| Wavebourn |
Here is the PS schematics. Any comments/suggestions?
300 V regulated is to power screen grids and preamps.
 |
|
|
| Wavebourn |
Here is the box...
 |
|
|
| felixx |
| Hmmm...it looks good ...for now...but where is the main schematics?:D |
|
|
| Giaime |
Do I miss something in the face plate? :D
BTW, what are the advantages of a 2 mosfet regulator design, over a Maida regulator with LM317? |
|
|
| Wavebourn |
| quote: | Originally posted by felixx
Hmmm...it looks good ...for now...but where is the main schematics?:D |
Later... A bit of patience... (C) :D
| quote: | Originally posted by Giaime
Do I miss something in the face plate? :D
BTW, what are the advantages of a 2 mosfet regulator design, over a Maida regulator with LM317? |
Tell me what is Maida regulator with LM317, I will tell you what are the advantages of 2 mosfet regulator. :D
Here 0A2 gas discharge toob is a shunt - regulator of a reference voltage, Q2 is an error amplifier, Q1 is a source follower. Minimun of components and maximum functionality, including nice looking indicator of B+ presence. Here is the previous amp with similar regulator in the darkness:
 |
|
|
| astouffer |
| Where did you find GU-50 sockets? |
|
|
| felixx |
Please tell us about the sound comparing with triode DHT....and what topology is the main schm.
Thx. |
|
|
| Brian Beck |
| quote: | Originally posted by Wavebourn
Tell me what is Maida regulator with LM317, I will tell you what are the advantages of 2 mosfet regulator. :D |
Here's the original Maida HV regulator from National Semiconductor:
Maida HV regulator app note
These days , Q1 and Q2 might be replaced by a single high-voltage transistor, or by a power MOSFET. Simple and effective, if not state-of-the-art. |
|
|
| rdf |
| quote: | Originally posted by astouffer
Where did you find GU-50 sockets? |
Usually plenty on Ebay. |
|
|
| Wavebourn |
| quote: | Originally posted by astouffer
Where did you find GU-50 sockets? |
However, Soviet military originals are the best, but I was surprised by quality of Chinese sockets I bought on ePay. |
|
|
| Wavebourn |
| quote: | Originally posted by Brian Beck
Here's the original Maida HV regulator from National Semiconductor:
Maida HV regulator app note
These days , Q1 and Q2 might be replaced by a single high-voltage transistor, or by a power MOSFET. Simple and effective, if not state-of-the-art. |
It is the well known way to utilize low voltage regulator IC for a high voltage. Instead of LM317 may be used as well any 78XX ICs.
Probably I would go this way if I need better voltage regulation instead of nice glow of a gas discharge tube. :) |
|
|
| Wavebourn |
| quote: | Originally posted by felixx
Please tell us about the sound comparing with triode DHT....and what topology is the main schm.
Thx. |
The sound is like 6L6GC on steroids. :D
I'll draw the schem later, I have some sketches only.
The topology looks like Altec Lansing 1568 and 1569; I can't figure out anything better if to speak of push-pull tube amp. |
|
|
| Wavebourn |
Here is phase splitter schematics. Comments/suggestions?
I forgot to draw a resistor protecting a grid of bottom half of 6N1P from current, 100K with 39 pF paralleled.
|
|
|
| Wavebourn |
Hmmm....
Can't draw output stage and level indicator: no symbols for output transformer and 6E1P/EM80 tube in LTSpice... :( |
|
|
| felixx |
Try with another design program....or some schetch with an pencil...
The output trafo have 5k impedance? |
|
|
| Wavebourn |
| quote: | Originally posted by felixx
Try with another design program....or some schetch with an pencil...
The output trafo have 5k impedance? |
6K CT
I'll draw the tranny using available symbols
Also, no pots/trimpots in the library... |
|
|
| Wavebourn |
| quote: | Originally posted by soundbrigade
I have both the original article on Priboi and a shortened version in Swedish (my translation), so I don't need a translation.
