One thing to be aware of is the inductance of wire wound resistors. There did exist non-inductive variants tho. And, technically, the level of inductance should be somewhat negligible.
It would be interesting to hear from someone more well versed on that.
I also use metal film resistors for sub-50Hz CRCRC filter networks ... ... in low current power supplies for line stages, preamps, etc. For me personally, whenever I'm designing such a network and it seems to me that I want resistors rated for more than about 1.5 watts, I switch to metal oxide resistors rated 3 watts. And if 3 watt rating doesn't make me sufficiently comfortable, I switch to 5 watt wirewound types, in the rectangular cement package. But honestly that never happens ... ... in low current power supplies for line stages, preamps, etc. Like WHAMMY for example.
_
_
Last edited:
My understanding is that in power supply filters inductance is a good thing, perhaps desired.
That makes sense. So why prefer metal film?
In a preamp application I'm experimenting with CRC and was suprised to note that different filter resistors of same Rvalue resulted in a difference in sound. A regular vishay metal film PR02 5%-250ppm/C sounded worse than a TEC LR1 1%-low noise-50ppm/C, and the Vishay Wirewound RWM 5%-75ppm/C was worse also than the LR1 .
Yes, the TEC LR1 was low power but was in a 70mA quiescent buffer preamp, and handled the higher frequencies better. I would have predicted no difference in sound because they are the same value and not in the signal path -- or due to noise factors only, the ww RWM might sound best, but surprise... no.
It sounds like you've tried several alternatives and discovered one you like the most. Congratulations!
Thanks JimmyC23, PC997 & JermNZ.
It did take quite a little bit of effort in planning. Fitting in the burson is as simple as removing the 4 top cover screws and removing 1 screw at the coupler shaft for the input shaft. Total 5 screws.
But of course it would mean the top cover has to be left open.
This was the best compromise I could think of for an headamp that works both as a headamp and a preamp in a small form factor.
It did take quite a little bit of effort in planning. Fitting in the burson is as simple as removing the 4 top cover screws and removing 1 screw at the coupler shaft for the input shaft. Total 5 screws.
But of course it would mean the top cover has to be left open.
This was the best compromise I could think of for an headamp that works both as a headamp and a preamp in a small form factor.
Don't worry, it was just a joke, no-one says you need to use Bursons...
If you did want to try though, an adaptor like the one below might be an option! Or even for standard IC op-amps it might make it easier to switch in and out.
If you did want to try though, an adaptor like the one below might be an option! Or even for standard IC op-amps it might make it easier to switch in and out.
haha no worries! No offence taken. Didn't meant to be defensive.
And yes that looks like a great idea. Maybe it's time to buy one or two Bursons to play with hehe.
And yes that looks like a great idea. Maybe it's time to buy one or two Bursons to play with hehe.
This may be too simple a question, to achieve a balanced Whammy, can you simply used two boards (dual Whammy)
Can't this simply be 2 boards, one for the left and one for the right channels with a common ground signal, connected to earth via a safety CAP?
Unbalanced inputs and outputs can then be via cable adaptors?
Can't this simply be 2 boards, one for the left and one for the right channels with a common ground signal, connected to earth via a safety CAP?
Unbalanced inputs and outputs can then be via cable adaptors?
Balanced Whammy
Thanks rikiheck, I thought so.
The other elements I can think of are an input switch to toggle between the RCA and XLR.
A balanced jack that mutes the unused channels and an accurate (shunt) quad attenuator?
Am I missing anything (apart from the cost)?
I know this may not bring much improvement to an already great design, but
I just love the challenge of the exercise.
Thanks rikiheck, I thought so.
The other elements I can think of are an input switch to toggle between the RCA and XLR.
A balanced jack that mutes the unused channels and an accurate (shunt) quad attenuator?
Am I missing anything (apart from the cost)?
I know this may not bring much improvement to an already great design, but
I just love the challenge of the exercise.
I've thought about doing this, too. Matching the parts to get proper symmetry will help, too. Whether it's worth it is hard to say.
Decided to swap out the 22V xformer for an 18V. The naked regs run so much cooler haha.
I'm guessing there's no concern for sag even with power hungry planars like the LCD-4? It seems the LCD-4 isn't crazy hard to drive, but being 200 ohms, seems to require an interesting mix of both voltage and current to make its driver come alive.
Hi!
The whammy is the first ptoject I finish, and yesterday I did my firsrt experiment on it, changing c1 and c5 for some good polypropilene caps. I write this because I honestly thought that the difference was going to be very very subtle, and to be honest, "without being night and day" difference I have to say it´s definetly an improvement specially in the treble region.
