Increasing Filter cap values

[pbman1953]

After talking with Ed, I want to possibly increase filter values for my Traynor.


It's running out of power compared to my Fender 300T. I know, and Ed has explained that the Traynor is not a 300 watt amp. But I've run my Fender with 4 -6550's compared to 6 and still it kicks but as far as sustain and attack.


The Fender does have 3-330uf's / 450 volt. In my amp now I have a 100uf going in series like the schematic into an F&T multi cap 40 +40/ 450v. I've seen a F&T Multi with  100 + 100. My question is why is the single 100 in series (with the 40+40)  and not parallel with the others to get a higher total? This design is done twice side by side in the schematic

[SoundmasterG]

Power output is determined by the B+ voltage, the power tubes used, and the output impedance and how well that matches what the tubes want to see. So breaking that down further, your power supply which includes the power transformer, the filter caps, type of diodes (tube or solid state). Four 6550's will put out more power on the same voltage than four EL34's any day of the week, so you are comparing apples to oranges. Going with larger caps in the power supply will allow that amp to reproduce bass frequencies quicker, so the bass will sound tighter and a bit more present, but it won't give you any more power out of the amp. Use more efficient speakers or more speakers if you want more volume.


Traynor did their filtering in a strange way with one 80uf 450v cap in series with two 40uf 450v caps in several places in the amp. For identical caps in series ,the caps halve in value but double in voltage. Caps in parallel with identical values double in value and stay at the same voltage. So what they end up with there is essentially a 40uF 900 V cap, which I assuming they did because they wanted a higher voltage capability at that node, but they could have done it cheaper than they did. ((Two 40uF 450v in parallel = one 80uF 450v cap; one 80uF 450v cap in series with one 80uF 450V (two 40uF 450V in parallel)= one 40uF 900V cap)


Anyway, in summary, getting more power means a higher B+ voltage aka a different power transformer, changing the output transformer to one with a different impedance that matches the power tubes better (possible but not likely since the manufacturers usually designed for the proper load for max power), changing to an output transformer that is designed better with better frequency response and better metals used in its construction, (unlikely since Traynor used Hammond transformers which are excellent quality), or redesigning to use larger power tubes that put out more power such as the 6550/KT88. As you can see all of these approaches cost a lot and are a lot of trouble. It would be easier to sell it and buy a bigger amp, but you already have those....so just enjoy the tone you are getting and live with the lesser power.


Greg

[pbman1953]

Greg


This amp has 4-kt120 tubes running and a new Heyboer amp that is set up for 4 or 8 ohm operation.


So having higher capacitance, say 250uf at 450volt is not better than 40uf at 900volt. In my car audio days we loaded a high-end system with one 1farad cap at 20 volts dc. The systems total benefited and the bass was so much cleaner and tighter.

[sluckey]

My question is why is the single 100 in series (with the 40+40)  and not parallel with the others to get a higher total?

Your B+ voltage is 540V but the filter caps are only rated for 450V. So the caps are put in series to increase the voltage rating so they can operate with 540V applied. With this series arrangement each cap will only see 270V.

You can increase the cap value as much as you want but you will have to increase the value of all three caps. For example, right now using the 80µF and 2x40µF can gives a total of 40µF for the first filter. To increase to 50µF total you would need a 100µF and 2x50µF can.

[pbman1953]

I should of mentioned that I do have one 100 and a 50 + 50 multi per section, all rated at 500.


I've found a F&T multi with 100 + 100 at 500v plus a JJ
250 at 500v

[PRR]

> running out of power compared to my Fender 300T

The Fender 300 is beyond any other guitar-amp. Perhaps inspired by the SVT but significantly more robust. What other amp uses a 6V6 as driver??

>> I do have ..., all rated at 500.

> Your B+ voltage is 540V

500V caps will work at 540V, for minutes or maybe days. Then they BLOW UP. Sure to die at a bad time.

You want to stack 350V caps to about a "700V" nominal rating.

That multi-multi-section scheme was just cheap in the day. It is NOT a good design.

Today we would use "snap caps". Yes, BUY caps; you can't beef-up an amp this large with spare parts. Drill some insulating board (Doug sells it) and stick the caps in, connect the legs.


40uFd (80u + 40u||40u) total on an amp of this Voltage versus Current is just Pete being commercially cheap. From a clean sheet, I would aim for 100uFd to 400uFd. 470uFd 350V is a standard size single cap. Two stacked is 235uFd (6X more than stock) with ample voltage (blow-up) rating. You need another such pair for screen grids. Four 100K 2W resistors to bleed/equalize. Your 500V caps can go at the C29 C32 positions. (They run at 355V or less, but at turn-on they rise toward 500V.)