However Zen-Mod was interested in a translation som Gospodin Welbourne or Gospodin Soundbrigade may give him the necessary points in the article off the list (PM).
Yepp the 6R3S is a tube wellknown for it's poor quality (very unreliable mehanically), so lets stick to the GU50! ;)
I've had my EC52/GU50 singing for some time and I am very happy. Sad the EC52 is such an odd tube, but isn't that half of the fun - to use odd looking tubes.
Next project would possible be a GU50PP., though I have some 6L6 (Russian brands) that would give some power to me. But anyway can anyone a rough idea how such an amp would look like, or could I use an outline for EL34 or 6550/KT88 with slight modifications? |
Hi Soundbrigade;
I am answering you in this topic since I feel like it is better for PP GU-50 amp discussion. I've opened the topic when desided to build a prototype of a GU-50 amp I successfully breadboarded. |
|
|
| Wavebourn |
I've opened a thread about group buy of transformers:
http://www.diyaudio.com/forums/show...&threadid=98678
There will be 100 W transformers, 10K CT primary, 30 Hz-20 KHz, secondaries for 4,8,16 Ohm.
I've contacted several manufacturers and hope I'll find good source of OPTs under $70 each.
I'm designing this amps for home audio, sound reinforcement, studio monitoring. However, for guitar amps such trannies will be an overkill, but for bass guitars they will fit more than perfectly! |
|
|
| soundbrigade |
I'll try to follow this thread, though I am leaving for a 5 week visit to mother Russia. Hope to fix my teeth (and that mrs. K will fix her and two passports) and that I will come home with a big heap of nice tubes (GU72).
I'd just say this as I ruined 4 GU50's - if using a tube without the "collar" be careful as the tube can be inserted in several ways. A sort of marker HAS to be made so you know how the tube must go.
This kind of socket/tubeholder is perfect:
 |
|
|
| Wavebourn |
Yes!
I mark Chinese sockets using a permanent marker.
 |
|
|
| Wavebourn |
I have some NOS Soviet military sockets...
 |
|
|
| soundbrigade |
| The lids were missing from my sockets.:xeye: |
|
|
| Wavebourn |
| quote: | Originally posted by soundbrigade
The lids were missing from my sockets.:xeye: |
I don't think you are going to use your amp in a bomber or any other vibrating environment. :D
The thing helps to dissipate a heat. I was thinking of putting heatsink collars around tubes... |
|
|
| Wavebourn |
I like it more with black painted grill...
 |
|
|
| soundbrigade |
| You are hiding them!!! You're sort of tube taliban keeping your beauties behind veils?! :) |
|
|
| Wavebourn |
| quote: | Originally posted by soundbrigade
You are hiding them!!! You're sort of tube taliban keeping your beauties behind veils?! :) |
I am hiding about a kilovolt from a sensitive human body! :dead: |
|
|
| Brian Beck |
| I like the key ignition. Is there a starter motor inside? :D |
|
|
| Wavebourn |
| quote: | Originally posted by Brian Beck
I like the key ignition. Is there a starter motor inside? :D |
There will be couple of end switches also, under the top lid and bottom cover. :D
The ignition key is to lock it when kids are near the amp. I want also to cover front toobs by a transparent plastic.
In the next version I am going to put GU-50 beauty in front of the grill, but under a transparent plastic.
|
|
|
| soundbrigade |
| quote: | | I am hiding about a kilovolt from a sensitive human body! |
You run them on quite a high voltage .... . Yeah, I noticed in my little book that they can operate on high anodevoltages. |
|
|
| Wavebourn |
| quote: | Originally posted by soundbrigade
You run them on quite a high voltage .... . Yeah, I noticed in my little book that they can operate on high anodevoltages. |
This one uses 750V, the next one will use 800V for GU-50 anodes. |
|
|
| Brian Beck |
| quote: | | The ignition key is to lock it when kids are near the amp. |
I seriously think that that's a good idea! |
|
|
| felixx |
@Wavebourn
Do you want to post the entire schematics?:D |
|
|
| Wavebourn |
| quote: | Originally posted by felixx
@Wavebourn
Do you want to post the entire schematics?:D |
It is too raw yet, far from the art. :D |
|
|
| soundbrigade |
I'm sorry wavebourn, but as you happen to be King of GU50's here you are the one to answer all questions about GU50 - here's one more.
