On 18 Watt TW Liverpool Power Stack

[kryfcn]

Hi Ampgarage family. I’ve never been a member of any forum and Im new about building an amp. But thanks for the posts, i learned many things about tube amp building.
Im prof. Musician since last 15 years. Nowadays im trying to build 18 Watt Liverpool.Is there any Layout of the Power section ? Cap and Resistor values that i need to know. For the half watt Liverpool, correct rectification too. Is there critic values of the caps &resistors on the power section ? My Pt has 300v secondaries. Thanks for your help .



Koray

[kryfcn]

Hi Ampgarage family. I’ve never been a member of any forum and Im new about building an amp. But thanks for the posts, i learned many things about tube amp building.
Im prof. Musician since last 15 years. Nowadays im trying to build 18 Watt Liverpool.Is there any Layout of the Power section ? Cap and Resistor values that i need to know. For the half watt Liverpool, correct rectification too. Is there critic values of the caps &resistors on the power section ? My Pt has 300v secondaries. Thanks for your help .



Koray

[pdf64]

300VAC seems rather high, what’s the rectified VDC being supplied to the output transformer?

[thetragichero]

hello! check out post#2 here: https://ampgarage.com/forum/viewtopic.p ... 4&start=15

[kryfcn]

hello! check out post#2 here: https://ampgarage.com/forum/viewtopic.p ... 4&start=15

Thanks for the help i will work on it. Is there any Layout that makes the things easier for a beginner?

[kryfcn]

Thanks for help, 216 vdc now came down in 5 mins from 230 vdc .

[pdf64]

Something is desperately wrong there, what’s your light bulb limiter showing?
Twin TAG threads seems less than ideal, hopefully a mod can combine them.

[kryfcn]

Is there a solution and what can cause this problem? (if it is)

[kryfcn]

Something is desperately wrong there, what’s your light bulb limiter showing?
Twin TAG threads seems less than ideal, hopefully a mod can combine them.

When standby on, lightbulb gets little brighter. My tubes are redplating too in high volume. When the volume in 12 o clock its ok. After 12 o clock amp starts dropping volume and cutting the signal. In low volume sounds ok. Bass response is as good as it should be in low volume. İs my problem a simple bias issue? Or power section?

[pdf64]

It good that it's not staying permanently bright, but what wattage is the light bulb limiter's blub?
Before any loss / loading effects, a 300-0-300VAC HT winding should rectify to 424VDC, which is fed to the output transformer centre tap. To only get 216VDC there seems seriously wonky, I'd expect well over 400VDC.

You'll have to provide much more detail about your amp for anyone to be able to work out what's going on. eg accurate schematic, voltage survey, and multiple clear, well lit, detailed photos showing all the amp internals.

[pompeiisneaks]

They layout for the liverpool will work just fine, the only difference I see is the power section having 2 less tubes and 2 less components (don't need dual 220uF cathode caps and 130R cathode resistors, just one to tie the two together).

The linked schematic to the 18W is different by quite a few components from the original, so that's up to you if you want to keep the preamp identical to Ken's version or follow the other schematic linked above. I didn't note everything, but a few simple examples of differences I saw:

1MA pot for Bass instead of 250kb, 50pF/100pF bright cap options instead of 100pF/500pF and I did note a 33k grid stopper instead of a 820R to 2.2k for the original, etc.

I kinda stopped there realizing someone had taken the liberty on that build to change it quite a bit from Ken's original designs.

SO up to you as to what you're shooting for.

~Phil

[pompeiisneaks]

I also just merged the two identical posts in different sub-forums. Please don't do that... You'll get answers in whichever one you choose, but doing it in both isn't good etiquette on pretty much any forum.

I put this one in the trainwreck discussion area since it's about a trainwreck variant. You'll likely get more people to respond there since there are some forum members that tend to mostly focus on trainwrecks and don't read other areas as much.

~Phil

[dorrisant]

I would suggest to pull all of the tubes out and give us the voltages of the power tube sockets. Of particular interest is the voltage present on the #2 pins (bias voltage). This should be negative relative to the chassis.

If you can list the voltages by the pins it would be helpful. Remember, with EL84s, there is usually nothing on the unused pins 1, 6 and 8.

I agree with Pete that the HT on your power tubes seems wrong and the fact that your light bulb limiter is burning bright are an indicator that something is grounded that shouldn't be. Do realize that many amps will slightly flash the bulb on startup and should then fade to little to no light at all within seconds.

Can you post the schematic that you are working from. If it is not correct, we can get that sorted and perhaps find the correct layout as well.

Is this a kit? If so, model number? And any pics of your build in its current state may help a bunch.

Edit: my phone was not showing me Phil's posts. He is spot on in his comments. Sorry Phil.

[kryfcn]

Im sorry , i wish i could upload pics , and share with you guys but im working on my first built and im not on the greatest workmanship yet. But you guys will sure hear the sound. This project hopefully will be a full working prototype.
I measured my rectified voltage once again now my multimeter is showing its 270 vac.is that still low?
Plate voltages of El 84 : 259-261 v
After culculating outer el 84 has 10 Watt dissip.
inner el 84 has 6.2 watt dissip.
As i metioned Amp is working in half volume setting.after that, red plating and reducing the volume and strange noises coming out of it.
There is no short too. Tubes needs seprate biasing i guess. Which value of cathode res would be match for this plate dissipation wattages?
Thanks

[kryfcn]

I also just merged the two identical posts in different sub-forums. Please don't do that... You'll get answers in whichever one you choose, but doing it in both isn't good etiquette on pretty much any forum.

I put this one in the trainwreck discussion area since it's about a trainwreck variant. You'll likely get more people to respond there since there are some forum members that tend to mostly focus on trainwrecks and don't read other areas as much.

~Phil

Ah sorry guys that was mistake. I didnt exactly know where the subject should be .