[sluckey]

Or if you rather work with axial caps you can get four 220µF @ 350V for $20.

[pbman1953]

I like that design and I took  out the old can caps . I'll have to put 2 on top and 2 inside.


On C 29 & 32, I have 2- 100's at 450 volt, is it worth it?


I have a 80 /500 on 29 and a 10/500 on 32, now




Also, If I use the 50+50 (I have now) as a 100 for c29, would it matter if the 100K resistor is still across it, or should I remove it?


Thanks

[sluckey]

On C 29 & 32, I have 2- 100's at 450 volt, is it worth it?

Not likely to help with the "running out of power compared to my Fender 300T" issue. Increasing the size of C26, C27, C28, and C30 should stiffen up the power amp a lot.

Running KT120s is not gonna boost the power unless you put a bigger PT in it also.

Just for general knowledge... When you connect two caps in series the total capacitance will ALWAYS be less than the value of the smaller cap. The formula for total capacitance is the reciprocal of the sum of the reciprocals.

[pbman1953]

Interesting you say stiffen, in the car audio world the big 1 farad caps are call stiffening caps.

[PRR]

> in the car audio world the big 1 farad caps are call stiffening caps.

Which would be used with amps of somewhat more power than the YBA. But let's go with this.

The supply voltage ratio, 540V to 12V, is 45:1.

For the same power, the YBA's current must be about 1/45 of the car-amp's current.

45X45= 2,000.

If a 1F cap is good for the 12V car-amp, a 1/2,000F or 500uFd cap would be good for the 540V YBA3.

Actually the 1F cap is used with more-Watts amps than a YBA3. (YBA ~~ 180 W, big car amp >1,000W.) That's why we are steering somewhat lower than 500uFd. Say "about 200-300uFd".

The cap MUST stand 540V (plus safety margin). Electrolytic caps go to 450V, sometimes 500V. The oxide can't be made thicker. So we need to stack caps. Two caps series is twice the voltage and half the uFd. So we need at-least 270V caps (300V is marginal, use 350V) of about 400-600uFd each. 470uFd 350V is a common size. Makes 235uFd at nominal 700V.

I do not know why the screen-node caps are as large as the main caps. I suspect they could be less than half the size of the mains. 100uFd-150uFd. The voltage stress is about the same, 535V. So pencil two more 350V caps but at 200ufd-300uFd each. 220uFd 350V is a common size. Makes 110uFd 700V.

Or since caps are cheaper by the dozen, six 220uFd 350V or a full 10-pack of 150uFd 350V. Use six series/parallel for 225u 700V, four series/parallel for 150uFd 700V.

I once upgraded several Bogen 300W amps with bunches of caps, about like this. Made a difference. Just 360W but much smoother at full roar.

[jjasilli]

https://www.parts-express.com/resources-stiffening-capacitors-faqs

[pbman1953]

That's them. I had 2 caps in my car . They made a huge difference as far as attack and sustain.


In the mid 90's I bought the 1 Farad caps from Sprague and sold them to Car Audio companies like Parts Express and Amp maker Phoenix Gold. Sales were hot because it was new and highly recommended by the gurus of car audio at that time Richard Clarke. Rochard's Grand Nation is a story alone iof itself. One of a kind and here's the article about his car.


http://www.mobilesoundscience.com/showthread.php/447-Richard-Clark-1986-Grand-National-1992-CA-amp-E




My only competition was a company called Lighting Audio. He bought his from Phillips. Sprague was considered the gold standard as far as the big caps. Lighting convinced Philips to change the traditional outside wrap to show graphics of the the company that bought them. Sprague was very hard nosed not to do that because they felt that the wrap could not be played with because of its job to contain it in the event of a a blow up. Lighting seized that opportunity and was so successful that Sprague sales decreased. By that time thre amp maker made thier own deals with overseas vendors. I moved  and lightning sold to Rockford Fosgate.

[pbman1953]

Sorry to be a paid about this question, possibly it was overlooked.


Also, If I use the 50+50 (I have now) as a 100 for c29, would it matter if the 100K resistor is still across it, or should I remove it?




The schematic doesn't have a resistor across it.

[sluckey]

I would wire it like the schematic.

[pbman1953]

Ok, thanks, back to work I am.

[pbman1953]

Any suggestions where to get the caps?




I'd prefer one with the ringed terminal  instead of a straight terminal


Thanks



 

[sluckey]

Click the capacitor link at the bottom of this page.

