What do you think about this tube schematic?

[DrFireBottle]

Where can I find cheap power transformers for EZ81?

First I want to say hi to all and I am new to the forum...
Thank you all in forward for replying to this!

Sorry for starting this again but I have some trouble finding transformers for the tube amps... (common problem because there are only a few companies manufacturing them).

I live in a poor family and i cannot afford everything I want... Plus i live in middle of nowhere on Balkans (Europe).

So if you have any knowledge of some good(and cheap) transformers please post it.

 

[Osvaldo de Banfield]

Which voltage (Primary, and secondaries)? Power? Size available?

 

[JMFahey]

In your situation, best by far is to hunt for old "grammophone/console" audio equipment, what used to be "the pride of the Living Room" some 50 years ago.
Think Grundig, Philips, Telefunken, etc.
Search pawnshops, charity places similar to Salvation Army, old attics, what would have Aunt Tanja used in her youth to listen to some music?
Then you can have transformers, sockets, maybe a usable chassis, for very little price or free.

 

[artosalo]

Have seen seen these: Transfer Multisort Elektronik - On-line Catalogue | 200 000 products offered.

 

[DrFireBottle]

Thank you all for replying...

I already have bunch of old radios and stuff but the problem is; those transformers do not have enough voltage for a beefy SSE(Two tubes in single ended) design.
Main reason why I make SSE is because i have a lot of SE transformers that i found in old radios and made a bargain with people on old stuff sales...

I need to have something that can put out 270-285 volts...
(I like to drive EZ80/81 alitte bit higher than the spec because of its mellowness when the B+ hits the power tubes...

 

[Shoog]

Consider a DC to DC booster from China - can be had for less than €10.00 and will do an excellent job.

Shoog

 

[JMFahey]

i have a lot of SE transformers that i found in old radios

Then you are talking small, cheap, limited range (definitely not Hi Fi) output transformers, barely handling 2W RMS ... there is not much you can do with them.
Nice for experiments , of course, but don´t expect miracles.

And the PT you pulled from those old radios is fine for the SE amplifier you can build with those OTs, by definition.

In fact, you have some spare filament current, maybe a little HV curret too, since you will not build the full radio but just the audio section.

 

[Eli Duttman]

DrFireBottle,

If you want a low cost/high performance B+ PSU, "full wave" voltage double the O/P of a Triad N-68X isolation trafo, using UF4007 diodes. 100+ mA. of B+ is available.

 

[kevinkr]

As Jim suggested I would probably use the power transformer from one of those Radios. I imagine shipping anything from the U.S. to the Balkans is going to be cost prohibitive. Have you considered sellers in the Ukraine, Bulgaria, Slovakia and the like - prices are good and the sellers IMVLE very honest, you can find them on eBay. (Russian and ex USSR military surplus) Shipping cost should be within reason.

 

[Osvaldo de Banfield]

Can't you get toroidal transformer from lighting services, for example, and rewind them? I did it some times. See my AM Tuner thread.

 

[kodabmx]

If you're willing to use solid state rectification you can get a Triad VPT230-????? with a 230V secondary from 25 to 1000VA. It will rectify up to 300V.

They start at about 20 CAD.

 

[FlaCharlie]

I already have bunch of old radios and stuff but the problem is; those transformers do not have enough voltage for a beefy SSE(Two tubes in single ended) design.

I need to have something that can put out 270-285 volts...
(I like to drive EZ80/81 alitte bit higher than the spec because of its mellowness when the B+ hits the power tubes...

If the power transformers from your old radios are only capable of powering a single channel, why not use two of them. If they provide enough current for both channels but not enough voltage you might consider connecting the secondaries in series. I've done that with a control transformer that had dual secondaries. You could build monoblocks (one channel in each chassis) or a single chassis with dual power supplies, one for each channel.

What circuit are you trying to build and what other tubes, besides the EZ80/81, are you planning on using?

I'm curious about your desire to run the EZ80/81 "higher than spec" and your perception that doing so creates more "mellowness when the B+ hits the power tubes". What spec are you exceeding? What circuit was this used in and what exactly do you mean by "mellowness"?

 

[popilin]

Just two more alternatives

1) Old valve TVs had huge power transformers

2) You can wind them yourself, for power transformer you do not need exotic cores, and for practice you can use those from old radios, I mean unwind and wind again... the second one is easier.

I am poor also and live almost in the middle of nowhere, this was a win-win solution for me, custom wound cheap transformers, the quality also depends on the love you put on them.

 

[samhill]

Not sure if this is in your budget, but it's in Eu, it's a nifty trany for a Mullard 3-3 or 5-10 or just about any EL84 & EZ81 amp. Nice it has the sperate heater winding for the EZ81 - or a 5Y3.

https://www.tube-town.net/ttstore/T...transformer-Marshall-Style-18-Watt::5989.html

 

[DrFireBottle]

Then you are talking small, cheap, limited range (definitely not Hi Fi) output transformers, barely handling 2W RMS ... there is not much you can do with them.

Yes of course, but I have some 6V6, EL84 radios that have 10-15W output transformers, and second... I am building an interesting dual EL86 guitar amp designed for nice cleans and crunchy reverb drived by 6AQ5... (surf rock amp)!

Thanks for the reply... Dock'tah Toob...

 

[Ketje]

In Europ you can find an low cost insulation transfo here TST100/028 INDEL - Transformer: toroidal | TME - Electronic components
Bridge rectifier on 230volts gives 320volts DC.For the heater put some extra windings on it (easy, it's a toroidal), more or less 10x / volt.Start with 11x and remove until 6,3 volts. The transfo is for 100VA giving space for much current.
Mona

 

[DrFireBottle]

Hi all, I hope you can have a look at this schematic that I designed and what do you think could be changed... This is an SSE (Dual Single Ended) power tube section that may can confuse others but it is just like a Push and Pull with a less power... The schematic was designed by me, but i took designs from all over the amp world... Little bit of Fender, Vox, and Magnatone.



Thank you in forward for replying!

 

[JonSnell Electronic]

Remove the 1nF cap across the anode load of the first stage and replace it with 470pF and 4k7 (in series).
Your NFB goes no where. place a 180R resistor at the top end of the cathode load and feed the NFB to the cathode. Watch out for a zero ohm potential across the NFB pot, may cause issues, place a 4k7 in series.
Otherwise it is a modified standard Fender but watch out for the anode voltage on the EL86s, they can't stand as much as an EL84.

 

[FlaCharlie]

Yes of course, but I have some 6V6, EL84 radios that have 10-15W output transformers, and second... I am building an interesting dual EL86 guitar amp designed for nice cleans and crunchy reverb drived by 6AQ5... (surf rock amp)!

Perhaps I'm confused. Is the amp you refer to in this thread as SSE the same "Surf Rock Amp" amp that you posted a schematic for over on the Instruments forum?

http://www.diyaudio.com/forums/instruments-amps/309342-what-do-you-think-about-tube-schematic.html

I thought your designation of SSE must stand for Stereo Single Ended and that this thread was about building a stereo amp, not a guitar amp.

The schematic you posted on the Instruments forum is typically referred to as PSE, Parallel Single Ended, since the output tubes are connected in parallel.

So, if you could clarify it would be helpful and you would likely get advise that is more useful to you.

 

[kevinr]

I just took this transformer from a working SCS power amp , would it help ?
It weighs 10 pounds. The amp had a treble oscillation issue

Also a torriodal from a working Samson Servo 160 power amp that had a Sanyo power chip failure