"Murder One" Submini Tube Guitar Amplifier

[dean8020]

This project ended up getting put on a shelf half finished for a few months.

Finally got it finished this weekend, apart from a problem with the power supply, which I am asking for help on,
After I bolted the lot in the case the B+ dropped to ~6V rather than 60V
And I cannot for the life of me figure out why, I've had it back out the case and all over, Ive tried brand new IC's and also rebuilt a new one on breadboard with the same outcome.

Does anyone know what that could be, I still don't know how the power supply is working, I was just glad to find one that did.

Also to Rick, would you be willing to sell just a power supply made up and working???


Anyway, I have ran some leads from B+ out of the back of the case to a bench power supply providing 62V for now

I Redesigned the preamp stage with the 6111's
and paralleled 2 of the output stages

New Preamp:


And here is my project.











I discovered I'm not to good at sticking letters on things

Oh well,

Here is a link to the vid of it,

Audio recorded with a Rode NT55

[theItalianDiYer]

hi rick!!!
i was wondering if you could add the bright switch (bright/normal) and a thickness switch (normal/thin/fat), like a nano head!!!

a friend of mine asked if I could build one for him...now i've ordered some 6111 from America beacuse they're not avaiable in italy!!!

best regards!

[frequencycentral]

Sure, try it! Though I've never added tone controls to the M1 because they suck volume.

[thereminator]

Nice, but too big.
Chassis is the same large as 5watt amp with "normal" noval tubes.

[pancho510]

I built the murder one amp but not getting any sound. Im a newbie to this.
here what I have first im using a 12v dc power supply not sure if this is correct?
I notice on scematic it shows 12v input and on pin 3 on both tubes +12 volts. I connected all 12v to the same point is this correct?
also 6111 heats up but 5672 nothing at all.
I checked for voltages and im getting 12v at input.
5.6dc at point B+ to ground no ac voltage
also getting 5.6vdc to ground on pin 1 of 5672 and 0v from pin 1 of 5672 and B+.
im not getting no sound or humming ,crackle nothing
i've check everything not sure how to trouble shoot where to start any ideals
thanks

[frequencycentral]

im using a 12v dc power supply not sure if this is correct?

Thta's correct. 12vdc regulated.

I notice on scematic it shows 12v input and on pin 3 on both tubes +12 volts. I connected all 12v to the same point is this correct?

Yes, but each via a voltage drop resistor. Note the values AND wattage rating - the resistors drop voltage by making it into heat.

also 6111 heats up but 5672 nothing at all.

6111 will glow nice and orange, and feel warm. 5672 will do neither because the heater voltage/current is so low.

5.6dc at point B+ to ground no ac voltage
also getting 5.6vdc to ground on pin 1 of 5672 and 0v from pin 1 of 5672 and B+.
im not getting no sound or humming ,crackle nothing
i've check everything not sure how to trouble shoot where to start any ideals
thanks

From what you have written I'm not entirely convinced you have the 220R 1W and 18R 2W resistors hooked up between 12v and the tubes' heater. Also sounds like your MAX based voltage multiplier is not functioning. Try disconnecting it from the amplifier part of the circuit and measure the output voltage.

[pancho510]

From what you have written I'm not entirely convinced you have the 220R 1W and 18R 2W resistors hooked up between 12v and the tubes' heater. Also sounds like your MAX based voltage multiplier is not functioning. Try disconnecting it from the amplifier part of the circuit and measure the output voltage.

I have both R4 and R5 hooked up
I disconnected the wire from pin 5 on 7660s and disconnected wire from R3 to diode/cap and took a voltage
reading from diode/cap to ground im getting 11v dc im also getting 10.7vdc on pin 2 to ground of 7660

[pancho510]

figured it out I read scematic wrong i had D13 tied from pin 3 on 7660 to 12v. I grounded pin 3 and D13
still have some minor issues but it works thanks for your help

[theItalianDiYer]

Sure, try it! Though I've never added tone controls to the M1 because they suck volume.

yes, I think so. Maybe you could increase the ouptut volume (if the penthode allows you), but I don't know how to do it...

for the Thickness control I think thar you can change the value of the input cap...

best regards..

[pancho510]

ok I got sound but there was a very high hum so I switched the 7660 out for a 1044 hum went away.
I believe I still have some issues but not sure. it sounds good at full volume and gain but not very loud
also there's not much play with the volume or gain if I turn either one down from 10 to about 6 I get
no sound at all. I checked the voltage B+ to ground and I get 53Vdc not ac.I thought this should be
around 70-80 volts AC.with the 7660 I get around 30Vdc.

