"Superfly" - submini tube version of Doug H's Firefly

Tube or solid-state, this section goes to eleven!
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pancho510
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Post by pancho510 »

hi I built the superfly with tone and volume and it sounds pretty good. but I think I have a issue. The power supply will only give me
150v max when amp is hooked up. i turn the trimmer pot about half way to get 150v but turning it more doesnt change the voltage any more.
If I take load(amp) off power supply then it will adjust normal i can get close to 300v and turn it down to about 185v but when put load back
on it drops down 150v. I built another power supply on a bread board with exact same results.oh another thing it does where ever the power
supply is set at, say 190v when i turn on amp i'll get a reading of 190v but will quickly settle to 150v in about 10 seconds. is the power acting
correct? if not I think I have a problem with amp I have went everthing several times checked all resistor values connection any help would
be appreciated. Thanks Frank

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frequencycentral
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Post by frequencycentral »

What's the mA rating of the power supply you're using? Should be at least 500mA. You can get the SMPS to give more volts by tweaking the resistors either side of the trimmer, if you do tweak do so in very small increments, as the SMPS can put out insanely high voltages until the magic smoke happens.

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pancho510
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Post by pancho510 »

thx for reply yes i have 2 different power supplies one is rated at .65 amps and other at 1.5a. i get same results from both.
I dont know anything about tubes. When i disconnect the heaters from circuit then power supply will adjust well over 200v
but connected i have problems drops to 150vmax.
today played amp sounds ok I put a distortion and delay pedal thru it and it sounded awsome.

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Ihunda
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Post by Ihunda »

pancho510 wrote:thx for reply yes i have 2 different power supplies one is rated at .65 amps and other at 1.5a. i get same results from both.
I dont know anything about tubes. When i disconnect the heaters from circuit then power supply will adjust well over 200v
but connected i have problems drops to 150vmax.
today played amp sounds ok I put a distortion and delay pedal thru it and it sounded awsome.
Hi pancho150, could you measure the current used by your circuit on the 200v line by plugging your multimeter in the middle of it (in series)?
Maybe you're drawing too much current from it due to solder joints or a mistake in the circuit.

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pancho510
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Post by pancho510 »

I checked the amps with the heaters and Im getting 16ma sounds very low without them 4ma.
I don't understand how the heaters work in the circuit. i get continuity thru the heaters not sure if that right
I was getting continuity from hot to nuetral via the heaters.
so i took them out of the circuit gave them thier own power supply that made it easier to trouble shoot.
So when I have B+ connected to amp circuit and the heaters 150vmax if I pull the heaters or the amp
circuit out B+ will rise up to well over 200v. i totally isolated the heaters wires from the board and rechecked
all connections again.

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JoaoSimoes
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Post by JoaoSimoes »

Hi everyone,

I have built the murder one amp and currently I am trying to build this one in a vintage way in a combo with battery.
I already have done that with the murder one and it turned out pretty cool. ( I have to post pictures)

What I am writing about is to see if someone can help me to make this amp with two channels.
Maybe doubling the preamp section (witch I believe will make the amp more dirty with only one power tube, but will be less power consuming)
or working with two preamps and to power tubes.
Can someone help? I am not got at all with electronics, but I am modestly good at building them (very good at lego or ikea :D)


Thanks for any help people!
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double head
double head

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Jayallen
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Post by Jayallen »

How would I go about modifying the output section to make this work with with a single ended transformer? I only have a hammond 1750a.this is what I have built so far.
2015-09-19 11.07.48.jpg
I just wired 1 & 8 together on tube 6111 for now. I got sound but not loud.Thanks.

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Thomas_H
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Post by Thomas_H »

Hi,
I tried the same thing with Rssian tubes.

Put both triodes in parallel. Both plates go to the transformar, while both grids receive the signal from the previous tube.
The cathodes are also in parallel.

The main changes are:
Since you're running the tube in parallel SE you need to reduce b+ to something like 130v and adjust the cathodes resistor to have the proper dissipation.

As I used russian tubes this values are different.
Good luck!
Thomas

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Thomas_H
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Post by Thomas_H »

Image

here is my parallelse schematic

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sneakers563
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Post by sneakers563 »

Seven years later...
I bought a 7327 for another project I'm working on and seeing as how there was some confusion back in the day about the specific characteristics of the tube, I ran it through my uTracer. Thought I'd share for posterity:

Characteristics and Typical Operation:
Va: 100
Vg: -2
Ia: 10.71 mA
Ra: 3.44 kohm
Gm: 5.63 mA/V
mu: 19

Va: 150
Vg: -5
Ia: 8.62 mA
Ra: 4.26 kohm
Gm: 4.48 mA/V
mu: 19

I've attached plate curves below. Sorry the grid resolution isn't better - it's one of the limitations of the otherwise great uTracer. Bottom line is that the 7327 is much more like the 6111 than the 6021. In a pinch, the 6111 datasheet will get you in the ballpark.
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jma38
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Post by jma38 »

frequencycentral wrote: 27 Aug 2009, 19:04 Here's the perf layout:

Image

Image
I'm building this and almost finished actually. Forgive a question that might sound stupid but where does the negative input from the guitar jack go on the board? I only see the input from the tip on the diagram. Great diagram by the way, it helped quite a bit while I was building this thing.

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tonyharker
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Post by tonyharker »

Ground

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jma38
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Post by jma38 »

tonyharker wrote: 31 Mar 2022, 22:09Ground
Yeah I thought of that, I just thought maybe one place on the ground line might be better than another. No problem though, I found a good place to solder it.
Have a good one

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jma38
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Post by jma38 »

Just a quick kind of newb question: Which way around do you put the 6112 and the 7327 in the sockets? I don't want to put them in backwards and ruin the amp.

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jma38
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Post by jma38 »

jma38 wrote: 01 Apr 2022, 16:57 Just a quick kind of newb question: Which way around do you put the 6112 and the 7327 in the sockets? I don't want to put them in backwards and ruin the amp.
Never mind I figured it out.

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jma38
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Post by jma38 »

So I built the Superfly but for some reason the tube heaters don't even light up. I've doublechecked everything and there's nothing wrong with the circuit soldered. My first thought is that if the tube heaters aren't even lighting up I must have put the tubes in backwards but I doublechecked where the pins are connected and it seems unlikely that that's the case.

What should I do to troubleshoot this?

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jma38
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Post by jma38 »

It turns out the amp isn't getting any power at all(thanks to testing with a multimeter). Everything points to the female power supply jack not being wired correctly so I'm working on that. Something's happening between that and the board which is keeping the DC power from flowing.

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