I had a discussion with a Mr Anatolij M Lichnitsky in SPb about his modification of the Priboi amp. He had made a trial using EL34 in triode mode for the amp and admitted that GU50 could also be used.
Do you have any information on the Priboi amp and if GU50 instead of the rather flimsy 6R3S-I would work and maybe even bring it to new heights? |
|
|
| Wavebourn |
Sorry Magnus;
I am not a King yet, I am a Prince only. :D
First my GU-50 amp I built for a guitar when I was a teenager (in 1974) before I fell in love with transistors; and I did not touch them until last year when I tried them once and got 120W from one pair. I am still working on the amp, and as soon as get good repeatable results I will report them.
Speaking of Priboj, I did not touch any. However, I will try GU-50 tubes later in many different variants of voltages and currents, but now I have no experimental data. |
|
|
| Tweeker |
Hi Magnus,
| quote: | | Do you have any information on the Priboi amp and if GU50 instead of the rather flimsy 6R3S-I would work and maybe even bring it to new heights? |
The LS50 datasheet gives some information on triode mode. LS50 is the Telefunken design from which the GU50 was copied. It recommends no more than 400V anode and no more than 80ma idle current. I dont know how much if any GU50 and LS50 differ. |
|
|
| Wavebourn |
| quote: | Originally posted by Tweeker
Hi Magnus,
The LS50 datasheet gives some information on triode mode. LS50 is the Telefunken design from which the GU50 was copied. It recommends no more than 400V anode and no more than 80ma idle current. I dont know how much if any GU50 and LS50 differ. |
It means 4K plate load for 400V/80mA
-58V bias.
So, it will be happy with 450V plate source and 750 Ohm/5W cathode resistor. |
|
|
| agent.5 |
Wavebourn,
Are you using the GU50 as pentode or strapped triode?
Have you determined what is the maximum voltage for g2 if used as strapped triode?
http://www.mif.pg.gda.pl/homepages/.../018/g/GU50.pdf
I am reading that datasheet and it has a 250V max on g2.
Do you think g2 can take 400v to 600v as strapped triode? |
|
|
| Wavebourn |
| quote: | Originally posted by agent.5
Wavebourn,
Are you using the GU50 as pentode or strapped triode?
Have you determined what is the maximum voltage for g2 if used as strapped triode?
http://www.mif.pg.gda.pl/homepages/.../018/g/GU50.pdf
I am reading that datasheet and it has a 250V max on g2.
Do you think g2 can take 400v to 600v as strapped triode? |
I don't know, it is Telefunken data. I use them as pentodes with 300V regulatged on screens.
Sometimes manufacturers specify low max voltage on grids in order to achieve guarranteed linearity (an example is 6P15P for linear applications against 6P14P for audio).
I did not torture GU-50 yet so have no such experimental data; what I did, I increased VGs up to 300V and observed the grid. It was not red neither on iddle current, nor when the amp gave me about 120W of output power.
It is not enough for serious conclusions, but what is enough, I will certainly get 80W of very clean output power from pair of pentodes, as intended. |
|
|
| Tweeker |
Do you have any GU50 curves at 300V screen?
On GU50 and LS50 not quite matching, a GU50 triode curve. |
|
|
| soundbrigade |
Yabba dabba doooooooooooo!
Got hom from Russia tonight with 8 fresh GU50, 12 fresh 6S36P (OTL??), 5 6S4G and a load of smaller and bigger tubes of all kind.