[pbman1953]

I did but I didn't see the style and value size I want,


Antique doesn't have it . Weber is too difficult to look up. Mouser is also hard to look up unless you know every bitty detail.


The 470uf/350 doesn't seem to be as common. Plus inside I can't go too long. The 2" height works and I have to put the side ways. Outside I'm fine with most heights. The old can caps were 2 1/2" high.

[sluckey]

I doubt you will find a 470µF/350V cap at any of the guitar tube amp suppliers. IMO 470µF is excessive for any tube amp. 220µF is common and all the suppliers you named have those.

Mouser has several 470µF/350vdc caps to choose from. You don't need to know "every bitty detail". All you need is the value and voltage rating. Learn how to use their filters. It's really easy. Ignore the filters if you don't know what they mean but you must use the value and voltage rating unless you want to scroll through hundreds of pages of caps. It took me about 2 minutes to find several 'snap-in' style 470µF/350V caps.

[DummyLoad]

another source.

http://www.arselectronics.com/ARSWEB/CapPage2.html


--pete

[DummyLoad]

http://www.mouser.com/ProductDetail/Nichicon/LGN2V471MELC30/?qs=sGAEpiMZZMvwFf0viD3Y3RXRUVU1xXQD5rn7hNYrnMY%3d


http://www.mouser.com/ProductDetail/Nichicon/LNT2V471MSEC/?qs=sGAEpiMZZMvwFf0viD3Y3RXRUVU1xXQDO31KBdyuATk%3d


--pete

[DummyLoad]

cap clamps for the 35mm dia parts. 


http://www.mouser.com/ds/2/88/hardware-20153.pdf
http://www.mouser.com/ProductDetail/Cornell-Dubilier-CDE/TH25/?qs=sGAEpiMZZMsYDbxkXDKK1omjIvfDQx%252b%2fkzIXVTnNKFs%3d


--pete

[sluckey]

Neither of those Nichicons are in stock, but several others are.

[DummyLoad]

http://www.mouser.com/ProductDetail/United-Chemi-Con/EKMQ351VSN471MA30S/?qs=sGAEpiMZZMvwFf0viD3Y3Wd4FpOoUsJZj2DkBmbVyFM%3d


copied wrong window.


the screw term cans are due in next month.


--pete

[DummyLoad]

if it were mine: for c26, c27a+b, c30, c28a+b id use 4 of the parts in this link


for C29 one of these in this link.


with 3 of the horizontal cap mounts from the mouser link above - the TH-25 clamp for horizontal mounting 1.375" dia. parts c26, c30, c29.


--pete

[pbman1953]

"if it were mine: for c26, c27a+b, c30, c28a+b id use 4 of the parts in this link "




I don't think I have room for that. As is I had to remove the 2 topside can caps. I'm figuring 2 outside and 2 inside.

[DummyLoad]

"if it were mine: for c26, c27a+b, c30, c28a+b id use 4 of the parts in this link "

I don't think I have room for that. As is I had to remove the 2 topside can caps. I'm figuring 2 outside and 2 inside.

looking at some chassis pics posted by others looks like they will. measure. 

 
--pete

[Ed_Chambley]

Ah yes, never quite satisfied.  I know the feeling well.  Went to 2 shows this weekend.  90's Country/Rock is the best way to describe.  Little Texas and Sawyer Brown.  Both did a great job, but I have a preference.  Little Texas hit the stage with no backline, just instruments and drums.  They did a great show and everyone at the place was having a good time.  Music sounded very much like the recordings as things seems to be today.


Sawyer Brown, different story.  Little older gents, few more hit songs and more stagehands.  Full backline with a Fender Twin, Ampeg SVT, a Blue one with 8, 10's, Lead Player Metro Plexi 4 holes 100 watts and drums behind Plexiglass.


My point, not a damn thing.


Seriously, Sawyer Brown sounded live and alive.  Not to take away from anyone as we all are playing the way we are required today and I have even looked at a couple of things like the Headrush pedalboard and the molding or profiling like the Kemper.


Yes, I hear it too and it is a problem for me so I do as you.  Keep tweaking what was perfect last week.  I happen to own a 72 SVT and I will say it is one fine sounding amp, but it does not have the sheer girth of the Fender 300 and in the tube world it is rare.  They call it a 300, but it is more than that.


The Traynor amps are fun to have around and you can do about anything you want to with them.  The basis is great and one of the few handwired amps that have not skyrocketed, these and a few Laney's, but even theses are getting expensive.


