Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Paul1453 on March 09, 2016, 06:46:44 pm
-
Tubenit,
Thank you.
I just wanted to make sure I was respectful to the amount of work you put into designing and laying out this circuit. :icon_biggrin:
I am beginning to understand just how much work that really is.
Anyway, you are one of the people here who have learned how to do things most would shy away from. :worthy1:
If you wanted, I would be happy to ship you a pair of Mullard SQ E130L tubes free of charge. :icon_biggrin:
These are tubes that came out of my pulse generator purchases.
They are audio tubes capable of 60W output in AB PP operation.
They are not commonly used in audio amplifiers though.
I have had a hard time finding any type of E130L audio circuits that could be modified for use as a guitar amplifier.
If you were interested in designing an amp around these, and willing to share your design with me.
I'd be more than happy to ship you these tubes.
I have two more pairs of these for myself, and will likely not be able to design a circuit for them any time soon.
They seem like really high quality tubes that could be made into a nice amp, by a more knowledgeable person.
If you are interested, just PM me your address and I'll ship you a pair asap. :l2:
-
Interesting tube, I've seen a bit NOS for sale the last year at the Hamfest in Friedrichshafen (€ 25 for one)
Franco
-
Actually, the only audio circuit I could find using that tube was from a guy in Germany. :l2:
-
for E130L amp OT.
https://www.edcorusa.com/cxpp100-ms-1_7k (https://www.edcorusa.com/cxpp100-ms-1_7k)
for the PT - hammond p/n 185G230
for the filaments - hammond p/n 266PA6
--pete
-
Pete,
I really appreciate what you have done for me there! :worthy1:
I actually finally see how you used the data sheet to put that together.
That helps a lot.
If you want to claim those Mullard tubes, PM me with your address.
I will happily ship them to you for this work you have done. :icon_biggrin:
Basically, you have completed the Output section and PS.
So now it could be as simple for me as to just steal Tubenit's
pre-amp and PI section of the HoSo and paste it together.
A complete E130L guitar amp would result?
Or are there still calculations and adjustments for a proper driving signal needed?
I think the PT from the pulse Generator would work for this design.
3 separate 6.3 VAC taps on it, for plenty of heater current.
I'd only need to purchase that monster OT.
I could offer one of those PT's to be shipped freely to you for continued guidance on this design.
You too would probably only need an OT then to complete this amp.
You might even have an OT already that would work.
I definitely do not have an OT anything like that in stock.
It is rather different from most with it's 1.7K plate load.
Again, I truly appreciate your efforts! :worthy1:
Thank you!
Paul
-
thanks, but no need to ship parts. respectfully, any assistance given needs no reward - am happy to help as time permits.
corrected plan --> left off a couple of very important resistors...
--pete
-
Paul,
This gives you a start in using your tubes in an amp design. With Pete's info and this info ............ I don't see any reason why you can't build an amp with this tube. I attached SCH files also for any edits you may want to make.
Study the schematic and layout carefully BEFORE asking questions. See if you can figure this out on your own first. :thumbsup:
IF you find a discrepancy between the schematic and layout ............... go with the schematic. CHECK for ERRORS!
With respect, Tubenit
-
Paul,
Let me give you an example of something I'd want to see you wrestle with alone before asking questions.
DL's B+ rail has 4 nodes. The schematic I drew has a node E. How would you modify DL's B+ rail to have a node E & can you label his B+ rail with nodes A thru E?
IF you have a question about something ........... post what you think the answer is when you post the question.
The other thing is Pete was gracious enough to name specific PT and OT's that he recommended. There is a reason for that. Pete is one of the most knowledgeable and generous contributors to the forum. IF you are not going to use what he suggested, please look up the specs on the PT and OT he recommended and make certain that what you are substituting will work.
With respect, Tubenit
-
OK, so on DL's PS you say it has 4 nodes.
I would say there are 3 nodes and a neg bias voltage.
Not to try to correct you or anything like that,
just to illustrate how I use those terms, which is probably wrong.
So, on DL's PS I would label them as such:
A = 320Vdc
B = 280Vdc
C = 160Vdc
and negative bias voltage call it
D = -17Vdc
I did think about this design and how to modify it.
But I also thought about how I might be able to use the PT and chokes I have.
So, here are a couple of pictures of those parts.
Then I tried to think about the limitations of these parts,
and how I could use them to meet the needs of this circuit's design.
The data sheet seems to indicate to me that these E130L tubes use a lot of current.
My PT has limits on it's primary HV tap that seem to fall short of the current requirements for the output tubes and the pre-amp tubes combined.
It might even fall short of meeting the current requirements of just these output tubes. :dontknow:
-
So with what I have I tried to design a PS that would meet the specs you gave me.
My 1st try was this.
Then I thought about how I could possibly use the other HV tap to provide lower voltages with a separate current source.
So I made a 2nd .psu file with my 2nd HV tap and another 200mA of current.
I'll try not to ask a bunch of silly questions right away. :laugh:
What do you think of what I have done so far?
I'm also just learning that PS program, so I did what I could to design PS circuits that might meet the demands of this circuit.
If I can separate the PS into 2 parts I think I can better provide what the circuit needs.
I could redo PS v1 just to supply the plate and grid voltages. If that is the best way.
I'm not sure there is enough current from this PT to do that.
So I could also redo PS v1 to just supply the Output tubes their B+.
And then redo PS v2 to meet the requirements of the pre-amp,
and the Output tubes grid voltage of 150V.