Guess a PP-amp with paralelled GU50 would be a nice project. |
|
|
| Wavebourn |
| quote: | Originally posted by soundbrigade
Guess a PP-amp with paralelled GU50 would be a nice project. |
200W per channel? |
|
|
| soundbrigade |
Why not??!! Or as we say in Sweden_ when things are supposed to go to hell, they must to go to hell accompanied with music.:)
Seriously, I think I have some schematic for amplifiers using GU50 in parallel and just know that this Tsar Bomba can drive almost anything would be nice.
Beside I have 6 pairs 6P36S (6Pi36C) and had an idea that these could be used for an OTL-amp, but I have just gotten the tubes in my hand and haven't made any decision. I also have a bunch of 6S4S, G-807 and 6P43P that are a variation of 6P14P (EL84/6BQ5) that is supposed to be better. |
|
|
| Wavebourn |
| I thought of paralleled GU-50, but for another purpose: less load/less distortions. 100-160W/channel will be enough for my applications (high end vocal amps) |
|
|
| soundbrigade |
THAT sounds a good idea. Just like my Super-Priboi that runs very conservative with low V+, fully in ClassA and trioded to that.
When you get that far you have schematics or even maybe a working prototype - give us all details, will ya! |
|
|
| Wavebourn |
| quote: | Originally posted by soundbrigade
THAT
When you get that far you have schematics or even maybe a working prototype - give us all details, will ya! |
May be I'll give you kits including PCBs... :smash: |
|
|
| soundbrigade |
:eek: Sorry! I didn't mean ..... I just got carried away as I started to unpack my suitcases and scooped out all tubes I brought with me.
Talking 'bout tubes, I had to several times explain to the Russian customs personal what I had packed in my bags:
- What is that?
- Tubes, radiotubes.
- What's inside them?
- ???? Inside them??!! Nothing.
- What!!!???? Nothing???!!!
- Well, vacuum.
- Vacuum!? Well then everything's in order.... |
|
|
| Wavebourn |
| quote: | Originally posted by soundbrigade
:eek: Sorry! I didn't mean ..... I just got carried away as I started to unpack my suitcases and scooped out all tubes I brought with me.
Talking 'bout tubes, I had to several times explain to the Russian customs personal what I had packed in my bags:
- What is that?
- Tubes, radiotubes.
- What's inside them?
- ???? Inside them??!! Nothing.
- What!!!???? Nothing???!!!
- Well, vacuum.
- Vacuum!? Well then everything's in order.... |
You are lucky nobody invented yet a vacuum bomb! :eek:
Going from Hawaii back to California I had to throw out all liquids, including factory packed milk because some crooks in Great Britain figured out how to make a bomb mixing 2 liquid components! :hot: |
|
|
| Wavebourn |
Breadboarding a power supply... :smash:
 |
|
|
| Wavebourn |
Got output transformers:
 |
|
|
| soundbrigade |
Oooooooooooooooo! Sooooooo Bloooooo!
What do you think of Edcore's transformers. I have a pair of 2,5K SE (CSXE) waiting for some kind of tubes and a apir of 8K PP (XPP) that are driven by a apir of 6AQ5 - sounds fine. |
|
|
| Wavebourn |
| quote: | Originally posted by soundbrigade
Oooooooooooooooo! Sooooooo Bloooooo!
What do you think of Edcore's transformers. I have a pair of 2,5K SE (CSXE) waiting for some kind of tubes and a apir of 8K PP (XPP) that are driven by a apir of 6AQ5 - sounds fine. |
I think I have to try them ASAP.
:smash:
PS: you have already tubes for 2.5K SE: triode strapped GU-50 :D |
|
|
| soundbrigade |
| Or twin GU50 strapped as pentodes?! More power ....:) |
|
|
| Wavebourn |
Do you like this layout?
 |
|
|
| Cobra2 |
- there should even be space for a big cap in front of the power-trafo...