I´m new to this hobby and don´t know very well how to describe the changes in the sound, but I find the trebble to be more prominent and also have better placement of instruments... like everything walks around your head and different instruments sound in different places, something I wasn´t so aware before.
These are the caps I´ve used, expensive for sure, but for me it has been worth just for the experience of noticing a change in sound because of this. I wasn´t expecting it.
MUNDORF MCAP SUPREME Capacitor 600V 1μF - Audiophonics
The whammy is the first ptoject I finish, and yesterday I did my firsrt experiment on it, changing c1 and c5 for some good polypropilene caps. I write this because I honestly thought that the difference was going to be very very subtle, and to be honest, "without being night and day" difference I have to say it´s definetly an improvement specially in the treble region.
I´m new to this hobby and don´t know very well how to describe the changes in the sound, but I find the trebble to be more prominent and also have better placement of instruments... like everything walks around your head and different instruments sound in different places, something I wasn´t so aware before.
These are the caps I´ve used, expensive for sure, but for me it has been worth just for the experience of noticing a change in sound because of this. I wasn´t expecting it.
MUNDORF MCAP SUPREME Capacitor 600V 1μF - Audiophonics
Mosfet Alternatives
Hi all
Putting together a parts list for the Balanced Whammy project.
Per 6L6 original BOM
" 2) P Mosfet Q2 Q4 2SJ313 May also use IRF9610, FQP3P20 Fairchild - 512-FQP3P20 Vishay - 844-IRF9610PBF
(2) N Mosfet Q1 Q3 2SK2013 May also use IRF610, FQP3N30 Fairchild - 512-FQP3N30 Vishay - 844-IRF610PBF..."
Would these work as alternates for the Mosfets?
Are there any disadvantages from
Q1, Q3: IRF510PBF-BE3
Q2, Q4: IRF9510PBF-BE3
thanks
Hi all
Putting together a parts list for the Balanced Whammy project.
Per 6L6 original BOM
" 2) P Mosfet Q2 Q4 2SJ313 May also use IRF9610, FQP3P20 Fairchild - 512-FQP3P20 Vishay - 844-IRF9610PBF
(2) N Mosfet Q1 Q3 2SK2013 May also use IRF610, FQP3N30 Fairchild - 512-FQP3N30 Vishay - 844-IRF610PBF..."
Would these work as alternates for the Mosfets?
Are there any disadvantages from
Q1, Q3: IRF510PBF-BE3
Q2, Q4: IRF9510PBF-BE3
thanks
Hi all,
I am loving my WHAMMY.
Thanks to Wayne for his wonderful creation and 6l6 and all the great input from everyone.
What fun.
I had the great opportunity to have had all the thinking and most of the work done for me
from passive420. Thanks. 🙂
I just had to finish off my upgraded amp.
As it was the first time I had done anything like this, it was a brilliant opportunity.
Boy am I pleased I chose this one.
So, I have now realised that I can also use this as a preamp.
Firstly, I am not sure I need a preamp.
But I think I do 🙂
I have tried reading through looking for preamps.
I am trying to work out my options and would love some help please.
It seems like the simplest one is with a switched headphone jack. Is that right?
With a 50Ohm resistor. If I read the right bit.
Are there pros and cons to this method?
Is there a better (quality wise) way?
I assume I just run RCA cables from the switched headphone jack to my amp?
Then, where exactly do I put the resistors please?
Thanks
Edit: Found the oft recommended switch:
MJ6HFD2 Neutrik | Mouser United Kingdom
I am loving my WHAMMY.
Thanks to Wayne for his wonderful creation and 6l6 and all the great input from everyone.
What fun.
I had the great opportunity to have had all the thinking and most of the work done for me
from passive420. Thanks. 🙂
I just had to finish off my upgraded amp.
As it was the first time I had done anything like this, it was a brilliant opportunity.
Boy am I pleased I chose this one.
So, I have now realised that I can also use this as a preamp.
Firstly, I am not sure I need a preamp.
But I think I do 🙂
I have tried reading through looking for preamps.
I am trying to work out my options and would love some help please.
It seems like the simplest one is with a switched headphone jack. Is that right?
With a 50Ohm resistor. If I read the right bit.
Are there pros and cons to this method?
Is there a better (quality wise) way?
I assume I just run RCA cables from the switched headphone jack to my amp?
Then, where exactly do I put the resistors please?
Thanks
Edit: Found the oft recommended switch:
MJ6HFD2 Neutrik | Mouser United Kingdom
Last edited:
