- I plugged in the stock opamp and the turnoff noise disappeared, thanks! So for now seems the variables are opamps and the load at the output that's causing it.
- yeah you right I didn't put in those drop resistors at pre out, I think it should be irrelevant tho, for this particular headphone jack the pre out side of sockets are disconnected with headphones plugged in (I learned it the hard way after some time spent diagnosing why amp had no sound lol)
Hi there, I am thinking of building a Whammy in Japan which is 100V. Do you think the kit transformer will deliver enough juice or I should get a 100V one?
Sorry if this is a silly question, when wiring the AC to the power module terminals does it have to be wired a certain way or can either wire go on either tab?
Another WHAMMY on it's way!
After about a 15 year hiatus from DIY audio, I'm taking the plunge back in and building this hpa. (Back in my university days I built some kit speakers and a gainclone amp, you can see the amp in the background of one of my pictures below) After stumbling on to this thread I bought the full kit from the store and I'm slowly working my way through. I read through the contents of this monster thread while waiting for the kit to arrive and now I'm beginning my build. Posting some pics of my slow progress below, because why not? Thanks everyone (Wayne and 6L6 especially) for rekindling my love of this hobby 🍻☺️
Has anyone tried the WHAMMY as a preamp in front of a gainclone?
After about a 15 year hiatus from DIY audio, I'm taking the plunge back in and building this hpa. (Back in my university days I built some kit speakers and a gainclone amp, you can see the amp in the background of one of my pictures below) After stumbling on to this thread I bought the full kit from the store and I'm slowly working my way through. I read through the contents of this monster thread while waiting for the kit to arrive and now I'm beginning my build. Posting some pics of my slow progress below, because why not? Thanks everyone (Wayne and 6L6 especially) for rekindling my love of this hobby 🍻☺️
Has anyone tried the WHAMMY as a preamp in front of a gainclone?
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PSU section done. It turns on with no smoke. Measuring 16.91 and -16.94 for V+ and V- respectively. Onward and upward!
I had read in several places that the output stage of the Whammy could be operated directly with the full DC voltage, i.e. approx. 32V with a transformer with AC 2 x 22V or approx. +/- 26V with a transformer with AC 2 x 18V. Would that be okay?
Would I have to adjust the inner or outer 10k resistors for this?
Would I have to adjust the inner or outer 10k resistors for this?
IF you have an opamp that can accept that kind of voltage, yes. To get that rail voltage use 22VAC transformer and 7824/7924 regulators.
I wanted to supply the output stage directly with DC 32V or 26V from the CRCRC without a voltage regulator and the OPA normally via the 78/7915.
Since the voltage regulators get quite hot, I only wanted to use them to supply the OPAmp. The output stage then directly with the voltage from the power pack in front of the voltage regulators.
I'm also curious to see how the Whammy performs with this configuration.
I have two important questions, up to what voltage could the Whammy's output stage be operated?
Do I need to adjust the 10k resistors or others in the power amp section?
Thank you in advance for the help.
I'm also curious to see how the Whammy performs with this configuration.
I have two important questions, up to what voltage could the Whammy's output stage be operated?
Do I need to adjust the 10k resistors or others in the power amp section?
Thank you in advance for the help.
build it as is, one specimen
then build another, play with it and learn
at least you'll find first hand which ideas are good, which aren't
what your intention, in upper post, is to make it worse
then build another, play with it and learn
at least you'll find first hand which ideas are good, which aren't
what your intention, in upper post, is to make it worse
@Zen Mod
In fact, I've been doing this for over 25 years.
Whenever I tune a device or try different configurations, I always have an original device to compare with.
But I was hoping that someone could help me with my questions, mainly because the topic has been addressed several times in this thread, but unfortunately not in as much detail.
In fact, I've been doing this for over 25 years.
Whenever I tune a device or try different configurations, I always have an original device to compare with.
But I was hoping that someone could help me with my questions, mainly because the topic has been addressed several times in this thread, but unfortunately not in as much detail.
if you take Whammy OS from regulated rails, you'll loose some in S/N ratio department, which can be important when using cans; how much, only tests can show
now, if you increase rails (that being the reason to pull OS from reg rails), you;re certainly moving OS mosfets in voltage region where their intrinsic capacitances are more linear, and parts could work "more lively"
though, that being strictly academic, meaning that I can't tell how much of difference one could hear; intrinsic capacitance issues are pretty much miniimized with arrangement - parts working as source followers, where modulation between gate and source is minimal
of course, while increasing rails, you need to linearly increase resistances from rails to adjacent gates; meaning - if you increase rails for 50%, you need to increase said resistances for 50%
now, if you increase rails (that being the reason to pull OS from reg rails), you;re certainly moving OS mosfets in voltage region where their intrinsic capacitances are more linear, and parts could work "more lively"
though, that being strictly academic, meaning that I can't tell how much of difference one could hear; intrinsic capacitance issues are pretty much miniimized with arrangement - parts working as source followers, where modulation between gate and source is minimal
of course, while increasing rails, you need to linearly increase resistances from rails to adjacent gates; meaning - if you increase rails for 50%, you need to increase said resistances for 50%
Thank you, that helps me.
The resistors to be adjusted are the outer 10k (R6/R24/R25/R34)?
Starting from about 17V/10k, that would be about 15k at 26V and about 18.7k at 32V.
The resistors to be adjusted are the outer 10k (R6/R24/R25/R34)?
Starting from about 17V/10k, that would be about 15k at 26V and about 18.7k at 32V.
Progress update!
I was on vacation for a week so that delayed things. However, I’ve finished stuffing the PCB now and can begin mounting it in the case and wiring up the rest from there.
Turns on with no magic smoke coming out. DC offsets hover right around 6mV per side, so I’m happy to move forward!
🍻
I was on vacation for a week so that delayed things. However, I’ve finished stuffing the PCB now and can begin mounting it in the case and wiring up the rest from there.
Turns on with no magic smoke coming out. DC offsets hover right around 6mV per side, so I’m happy to move forward!
🍻
Attachments
Hello. I built a Whammy recently for a friend but he is getting some noise. He tested it for 30 minutes then it starting making a very loud screeching noise. Not sure if the op amp got loose or could it be something else? I tested this for several days before I shipped it out including voltages. I'm going to ask him to send some pictures. Any ideas what may be causing this?