believe dual rail regs and heatsinks which appears better in theory?
Further mods interested in and able to do ok myself are:
1/ improved op amps(burr brown?)
2/NOS mode
3/New capacitors inc audiograde film/oil at 1uf and below where appropriate.
4/Remove transformer of PCB and wire in separate toroidals for 5v and 15v plus power for tubes via toroidal. I may use soft start and individual fuse them.
5/upgrade regulators/heat shields because this made a big difference to my pm-32 project( expensive but worth it, I thought)
6/ shielded and twisted cabling neatly positioned( with earth drain where needed.
7/ mains filter
Damp the casing and was considering adding weight to the bottom exterior as well.
8/Better RCA, silver wiring made up by myself
9/damping the crystal(new?)
or possibly trichord upgrade?
10/ modding the puck as follows:
floating roller bearing system on a arm
c/s screw through puck into above allowing adjustment to tension/height
adding thick silicon oil to cavity in puck and seal off with washer in an attempt to act as a harmonic balancer and hope to aid in vibration? Worth a try.
ive also found on cdm-4 that if thin rubber on spindle is worn then it can cause disc to slip and come up with read error?
Not compitant enough to build separate supplies have had success in multiple toroidal build on separate case which switched on with main cd unit. Used aircraft style metal connectors. Having longer AC voltage cables and DC voltage PSU left in close proximity on PCB as factory but with better components still made quite a difference.
Many thanks, Phil
First post but have enjoy reading since started doing own modding and learning(I hope!)
Coming from engineering background I make every attempt to keep it safe and stay within ability and after finding able to fix a few simple problem with spares/ repairs amps etc, caught the bug(as it were?!)
Confident with soldering now and interest is in marantz equipment and becoming more familiar with components and upgrading them with amazing results.
Would really appreciate some pictorial assistance with connecting a tube output ( kit form) with left and right channels, safely into the Philips tda 1541a?
I've seen one method but it's only ONE wire from the link wire directly below it and capacitor just below that to the right disconnected at upper end. I was thinking you would need left/right channel from tda to l/r channels to tube input?
im going for a smaller lower voltage kit and upgrading components where necessary. I already have a 12v version but have seen dual 18v version I believe dual rail regs and heatsinks which appears better in theory?
Further mods interested in and able to do ok myself are:
1/ improved op amps(burr brown?)
2/NOS mode
3/New capacitors inc audiograde film/oil at 1uf and below where appropriate.
4/Remove transformer of PCB and wire in separate toroidals for 5v and 15v plus power for tubes via toroidal. I may use soft start and individual fuse them.
5/upgrade regulators/heat shields because this made a big difference to my pm-32 project( expensive but worth it, I thought)
6/ shielded and twisted cabling neatly positioned( with earth drain where needed.
7/ mains filter
Damp the casing and was considering adding weight to the bottom exterior as well.
8/Better RCA, silver wiring made up by myself
9/damping the crystal(new?)
or possibly trichord upgrade?
10/ modding the puck as follows:
floating roller bearing system on a arm
c/s screw through puck into above allowing adjustment to tension/height
adding thick silicon oil to cavity in puck and seal off with washer in an attempt to act as a harmonic balancer and hope to aid in vibration? Worth a try.
ive also found on cdm-4 that if thin rubber on spindle is worn then it can cause disc to slip and come up with read error?
Not compitant enough to build separate supplies have had success in multiple toroidal build on separate case which switched on with main cd unit. Used aircraft style metal connectors. Having longer AC voltage cables and DC voltage PSU left in close proximity on PCB as factory but with better components still made quite a difference.
Many thanks, Phil
Welcome to diyAudio 🙂
The TDA1541 is dual channel DAC and its basic audio output as configured in the player is in the form of a current output rather than a voltage. The opamps in the player convert that into a normal voltage output.
We would need to know a lot more about what you are trying to do 🙂 If by
you mean a valve preamp of some sort then that would have to take its signal from after the opamps.
This is how your DAC is configured (absolutely standard practice) and it means there is no measurable signal voltage at the DAC output.
https://www.by-rutgers.nl/IV-converter.html
This is the CD40. Pin 6 and 25 are the audio outputs but there is no actual usable voltage here. Pin 1 of the two right hand opamps are where the actual audio makes an appearance in voltage form.
The TDA1541 is dual channel DAC and its basic audio output as configured in the player is in the form of a current output rather than a voltage. The opamps in the player convert that into a normal voltage output.
We would need to know a lot more about what you are trying to do 🙂 If by
you mean a valve preamp of some sort then that would have to take its signal from after the opamps.
This is how your DAC is configured (absolutely standard practice) and it means there is no measurable signal voltage at the DAC output.
https://www.by-rutgers.nl/IV-converter.html
This is the CD40. Pin 6 and 25 are the audio outputs but there is no actual usable voltage here. Pin 1 of the two right hand opamps are where the actual audio makes an appearance in voltage form.
Thanks for the welcome, mooly😀🤔
Appreciate the diagram and info as it's a very good learning aid too.
The cd-40 is on its way looks to be a good one owner player( I hope)so can study then but yes the end result is to achieve a tube o/p but keeping it fairly straight forward as a first attempt.
Not going to upgrade any other components unless essential until tube mod is fully working safely. Notice cd-40 has good access too.
So the op amps being left and right channel would require a connection from each pin 1 to respective inputs to valve pre-amp and then earthed back to PCB?
the tube pre amp PCB is based on music fidelity( the cheap one ) to try it has volume control pot so possible to adjust output. Like mentioned there is a dual 18v version as well which may better bet. The components are not the best but do come with tubes and can experiment with upgraded film caps etc as know these made quite a difference to another project. It will be powered by a toroidal taken after the switch and fuse taken off PCB 240v input with its own fuse. This actually would be a good time to remove old transformer and also mount a toroidal(s) remotely In the empty spaces and running AC voltage shielded leads back to outputs on PCB.
Is my understanding correct?
Cheers, Phil
Appreciate the diagram and info as it's a very good learning aid too.
The cd-40 is on its way looks to be a good one owner player( I hope)so can study then but yes the end result is to achieve a tube o/p but keeping it fairly straight forward as a first attempt.
Not going to upgrade any other components unless essential until tube mod is fully working safely. Notice cd-40 has good access too.
So the op amps being left and right channel would require a connection from each pin 1 to respective inputs to valve pre-amp and then earthed back to PCB?
the tube pre amp PCB is based on music fidelity( the cheap one ) to try it has volume control pot so possible to adjust output. Like mentioned there is a dual 18v version as well which may better bet. The components are not the best but do come with tubes and can experiment with upgraded film caps etc as know these made quite a difference to another project. It will be powered by a toroidal taken after the switch and fuse taken off PCB 240v input with its own fuse. This actually would be a good time to remove old transformer and also mount a toroidal(s) remotely In the empty spaces and running AC voltage shielded leads back to outputs on PCB.
Is my understanding correct?
Cheers, Phil
Pin 1 is the first place the fully processed audio appears, however...
The non polarised capacitor on pin 1 blocks any DC that may be present. There may be a small DC voltage on pin 1 although ideally it should be close to zero. The two 100 ohm resistors and the two transistors are for the audio muting. When the transistors are on the audio is shunted to ground. This is actually quite an important part of the design and is under control of the System Control uP (Microprocessor) and essentially prevents you from hearing things you shouldn't such as pops and clicks and thumps when for example you jump tracks or power the unit on and off.
So by the time you are at the right hand end of that diagram where it says LEFT RIGHT you are at the point that connects to the output sockets.
So a low voltage tube design if it runs on -/+18 volts. Is that what you mean? Fusing any transformer is always recommended on safety grounds.
I'm not following the bit on removing the old transformer... in what ? 🙂
Thanks again, I can see now with explanation and diagram.
Its starting to make sense now!
Ref the low voltage kit- it states it requires dual 18v AC input. It's on eBay etc from China cheapest is £22 or so delivered. It had word 'bile' in title(?) Described as having sweet sound and more stable than the single 12v version and cheaper( I have one to try the PCB is very good quality) .
I can't see on picture of PCB exactly what type of regs as they don't state in description but they have a very large common heat sink, would take a stab at being 15v +/- regs as guess quite hot with 18v and probably more from a toroidal. Not 100 percent sure but just educated guess. It use 6j tubes X2.
It may well fit inside the cd-40 as a complete assembly with small footprint.
Ref the transformer- removing the old transformer from the PCB immediately behind the cdm-4 in the cd-40 as it will be affecting the whole board and cdm-4 with vibrations etc.