[luichi]

GreetingsLet's see, I have just mounted the project and I have several doubts:
I have the amplifier connected to a little cone ( a little in bad shape, but new ) of 8 ohm and 3 "eWhen connect it nada.Tengo that to put it with volume as much as possible and the gain are not heard to low volumes as much as possible in order that it break down completely and sound but to an enough low volume ( to be as much as possible )hWith the vol as much as possible and taking the gain down I lose very much vol and taking the vol down to them 2 and from there stops I get down no longer you hear nothing ...vI have once the v6 with a 7660 cpa1113 of maxi-m was mounted originally there was the 7660cpa0905 riddenly and it was out of service .tCan it be the chip?hThe other option that happens to me is salida.es's trafo a hammond 125A.Lo I have connected with the brown cables and red disconnected azul.El and the way out to the pins2 and 4 just as they indicate the trafo's specificationsw
Http://www.hammondmfg.com/125.htm
Somebody does come up with it where I can have the error?
thanks

[derevaun]

Sorry to necro this thread! I'm starting a Murder One, and am thinking I want to have the power supply on a separate board, in order to have more freedom WRT space in the enclosure, and to more easily sort out potential bugs. I figure I'll connect the ground from the speaker jack to a point close to the ground of the first cap (C16), and connect the ground from the main circuit to the same point, or somewhere else. My question is: would that create a potential ground loop situation? Where is a good point to connect the main board ground wire?

Thanks for any guidance, pity, or pointing-out-of-the-obvious!

[Ihunda]

The 7660 lacks the oscillator frequency boost feature which the MAX1044/TC1044/LTC1054 feature. That means the oscillator frequency is within the range of human hearing, ie. it'll whine like a bitch! I've tried it. The frequency boost feature allows the oscillator to run at 50kHz IIR. Your pet dog/bat/mosquito may not be happy but you'll have a good sounding amp.

It is possible to externally clock the 7660 to get it running above the range of human hearing, but the extra circuitry does not make this as neat a solution as just getting the right charge pump for the job.

Well, according to the datasheet here: http://www.intersil.com/data/fn/FN3179.pdf, the ICL7660S can be boosted to 35Khz if V+ is plugged to pin 1. Isn't that high enough?

[frequencycentral]

The 7660 lacks the oscillator frequency boost feature which the MAX1044/TC1044/LTC1054 feature. That means the oscillator frequency is within the range of human hearing, ie. it'll whine like a bitch! I've tried it. The frequency boost feature allows the oscillator to run at 50kHz IIR. Your pet dog/bat/mosquito may not be happy but you'll have a good sounding amp.

It is possible to externally clock the 7660 to get it running above the range of human hearing, but the extra circuitry does not make this as neat a solution as just getting the right charge pump for the job.

Well, according to the datasheet here: http://www.intersil.com/data/fn/FN3179.pdf, the ICL7660S can be boosted to 35Khz if V+ is plugged to pin 1. Isn't that high enough?

The 7660 lacks the oscillator frequency boost feature which the MAX1044/TC1044/LTC1054 feature.

The 7660S has the frequency boost feature.

Check, 7660S are also cheaper, easier to get in the UK, and have a higher maximum input voltage. My latest build notes on the previous page uses ICL7660S - just make sure you order the S suffix type, or your amp will attract bats and dogs.

[Ihunda]

Thanks, I should have gone through all pages before answering that post

[kleuck]

The latest "Murder One" Submini Tube Guitar Amplifier. This one is already SOLD, I'm building a few more identical if anyone's interested in owning one.

Beautiful !

[frequencycentral]

Thanks! That's such an old one, they look like this now:





The circuit has changed a lot over the years too, now I'm on Version 7 - I'm such a tweaker. It dispenses with the bias switch and associated circuitry. It also includes (orange) pads and swiching diagram for adding a pre-out using the existing speaker out socket - it basically takes a tap from the preamp stage and also cuts power to the pentode when switched to pre-out mode. If you dont want the pre-out switch you'll need to jumper the orange pads together.:





...sounds like this:

http://dl.dropbox.com/u/967492/Murder%2 ... ontage.mp3

The amp was driving a Marshall 1936 2×12. No other effects except a little SHO boost for the ‘shredding’ part, and a touch of reverb. Microphone was a Shure SM58.

[Ihunda]

So I have been receiving parts to build that amp and I have been reading books about tube preamps and output stages to get ready for it.

I received my 5672 first and to my surprise, there's no cathode lead! I was going through the datasheet trying to calculate bias and all. Well from what I understand of the datasheet you pretty much have to follow the typical operating point as it seems that the valve is kind of "hardcoded" for this operating point.

I am right to assume that both cathode and supressor gride are connected to the - terminal of the heaters?
So this means there's no way to bypass the cathode for maximum gain?
Would it make sense to bypass the screen partially and setup a treble boost pot in there?

Thanks for your help guys,

IHFX

[Ihunda]

A little bumping never hurts..

[Leodos]

Hi guys.
I'm very interested in making a mini amp (v 6), but I have a couple of questions.
The capacitors are 50 v?
The IC may be the next link? http://cl.rsdelivers.com/product/inters ... 46707.aspx
The box is a Hammond 1590BB?
My idea is to use it in combination with a Vox Tonelab ST and 2x12 Cabinet....
Thank you very much.