[OJNeg]

That sounds like quite a PITA, but I'm interested to see for myself eventually.

 

[dsavitsk]

You are going to run into two issues -- oscillation and operating points. For operating points, getting sufficient voltage drop across both the tube and the CCS while maintaining grid voltage will be the issue. It may be possible, but you'll have to play with it. If you don't it will clip horribly and may well draw grid current. Also, note that the 6C45 needs sufficient current to generate its high gm. If the current is too low, the rp will be high enough that it is not doing you any good to use. It is a delicate balance, and the Torpedo's PS may not be quite up to the task.

As for oscillation, it will without precautions. That means grid stoppers on each grid, a plate stopper, and 4 cathode stoppers. The reason for 4 cathode stoppers is so that each can be large enough to quell oscillation while all 4 in parallel will be low enough to not drop too much voltage. The stoppers really should be SMD and should be touching the socket pins. Leaded resistors may work on some tubes, but they do not work nearly as well as you simply can't get them close enough. I also found that teflon tube sockets helped.

All of that means that you probably should make small PCBs with the stoppers in place. It is the most likely to lead to success. Oscillation will result in the tube sounding etchy, brittle, bright, etc -- all the things people criticize it for sounding like. Let us know how it goes.

 

[Wsybok]

Hey,
I just finished build my Torpedo, when i test it, everything seems like good, 4 leds light up, tubes heated up without any problem.
But when came to the last step, i plugged my T90, there was no sound output, and when i use my phone as signal source, there was very very low voice(nearly no sounds ) coming out, but the volume stay constant no matter how i turned potentiometer.
Is any one know which parts that may cause this kind of problem?? Than you.

 

[tomb]

Hey,
I just finished build my Torpedo, when i test it, everything seems like good, 4 leds light up, tubes heated up without any problem.
But when came to the last step, i plugged my T90, there was no sound output, and when i use my phone as signal source, there was very very low voice(nearly no sounds ) coming out, but the volume stay constant no matter how i turned potentiometer.
Is any one know which parts that may cause this kind of problem?? Than you.

Are you international or domestic?  Check the jumpers at the power transformer and be certain you soldered the correct ones.  If you're operating at half-voltage, your description is valid, but you will get very little sound.

 

[PretentiousFood]

Hey Doug, I've seen you mention the stoppers in a few posts across the web. Grid stoppers are pretty routine, but I haven't seen much mention of plate stoppers elsewhere. Its the plate's capacitive coupling to the inputs more of an issue in high gm tubes, or is it something else entirely? How would you go about sizing the resistors?

 

[Wsybok]

Are you international or domestic?  Check the jumpers at the power transformer and be certain you soldered the correct ones.  If you're operating at half-voltage, your description is valid, but you will get very little sound.

Well, i jumped A to B and C to D for 120v input, is that correct?

 

[tomb]

 

Are you international or domestic?  Check the jumpers at the power transformer and be certain you soldered the correct ones.  If you're operating at half-voltage, your description is valid, but you will get very little sound.

Well, i jumped A to B and C to D for 120v input, is that correct?

Not if you're international.  If US, then that's OK.
 
Check the following:
1. Diodes in their correct positions?
2. Resistors in their correct positions?
3. Transistors oriented correctly? (TO-220's have their lettering facing out from the heat sink.)
 
To remove my packaging as a potential source of error, check these parts with the BOM and the silkscreen values on the PCB directly.  Measure the color-coded resistors, read the values of the V-D resistors (assuming you soldered them with the value indication up.)
 
The Torpedo is not very complicated, circuit-wise.  Most of the ingenuity is in layout, parts selection (including the tubes), and transformer design.  That should make it easy to troubleshoot.  The transformers are impossible to solder in the wrong orientation - so are the RCA jacks, the volume pot, the tube sockets, and the headphone jack.  That leaves transistors, resistors, and diodes. (Capacitors soldered incorrectly will blow.)
 
If none of that indicates a problem to you, then it's time to post some pics.

 

[Wsybok]

Not if you're international.  If US, then that's OK.

Check the following:
1. Diodes in their correct positions?
2. Resistors in their correct positions?
3. Transistors oriented correctly? (TO-220's have their lettering facing out from the heat sink.)

To remove my packaging as a potential source of error, check these parts with the BOM and the silkscreen values on the PCB directly.  Measure the color-coded resistors, read the values of the V-D resistors (assuming you soldered them with the value indication up.)

The Torpedo is not very complicated, circuit-wise.  Most of the ingenuity is in layout, parts selection (including the tubes), and transformer design.  That should make it easy to troubleshoot.  The transformers are impossible to solder in the wrong orientation - so are the RCA jacks, the volume pot, the tube sockets, and the headphone jack.  That leaves transistors, resistors, and diodes. (Capacitors soldered incorrectly will blow.)