Mounting toroidal well away off the PCB and shield and provide isolation. Affective there will be a large gap left behind cdm-4 for something else like a mains filter possibly fuses etc. I'm hoping to fit 3(?) small toroidals potentially in the spaces to the right in the cd-40.
All being fed via fuses from the 240v input from PCB and going to the tube onboard PSU and back to the PCB at the point they go on there merry way to supply the onboard psu for the various aspects of cd player as mentioned( without looking I believe 5 and 15v but will confirm)
As a footnote I completed a dedicated transformer box( old marantz tuner( cheaper than new project boxes!) With soft start mains filter multi fuse distribution board and a DC 3v rectifier for indication lights and connected it to an audio alchemy transport( without its vibrating transformer!) And the results amazed me. Very surprised how much difference it made to the sound quality. I also added larger heat sinks to regs as were running very hot before ( too hot- unable to touch for long!) I did the mods.
Would be interested to here other members experience?
Thanks mooly 😀
Its starting to make sense now!
Ref the low voltage kit- it states it requires dual 18v AC input. It's on eBay etc from China cheapest is £22 or so delivered. It had word 'bile' in title(?) Described as having sweet sound and more stable than the single 12v version and cheaper( I have one to try the PCB is very good quality) .
I can't see on picture of PCB exactly what type of regs as they don't state in description but they have a very large common heat sink, would take a stab at being 15v +/- regs as guess quite hot with 18v and probably more from a toroidal. Not 100 percent sure but just educated guess. It use 6j tubes X2.
It may well fit inside the cd-40 as a complete assembly with small footprint.
Ref the transformer- removing the old transformer from the PCB immediately behind the cdm-4 in the cd-40 as it will be affecting the whole board and cdm-4 with vibrations etc.
Mounting toroidal well away off the PCB and shield and provide isolation. Affective there will be a large gap left behind cdm-4 for something else like a mains filter possibly fuses etc. I'm hoping to fit 3(?) small toroidals potentially in the spaces to the right in the cd-40.
All being fed via fuses from the 240v input from PCB and going to the tube onboard PSU and back to the PCB at the point they go on there merry way to supply the onboard psu for the various aspects of cd player as mentioned( without looking I believe 5 and 15v but will confirm)
As a footnote I completed a dedicated transformer box( old marantz tuner( cheaper than new project boxes!) With soft start mains filter multi fuse distribution board and a DC 3v rectifier for indication lights and connected it to an audio alchemy transport( without its vibrating transformer!) And the results amazed me. Very surprised how much difference it made to the sound quality. I also added larger heat sinks to regs as were running very hot before ( too hot- unable to touch for long!) I did the mods.
Would be interested to here other members experience?
Thanks mooly 😀
Without seeing actual circuit diagrams it is hard to say. 18 volt AC when rectified and smoothed will give around 25 volts DC. So dual 18 vac can be configured to give -/+25 volts.
The power supply in the Marantz uses many interconnected rails and also rails that 'float' such as for the display. The transformer has multiple windings.
Rail sequencing can be important in digital circuits (like the Marantz) where the rise time of the rails is important. If some appear before others then various weird faults can appear such as lockups and so on.
The power supply in the Marantz uses many interconnected rails and also rails that 'float' such as for the display. The transformer has multiple windings.
Rail sequencing can be important in digital circuits (like the Marantz) where the rise time of the rails is important. If some appear before others then various weird faults can appear such as lockups and so on.
I think you entered a cave with a pair of binoculars.
Start with the basics of understanding how this cd player works (which is a good base for having fun) go to the old site of Mathias Fikus alias the Lampisator, you will find everything you want on the NOS mod of the tda1541 , the I/V stage, the buffer and various tube output stage diagrams.
But really, above all, try to understand how the machine works in its original state and then start the mods one by one and listen.
Start with the basics of understanding how this cd player works (which is a good base for having fun) go to the old site of Mathias Fikus alias the Lampisator, you will find everything you want on the NOS mod of the tda1541 , the I/V stage, the buffer and various tube output stage diagrams.
But really, above all, try to understand how the machine works in its original state and then start the mods one by one and listen.
Thanks mooly and huggygood for advice. It's a steep learning curve and I think I've also got those binoculars the wrong way round and the covers on...
I'll be mindful of the transformer and relation to providing power to the voltage rails. I've spent time taking readings on a great number
PCB of various components to see the affects and what you are saying are answers to questions I've had in the back of mind, so cheers.
The dual rail tube kit has been offered at a discount(£17) so I'm ordering and would like to
post the pictures when it arrives.
It will provide build experience and I can test it and learn from it. Then look at adding it once I've gained more knowledge as you quite rightly say.
I greatly appreciate the help!🙂
I'll be mindful of the transformer and relation to providing power to the voltage rails. I've spent time taking readings on a great number
PCB of various components to see the affects and what you are saying are answers to questions I've had in the back of mind, so cheers.
The dual rail tube kit has been offered at a discount(£17) so I'm ordering and would like to
post the pictures when it arrives.
It will provide build experience and I can test it and learn from it. Then look at adding it once I've gained more knowledge as you quite rightly say.
I greatly appreciate the help!🙂
Mooly, just taking on board your advice about how the rails operate in the marantz and transformer.
I can see the original is multi winding. So apart from space saving a multi winding transformer of any type could operate 'quicker' and in 'time' plus be more sensitive in this case? Once I have readings from original I can experiment because I have quite a few toroidals Inc a multi winding that could be suitable but not until installed tubes ONE mod at a time!
One thought is that the a multi winding toroidal just above where the original was but mounted off the PCB with equal length short leads could be the answer if get issues
I can see the original is multi winding. So apart from space saving a multi winding transformer of any type could operate 'quicker' and in 'time' plus be more sensitive in this case? Once I have readings from original I can experiment because I have quite a few toroidals Inc a multi winding that could be suitable but not until installed tubes ONE mod at a time!
One thought is that the a multi winding toroidal just above where the original was but mounted off the PCB with equal length short leads could be the answer if get issues
I doubt you would find a multi winding transformer as an off the shelf part having all the correct voltages. It would have to be a custom wound product. Don't underestimate how difficult swapping the transformer might be.
It looks the voltages are in the region of 30-17-7.5-0-7.5-17-30 for one winding and then there is a separate isolated one for the display filaments. You would have to measure that but typically they are around 3 volts AC in total and so that would be a 1.5-0-1.5 but you would definitely have to measure that first.
It looks the voltages are in the region of 30-17-7.5-0-7.5-17-30 for one winding and then there is a separate isolated one for the display filaments. You would have to measure that but typically they are around 3 volts AC in total and so that would be a 1.5-0-1.5 but you would definitely have to measure that first.
Thanks mooly
I won't take it lightly. Looking at the diagram is helpful along with explanation. I've learnt about importance of voltages and yes there is some tolerance and I've also got a temp. Probe on my meter to compare more accurately in theory. Every volt over the rated voltage of a regulator is 1watt lost in heat if understand correctly.
It's possible I may have one as keep an eye out for used ones from projects but it will only be luck. Otherwise I will get one rewound specially when get to that stage.
I've ordered the tube kit £20 all in from china. It looks to be a good starting point I hope. I know the pcb's are decent quality and it's in English as well! Tubes included. I'm looking forward to getting it operational.
I won't take it lightly. Looking at the diagram is helpful along with explanation. I've learnt about importance of voltages and yes there is some tolerance and I've also got a temp. Probe on my meter to compare more accurately in theory. Every volt over the rated voltage of a regulator is 1watt lost in heat if understand correctly.
It's possible I may have one as keep an eye out for used ones from projects but it will only be luck. Otherwise I will get one rewound specially when get to that stage.
I've ordered the tube kit £20 all in from china. It looks to be a good starting point I hope. I know the pcb's are decent quality and it's in English as well! Tubes included. I'm looking forward to getting it operational.
The voltage across the regulator multiplied by the current through the regulator will give you the power dissipation in the regulator. So a 15 volt regulator supplying 0.45 amps and fed with 19 volts input dissipates 1.8 watts. Increase the input to 20 volts and it dissipates 2.25 watt. Another volta and it is 2.7 watt.
It is a complex subject fraught with difficulty. You need to know the average current draws from each winding because that determines the gauge of wire to be used and the 'VA' rating to be designed for.
Although the average voltage input to a reg might be say 20 volts (for a 15 volt reg) you have to account for the ripple on the unregulated input side. If that dips below the regulators 'drop out voltage' then the output is suddenly not clean and stable any more and will contain a high ripple content. You also have to account for worst case mains voltage variations above and below your nominal supply supply.
Good luck with the kit 🙂
It is a complex subject fraught with difficulty. You need to know the average current draws from each winding because that determines the gauge of wire to be used and the 'VA' rating to be designed for.