Arne K |
|
|
| Wavebourn |
| quote: | Originally posted by Cobra2
- there should even be space for a big cap in front of the power-trafo...
Arne K |
I am putting caps under the trafo :
|
|
|
| soundbrigade |
How about a bunch of 6C10P (6Ц10П) rectifier diodes as rectifier??
Where do you get sockets these days? |
|
|
| Wavebourn |
| quote: | Originally posted by soundbrigade
How about a bunch of 6C10P (6&10 ) rectifier diodes as rectifier??
|
No. I use DF10M bridge, small DIP body
| quote: |
Where do you get sockets these days? |
Old stock. However, Chinese sockets currently in production may be used, but they don't have alloy cups. |
|
|
| soundbrigade |
I have found newly (custom) made sockets at Röhrentecknik.de .
I also asked for an offer from a Russian company - Globex . |
|
|
| Wavebourn |
| quote: | Originally posted by soundbrigade
I have found newly (custom) made sockets at Röhrentecknik.de .
I also asked for an offer from a Russian company - Globex . |
Do you mean this one?
14 euro a piece! :eek: |
|
|
| soundbrigade |
Yeah, maybe. There was however another made in pertinax.
BTW - we are slightlöy off topic but GU50 is a tube for which you cannot get sockets from your local tube handler. I have some copies from a Russian book how to make certain detalis and components yourself - like tube sockets.
Gotta try to translate a little and fix the illustrations. |
|
|
| Wavebourn |
| When I was a teenager I made sockets for GU-50 out of military cable sockets. |
|
|
| Cobra2 |
| quote: | Originally posted by Cobra2
- there should even be space for a big cap in front of the power-trafo...
Arne K |
I was thinking more like this ;-)
Arne K |
|
|
| Wavebourn |
| quote: | Originally posted by Cobra2
I was thinking more like this ;-)
Arne K |
Wow! Nice! :)
I use 330 uF electrolytics + 4 uF metal films in parallel. |
|
|
| Tweeker |
Looks like somebodies been to the capacitor farm.
$12 for 80uF 500VAC polypropylene in oil motor run cap. |
|
|
| Wavebourn |
Do you like this chassis color?
 |
|
|
| soundbrigade |
Chassis colour:
I've been into black and red and now makes a sweep into blue and hammerite green (!!).
Your light red/orange doesn't make me blow any whistles, but why not. Do anyone have seen a green or yellow or brown (not wooden) amp??? |
|
|
| Wavebourn |
| quote: | Originally posted by soundbrigade
Chassis colour:
I've been into black and red and now makes a sweep into blue and hammerite green (!!).
Your light red/orange doesn't make me blow any whistles, but why not. Do anyone have seen a green or yellow or brown (not wooden) amp??? |
Front and rear panels will be charcoal black.
Also, there will be an option, rack mount box, black grill, something like this one: |
|
|
| Cobra2 |
The "thinwall" soket needs a 46mm hole, 38mm between mounting holes
Arne K
About chassi...I think I would prefer something more "quiet"...
And a hole for a bias-amp-meter?
(and vent-holes around the power-tubes?)
|
|
|
| Wavebourn |
Thank you for dimensions!
Do you mean a meter instead of EM-80 magic eyes?
Speaking of went holes, I think gaps between a tube an chassis will be enough. |
|
|
| Wavebourn |
Are you sure you need it?
And a hole for a rotary switch under the meter, right? |
|
|
| Wavebourn |
Here is it with a mirror between hot toobs and trafos.
 |
|
|
| pwan |
| quote: | Originally posted by Wavebourn
Do you like this layout?
|
May I have the spec of the OPT and the transformer ? Thanks. |
|
|
| jammer55 |
Hey Wavebourn:
Can you give contact info on a seller for the GU50?
Thanks |
|
|
| gerd |
| quote: | Originally posted by Wavebourn
Do you mean this one?