If none of that indicates a problem to you, then it's time to post some pics.

Yes, I am using it in US.
I will check those tonight,
Thanks for your help.

 

[dpump]

Wsybok,
 
Check beside the volume control to make sure you soldered the 2 jumpers there on the pcb.

 

[Wsybok]

Wsybok,

Check beside the volume control to make sure you soldered the 2 jumpers there on the pcb.
[/

Wsybok,

Check beside the volume control to make sure you soldered the 2 jumpers there on the pcb.

Dpump
Thanks for your advise, but I can't find any jumpers beside the volume control.

Are there still jumpers beside the volume control on v1.02?

 

[dpump]

Sorry, you are correct- no jumpers. I was thinking of my pcb which is an earlier one.

 

[Iskandar Pane]

Hello I'm new on this forum and I think I have a related problem with the torpedo. I finished building the torpedo yesterday. I made some other Diy project and I am very impressed about the quality of the pcb, and how everything was packed.

After finishing everything, I put on the power. The red leds lit up but within a few seconds they went out. Because I live in Europe (the Netherlands) I use jumper setting b-c 240v. I checked everthing, all components in the right place. When the leds went out, there where no strange noises, nothing smoked, the fuse still ok.

I can measure a voltage of 230v in the primary windings of the powertransformer, but no DC on the 2 secondary windings. I desolderd the PT, cleaned all the pins (coating) and soldered the PT back on again to be sure all the connections are good. Fortunately, no result.

Do I have bad luck with a new, but broken powertransformer? Can I measure the PT with a multimeter if this is the case? Is it something else? I hope someone can help me (tombe).

Thnx

Iskandar

Not if you're international.  If US, then that's OK.

Check the following:
1. Diodes in their correct positions?
2. Resistors in their correct positions?
3. Transistors oriented correctly? (TO-220's have their lettering facing out from the heat sink.)

To remove my packaging as a potential source of error, check these parts with the BOM and the silkscreen values on the PCB directly.  Measure the color-coded resistors, read the values of the V-D resistors (assuming you soldered them with the value indication up.)

The Torpedo is not very complicated, circuit-wise.  Most of the ingenuity is in layout, parts selection (including the tubes), and transformer design.  That should make it easy to troubleshoot.  The transformers are impossible to solder in the wrong orientation - so are the RCA jacks, the volume pot, the tube sockets, and the headphone jack.  That leaves transistors, resistors, and diodes. (Capacitors soldered incorrectly will blow.)

If none of that indicates a problem to you, then it's time to post some pics.

 

[Wsybok]

 
Not if you're international.  If US, then that's OK.
 
Check the following:
1. Diodes in their correct positions?
2. Resistors in their correct positions?
3. Transistors oriented correctly? (TO-220's have their lettering facing out from the heat sink.)
 
To remove my packaging as a potential source of error, check these parts with the BOM and the silkscreen values on the PCB directly.  Measure the color-coded resistors, read the values of the V-D resistors (assuming you soldered them with the value indication up.)
 
The Torpedo is not very complicated, circuit-wise.  Most of the ingenuity is in layout, parts selection (including the tubes), and transformer design.  That should make it easy to troubleshoot.  The transformers are impossible to solder in the wrong orientation - so are the RCA jacks, the volume pot, the tube sockets, and the headphone jack.  That leaves transistors, resistors, and diodes. (Capacitors soldered incorrectly will blow.)
 
If none of that indicates a problem to you, then it's time to post some pics.

tomb,
I found that I forgot solder the SMD Capacitors on the back side of PCB, however it's still have same problem when I soldered those Capacitors on. (the volume stay same no matter power on or off).
I will upload some pics tomorrow.
and again, thank you for your help.

 

[UKToecutter]

Hello I'm new on this forum and I think I have a related problem with the torpedo. I finished building the torpedo yesterday. I made some other Diy project and I am very impressed about the quality of the pcb, and how everything was packed.

After finishing everything, I put on the power. The red leds lit up but within a few seconds they went out. Because I live in Europe (the Netherlands) I use jumper setting b-c 240v. I checked everthing, all components in the right place. When the leds went out, there where no strange noises, nothing smoked, the fuse still ok.

I can measure a voltage of 230v in the primary windings of the powertransformer, but no DC on the 2 secondary windings. I desolderd the PT, cleaned all the pins (coating) and soldered the PT back on again to be sure all the connections are good. Fortunately, no result.

Do I have bad luck with a new, but broken powertransformer? Can I measure the PT with a multimeter if this is the case? Is it something else? I hope someone can help me (tombe).

Thnx

Iskandar

Ummm...
 
I think you should be looking for AC on the Power Transformer secondary, not DC.

 

[Iskandar Pane]

Yes, I was wrong, its AC, but still nothing...