Although the average voltage input to a reg might be say 20 volts (for a 15 volt reg) you have to account for the ripple on the unregulated input side. If that dips below the regulators 'drop out voltage' then the output is suddenly not clean and stable any more and will contain a high ripple content. You also have to account for worst case mains voltage variations above and below your nominal supply supply.
Good luck with the kit 🙂
Appreciate it, mooly.
I've heard it's complex, sometimes you have to go on what feels ok to touch or probe better still and smell! Yes I've come across some of things you mentioned and thanks for clarification from an expert. It's like 230v primary I notice with 246v mains increased the secondary no load voltage up above the claimed amount especially on toroidals. Also the ripple current I was 💯 about I sought of had some grasp about not having to lower a voltage as this can cause more problems something like it throws the diode out or something along those lines!
The pm-32 project(first) has a slightly lower voltage toroidal, close VA, Danish super regs with heat sinks and it runs luke warm. There's were £40 each and wanted to protect them. It has more gain and very clean sound. With all the other joint upgrading inc. copper on chassis it has very refined sound and deep soundstage etc. A lot of marantz from similar periods run very hot regs especially the negative I think and no heat sink. You get tell tale discoloration on back of PCB and dry joints or failure. I reflow the whole board now to make sure.
Thanks again I will post you when underway with project🙂
I've heard it's complex, sometimes you have to go on what feels ok to touch or probe better still and smell! Yes I've come across some of things you mentioned and thanks for clarification from an expert. It's like 230v primary I notice with 246v mains increased the secondary no load voltage up above the claimed amount especially on toroidals. Also the ripple current I was 💯 about I sought of had some grasp about not having to lower a voltage as this can cause more problems something like it throws the diode out or something along those lines!
The pm-32 project(first) has a slightly lower voltage toroidal, close VA, Danish super regs with heat sinks and it runs luke warm. There's were £40 each and wanted to protect them. It has more gain and very clean sound. With all the other joint upgrading inc. copper on chassis it has very refined sound and deep soundstage etc. A lot of marantz from similar periods run very hot regs especially the negative I think and no heat sink. You get tell tale discoloration on back of PCB and dry joints or failure. I reflow the whole board now to make sure.
Thanks again I will post you when underway with project🙂
That effect is caused by something called the regulation factor of the transformer. The smaller a transformer and the more pronounced the effect. The figure is often given in the data sheets as a percentage showing no load voltage vs full load voltage. For a big toroid it can be as low as 3% and for a small one as high as 16% or more.
That's a problem on lots of commercial gear. Discolouration is caused by chemical changes in the board and the older (paxolin type is worse than fibreglass for this.
I noticed that- all toroidals read higher no load 9v being 11.3v etc except one and that was a quality NOS British item fitted to the 32. It measured exactly 24.2-0-24.2 almost as specified. The mains has gone up to 252v in one case compounding the matter for the 9v tran to 11.7.
The 24v had a 240v single primary. I guess this is why more accurate unless it was lower than specified say 23+v not sure? I purchased another as £9 each and even had the correct connector to plug straight in almost like it was made for it!
I've seen a Cambridge audio toroidal on eBay £25 with 2 outputs that may be useful but could be a waist of money. There is an audio grade on eBay for £48 but can offer rch engineering very helpful chap. Its 17-0-17 X2 and 7-0-7 approx.
Just wondering if I could use? I know the 30-0-30 is needed and 3v (to be measured) as separate transformers but the extra 17-0-17 approx (slightly higher) could supply the tube PSU?
Is this too risky? Adding the other transformer costs would still make it a good buy?
Is there anyone you can recommend a custom rewind that you use? Do you know rough costs?
The 24v had a 240v single primary. I guess this is why more accurate unless it was lower than specified say 23+v not sure? I purchased another as £9 each and even had the correct connector to plug straight in almost like it was made for it!
I've seen a Cambridge audio toroidal on eBay £25 with 2 outputs that may be useful but could be a waist of money. There is an audio grade on eBay for £48 but can offer rch engineering very helpful chap. Its 17-0-17 X2 and 7-0-7 approx.
Just wondering if I could use? I know the 30-0-30 is needed and 3v (to be measured) as separate transformers but the extra 17-0-17 approx (slightly higher) could supply the tube PSU?
Is this too risky? Adding the other transformer costs would still make it a good buy?
Is there anyone you can recommend a custom rewind that you use? Do you know rough costs?