14 euro a piece! :eek: |
Hello, yes, but this sockets are made very nice, complex manufactured teflon milled pieces with high-quality spring loaded contacts from feather/spring bronze, with additional steel feather/spring for good contacting. The contact points are silvered, the soldering connections for good solderability even tinned after longer storage.
This parts was used in the old sockets from Siemens.
The sockets are screwed and you can change damaged parts.
Gerd |
|
|
| Wavebourn |
| quote: | Originally posted by pwan
May I have the spec of the OPT and the transformer ? Thanks. |
I forgot.
:bawling:
I did not touch this project half an year. |
|
|
| Wavebourn |
| quote: | Originally posted by jammer55
Hey Wavebourn:
Can you give contact info on a seller for the GU50?
Thanks |
I can't find it anymore in ePay feedback history. :xeye: |
|
|
| richwalters |
wavebourne #
Going back to the first schematic of the power amp psu, I notice you have no current limiting on the output i.e output Z is quite high and have to slug Low esr into a 470uF o/p relying on the 22R series resistor to take the surge up. On start up this is going to stew ?
As I see it, you are relying on the o/p cap (470uF) to keep psu ripple down, whereas if you split R1 i.e 10K then 47K and at the junction put a 22uF electroytic you will get another 40dB better ripple rejection and can reduce the value of the o/p cap.
Jay or nay ?
richj |
|
|
| Wavebourn |
| quote: | Originally posted by richwalters
wavebourne #
Going back to the first schematic of the power amp psu, I notice you have no current limiting on the output i.e output Z is quite high and have to slug Low esr into a 470uF o/p relying on the 22R series resistor to take the surge up. On start up this is going to stew ?
As I see it, you are relying on the o/p cap (470uF) to keep psu ripple down, whereas if you split R1 i.e 10K then 47K and at the junction put a 22uF electroytic you will get another 40dB better ripple rejection and can reduce the value of the o/p cap.
Jay or nay ?
richj |
1. I am relying on a resistor and Zener. Output Z is quite low because of feedback by voltage.
2. A gas discharge tube has more then zero dynamic resistance, so ripples are applied to both destination and source in the same polarity.
However, I can put an electrolytic there; also I can replace the resistor by a CCS, but what for? Also, I could use an opamp instead of a single FET, but actually I don't need more regulation.
3. I went with a simpler version, adding couple of Zeners in series with gas discharge tube, and using a single source follower, without any error amp. More than plenty of regulation as the result using much less of parts.
So, this one was as some people say, "Over-Engineered", I would call "Suboptimal". |
|
|
| Wavebourn |
| quote: | Originally posted by Wavebourn
Here is phase splitter schematics. Comments/suggestions?
|
This had changes as well:
R8 is 3 resistors 56K each in parallel, R10 and R11 -- both have 2 resistors 56K in parallel.
The second tube is 6N6P instead of 6N1P |
|
|
| soundbrigade |
| Wavebourne: I recall that you used something like 700V on the GU50. Would this splitter work with the OP-stage configured differently (lower high tension other anode load)? |
|
|
| Wavebourn |
| quote: | Originally posted by soundbrigade
Wavebourne: I recall that you used something like 700V on the GU50. Would this splitter work with the OP-stage configured differently (lower high tension other anode load)? |
I use the same to drive 6L6 tubes with 375V on plates.
Altec as I said before used very similar one in their 1568 and 1569 amps, it may be viewed as a Williamson phase splitter, but without one RC coupling network for better stability on low end. |
|
|
| soundbrigade |
| When I have cleared up/cleaned up my on/off-going projects I will look into stuffing some GU50s in my Priboi and try to get back some of it's old power. |
|
|
| beamnet |
As a fellow GU50 fan i'd like to ask about your experience with the sockets.
My tubes are REALLY hard to pull out. Ik have the metal bucket, but with the spring loaded contacts, not the milled round ones.
Bas |
|
|
|