Give it a try on upping the main filters.  You will notice a difference.  Just like all the things you have done to the amp, all of it has made a little difference and all the little differences obviously you are liking.


Just keep in mind your voltages and have fun.  There is always a way to add more.  Can you say Big Doghouse.

[pbman1953]

Just to report back that I've ordered-


4-  JJ-  550UF @ 385 Volt


4-  220K- 3 watt- resistors


I'm pretty psyched to get this done.

[pbman1953]

Forgot to ask If after the install  if I have to rebias?


Thanks

[shooter]

Forgot to ask

If it were me, I'd recheck all my power rail taps and bias, just because I changed things

[pbman1953]

I'm not sure what happened but it's blowing fuses. I tried to be very careful.


No smells , no noise. It was instant. The Light came on them off.

[Tony Bones]

Does the fuse blow the instant you flip the switch? It's possible you wired everything correctly but the inrush current filling up all that capacitance is too much. If it's a fast-blow fuse then you can try slow blow. Or add a NTC thermistor, either in the secondary or the primary leads of the PT.

Or put a big power resistor in series with the ground leg of the rectifier with a switch that shorts the resistor. You power up the amp with the switch open letting the resistor limit current then flip the switch after a few seconds. Maybe 1kohm @ 10 watts? Just guessing what might work.

[pbman1953]

To be sure I flip the amp and vacuumed it. I tried other fuse but under value to be safe. I disconnected the new stuff and still they blew. I'm out of value fuses. All I have are ceramic 10 amps.  I tried a 7 amp clear with metal center and it blew. I'll have to get more 5 amp tomorrow.

[sluckey]

Maybe you have a wiring error? Maybe that amp doesn't like 550µF caps?

[Ed_Chambley]

Post photos of how you have it wired. Put it on a bulb limiter, 100 watt at least. It should hold a 5 amp fuse, so you have an issue.


I want to see each cap, where it is connected and what it connects to. I believe you may have grouded your series caps. I say this because you are not mentionong a blown cap.


Do not put another fuse in and power up. Photos from diodes to caps.

[pbman1953]

ED


I'm not sure what you mean about the bulb limited.


Here are the pics but I'll have to repost due to the amount of pictures

[pbman1953]

next batch

[pbman1953]

Would it be possible, and without harm, to remove all the those caps, off the connections ,  just to see if the lights turn back on?

[sluckey]

Much easier to just disconnect that green cloth covered wire from those green diodes. Then compare the schematic to your actual wiring to determine the wiring error.

[pbman1953]

Hmm, I removed the wire at the diodes and it still blew.




Possibly my PT?

[sluckey]

Possibly, but I'd first suspect shorted diodes. Disconnect the two red PT wires from the green diodes. Fuse hold now?

[pbman1953]

You nailed it!


Lights and fan only

[sluckey]

So, you need to replace all 6 of the diodes. But even more important... Find the wiring error that killed the diodes. Your pics are good quality but we really need to see pics that show how all of your new filter caps are connected together, ie, show all caps in one pic so we can trace wiring.

[pbman1953]

I was lucky and just got back from an electrical house that had NTE 1N4007 diiodes-




1 Amp @1000 volts


I install all new 7, even the bias location. I figured why not.


I turned the amp on, minus the green wire cap feed, and all's good.




2 out if the 7 diodes were bad.


Here are more pictures

[pbman1953]

Is it possible the that diodes failed because they couldn't handle the new parts?


For the most part I think the wiring is correct.

[sluckey]

Is it possible the that diodes failed because they couldn't handle the new parts?

Yes. Those huge filter caps you are using will demand a huge initial charging current through the diodes. And if that is the case, your 1N4007s are at risk of the same failure. Those green bullet diodes are rated at 1A just like the 1N4007s. I would replace those 1N4007s with 1N5408s that are rated 1000v/3A. Less than 40 cents each.

It's also possible that the huge initial charging current will strain the PT to the point that it fails.

So, plug it in and measure the B+ voltage. What have you?

[pbman1953]

I could of gone with the 3a but I wasn't sure if they were overkill or not. I can get those too. Hopefully for now the 1A will get me by. The guys at the store said that ones he gave me were 1 Amp but at 1000v. The PH204's in the amp were 600V


On the B+ , I wasn't sure if you wanted AC or DC, so I measured both




DC- 710


AC-293

[sluckey]

DC-710! That's considerably higher than the 540V shown on the schematic. Did you have the power tubes plugged in? Where did you measure AC-293?

Does the amp now sound like you wanted it to sound? Not running out of power?