You must measure them all for real first. Don't just take my word for it. Measure and confirm the values.
I know you want to experiment but I honestly think what you are proposing will end up messy even if it all works OK 🙂 although at face value the 17-0-17 should be OK for your valve PSU where 18-0-18 is mentioned. Preamps draw little current and the voltage from the transformer will probably be higher than specified under those conditions.
Sorry mooly I've should have been clearer🙂, I will definitely be measuring as I always do it's just sketching ideas and what's around but as you quite rightly say trying to fit all this in will be a challenge plus all the extra wiring and fuses. I do enjoy it though and I have lots of spare players and amps etc( to many!) . I like to design layouts, overcome problems and make everything neat and well routed( safety!!! ) I check the latest method of safety with 240v ensure connections heat shrinked and rubber below the PCB if metal chassis for switch, transformer connections etc. I haven't received cd-40 yet so can't start at the moment
Your advice is invaluable to me and given some inspiration!
I will get a quote for custom rewind I believe expensive.
Affectively there would be 3 transformers in place and one would be very small low voltage( wouldnt take much room up) .
I do have an 18-0-18 toroidal in stock to supply the tube PSU so can get that tested and in place and see results to begin with.
If I was to have custom rewind a could include the extra 18-0-18 for the tube providing its successful and sound quality what I was hoping.
Alternatively just rewind to spec as is and add separate 18-0-18 for tube. I prefer this.
Potentially you will have 2 medium tranny's with custom or 2 medium tranny's and a very small one with separate highest and lowest voltage plus the audio grade item mentioned with 3 take offs.
I personally would remove the webbing from the cd-40 empty compartment add metal shielding across the whole compart front to back. This will also strengthen.
The right hand compartment would have space to neatly install the tube PCB which I would also shield I think and have separate shielded compartment for the toroidals to supply everything. It adds strength again to. That's the theory anyway.
Until I've measured transformer and if say the lowest output is 3v it seems more difficult to obtain going from 240v down to 3v( example only) having looked but might be wrong?
need to get a quote definitely.
Whats your preferred equipment, mooly?
Your advice is invaluable to me and given some inspiration!
I will get a quote for custom rewind I believe expensive.
Affectively there would be 3 transformers in place and one would be very small low voltage( wouldnt take much room up) .
I do have an 18-0-18 toroidal in stock to supply the tube PSU so can get that tested and in place and see results to begin with.
If I was to have custom rewind a could include the extra 18-0-18 for the tube providing its successful and sound quality what I was hoping.
Alternatively just rewind to spec as is and add separate 18-0-18 for tube. I prefer this.
Potentially you will have 2 medium tranny's with custom or 2 medium tranny's and a very small one with separate highest and lowest voltage plus the audio grade item mentioned with 3 take offs.
I personally would remove the webbing from the cd-40 empty compartment add metal shielding across the whole compart front to back. This will also strengthen.
The right hand compartment would have space to neatly install the tube PCB which I would also shield I think and have separate shielded compartment for the toroidals to supply everything. It adds strength again to. That's the theory anyway.
Until I've measured transformer and if say the lowest output is 3v it seems more difficult to obtain going from 240v down to 3v( example only) having looked but might be wrong?
need to get a quote definitely.
Whats your preferred equipment, mooly?
Errata- I meant include the 18-0-18 for tubes in with the custom rewind? Its possible I guess but don't think I prefer as mentioned.
I really don't know what to suggest to you. My instincts say to stick with correct Marantz transformer simply because it is the perfect part for the job.
Although the preamp section of the valve preamp will use very little current and could probably be powered from the existing supplies in the player you also have the filaments (valve heaters) to consider and they will take a lot of current in comparison.
Although the preamp section of the valve preamp will use very little current and could probably be powered from the existing supplies in the player you also have the filaments (valve heaters) to consider and they will take a lot of current in comparison.
Thanks mooly, step at a time in other words.
Like said I have the correct toroidal for the tubes.
I will keep the marantz transformer and spend some time on other fruitful mods that are more cost affective. I need to listen to experience. The only possible consideration for the future is having an audiograde toroidal custom made to exactly the same specs.
Like said I have the correct toroidal for the tubes.
I will keep the marantz transformer and spend some time on other fruitful mods that are more cost affective. I need to listen to experience. The only possible consideration for the future is having an audiograde toroidal custom made to exactly the same specs.