Or am I way out in Left field now? :w2:
-
It didn't want to take my .psu files, but I have them available to modify as directed. :icon_biggrin:
Oh, and that Edcor OT DL listed looks very nice. :worthy1:
But would this one also meet my needs for $20+ less.
https://www.tubesandmore.com/products/P-TM0100 (https://www.tubesandmore.com/products/P-TM0100) :w2:
-
first of all, this power stage needs only 9Vrms to deliver 60W of power so tuning the LTPI driver is going to take some experimenting.
these power tubes are like 8417 on steroids. the internal elements will be in very close proximity so the tubes might not survive road-trips or fare well in a combo. i would not use them in a guitar amp. add three 12BH7s and you have a nice 60WPC hi-fi amp. that said, read on if you wish...
i'm not even going to try and design around those HP PT. IMO they won't work well for this application.
http://catalog.triadmagnetics.com/item/power-transformers/-connect-world-series-power-transformers-1/vps230-760-1 (http://catalog.triadmagnetics.com/item/power-transformers/-connect-world-series-power-transformers-1/vps230-760-1)
55 bux at mouser for the PT and filament transformers.
for the power node correlation:
A=320V - OT CT : power tubes plate power.
B=160V - power tubes screens.
C=280V - LTPI - or whatever type of phase inverter you decide to use.
Bias = -17V.
D=2xxV - ADD a series RC network (10k/22uF) to node C.
E= 2yyV - ADD a 2nd series RC network (10k/22uF) to node D.
100W 1.7k marshall OT should work.
--pete
-
first of all, this power stage needs only 9Vrms to deliver 60W of power so tuning the LTPI driver is going to take some experimenting.
i'm not even going to try and design around those HP PT. IMO they won't work well for this application.
http://catalog.triadmagnetics.com/item/power-transformers/-connect-world-series-power-transformers-1/vps230-760-1 (http://catalog.triadmagnetics.com/item/power-transformers/-connect-world-series-power-transformers-1/vps230-760-1)
100W 1.7k marshall OT should work.
--pete
I was kind of thinking the same thing after looking at the AB PP specs.
I thought since it was the PT it used as a pulse generator,
I might be able to reuse it, but it does look doubtful now, IMO.
Thanks for all the help guys!
I really appreciate it!
If and when I do build this I was planning to use the pulse gen's rack mounting case.
Lots of room in there to keep things spaced properly.
But if the PT is a NO-GO, and I'm guessing that it is, then the case is less appealing.
I actually thought the rigorous shock and vibration test requirements,
would make these tubes less susceptible to moving shock issues. :dontknow:
That just shows how little I understand the bigger picture. :laugh:
-
Is the full 760mA of current needed or would the slightly smaller 570mA version suffice?
http://www.mouser.com/ds/2/410/VPS230-570-781478.pdf (http://www.mouser.com/ds/2/410/VPS230-570-781478.pdf)
Are 2 of these at 4A each:
http://www.mouser.com/ProductDetail/Hammond-Manufacturing/166N6/ (http://www.mouser.com/ProductDetail/Hammond-Manufacturing/166N6/)
Using 1 for the output tubes (1.7A x 2 = 3.4A),
and another for the other tubes (I didn't spec all these tubes yet, but expect 4A would suffice).
Better than 1 of these at 6A's ? :dontknow:
http://www.mouser.com/ProductDetail/Hammond-Manufacturing/166Q6/ (http://www.mouser.com/ProductDetail/Hammond-Manufacturing/166Q6/)
This one would leave me less than 2.6A for the other tube's heaters.
-
marshall 100W OT: 100W/450V so ~0.22A 1/2 primary. your 60W E130L 60W/300V so ~0.2A - should be fine just a bigger/heavier chunk of unneeded metal to haul around.
filaments:
5879 = 0.15A
12AX7 = 0.3A x 3 = 0.9A
El30L = 1.7A x 2 = 3.4A
3.4+0.9+0.15=4.45A
4A will probably work, but likely sag below 6V and run hot. use the 6A part - 5 bux won't break the bank: maybe you spend more than that on beer & ebay junk? :icon_biggrin:
--pete
-
Good,
I just ran the numbers and came up with total HV draw 445mA.
My numbers matched yours, thanks!
So the HV PT with 570mA should be OK? :dontknow:
Or is the bigger heavier 760mA PT needed?
I didn't add 200mAs for the OT, was I supposed to?
If I was, that brings the HV PT up to 650mA draw and that would require the 760mA PT.
Heater draw of 4.45 A
I was planning on buying 2 of the 4 A heater transformers
instead of just 1 - 6 A heater transformer.
2 of the 4A transformers are actually cheaper than 1 6A transformer. :l2:
Do you prefer the Edcor OT, Pete?
I thought the Marshall was lighter than the Edcor.
Edcor OT said only made to order, where the Marshall OT was In Stock ready to ship.
If I drank a lot it would cut into my Ebay funds. :l2:
My wife says I have an Ebay addiction, she may be right. :icon_biggrin:
Tube amp junk I buy is cheaper than Guitars though. :l2:
I have more Guitars than I need, but who doesn't need another Axe?
-
When you mentioned the 8417 that was the 1st I had heard of that output tube.
Had to check the Data sheet on it.
It strikes me as this is the tube on steroids. 100W from a PP pair with 2.5% THD?
This one is a Beast. If I'm reading things right it takes a 29V signal to drive it's 100W output.
If that is right, then this takes 300+% more signal to push it's accelerator to the floor.
Is that what you meant about the E130L being an 8417 on steroids?
-
> 100W from a PP pair with 2.5% THD?
6550 does that easy.
8417 is a cheap (hi-fi grade) 6550 carcass with G1 set too close so it needs smaller drive signal (and does fail more).