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#26 2008-05-15 16:11:43

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Hey Paul and Steve,

Hopefully this will clear things up, we rechecked the voltages (and this time wrote them down):
117ACV input on primary side
374ACV on secondary (measured between two red leads) at no load (disconnected from circuit).
66ACV one red lead to gnd.
189ACV 2nd red lead to gnd.
6.1ACV measured between two green wires from transformer under load, not disconnected from circuit.

Tonedef

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#27 2008-05-16 01:17:39

paully
Member
From: Northern New Jersey
Registered: 2007-11-02
Posts: 200

Re: V-4 Overheated then Quit, Any Ideas?

big_smile big_smile big_smile LOL. Yep, needs a new PT!!

If the new one is physically identical, you might consider swapping the old transformer's metal covers onto the new one. That'll preserve the 'original' look, and you'll have the new guts inside.

Best, Paul


WADAYAKNOW.. For the first time in my life, I'm wrong again!

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#28 2008-05-16 01:25:06

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Good idea, thanks Paul.  Fliptops is sending me a dual voltage tranny, as they are out of the one I need, so I'm betting the cover might not fit.  Should I screw around with trying to make this amp dual voltage, or just leave things alone, do ya think?

Tonedef

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#29 2008-05-16 02:55:26

paully
Member
From: Northern New Jersey
Registered: 2007-11-02
Posts: 200

Re: V-4 Overheated then Quit, Any Ideas?

Dunno. Are you planning to play Europe this year, and will you be using this amp big_smile ? Personally, I'd set it up for 117 VAC and tie off any other leads. But then again you do have lots of neat tools and test equipment, so maybe.. smile

Have fun.

Best, Paul


WADAYAKNOW.. For the first time in my life, I'm wrong again!

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#30 2008-05-16 03:13:10

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Thanks Paul, I thought you might have some double secret trick as to how I can really make use of this super spiffy PT! 

I also wanted to ask you your opinion on this, if it is a dumb question (and I shoulda known) I apologize in advance!  Was it just the PT's time to go, or did the Sovtek 6L6GB's the previous owner thought would be a great idea to use hasten the PT's demise in any way?

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#31 2008-05-16 14:43:57

paully
Member
From: Northern New Jersey
Registered: 2007-11-02
Posts: 200

Re: V-4 Overheated then Quit, Any Ideas?

tonedef wrote:

Thanks Paul, I thought you might have some double secret trick as to how I can really make use of this super spiffy PT! 

Was it just the PT's time to go, or did the Sovtek 6L6GB's...

>>>>>>>>>>>>>>>>>>>>
The only super-(duper) spiffy thing I can come up with is when tying off the unused primary wires, if that's what it uses as opposed to lugs, I'd tie all of them to an externally accessible, panel mount rotary switch. Leave the switch normalled for 117 VAC. Then If you do need a different primary voltage, it's as easy as turning the dial.

The byproduct of transformers is heat. They all create some, and it's usually why they fail. Over time, the lacquor insulation on the windings came break down, and turns can short together. This could account for the reduced voltages you're reading.

Power surges or continuously high line voltage doesn't help either. Line conditioners are a good idea in front of any piece of electronic equipment. I use Tripplite stuff http://tripplite.com/products/conditioners/index.cfm .

One other thing. If you're handy with tools, pull the rear panel on the V4's case, make a duplicate from plywood, cut a hole in it and install a small fan. In my book, THAT'S protection.

Things like fuses, diodes and current limiting resistors in the PS help protect the PT from overload, but it's just a matter of time. If the amp is properly biased(your responsibilty if you mixing and matching non-spec tubes) for the power tubes of choice, you really shouldn't worry about them as candidates. They wouldn't be in business long if they consistantly turned out faulty tubes.

Best, Paul


WADAYAKNOW.. For the first time in my life, I'm wrong again!

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#32 2008-05-16 15:59:14

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Thanks Paul, for your advice, as always.

Tonedef

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#33 2008-05-18 23:29:55

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Newest update, and it isn't good.   We just finished another frustrating afternoon spinning our wheels on this amp.  This new transformer can't be right, or was not wired right from the factory, or the wiring instructions from Fliptops are wrong, as I am still short over 100 volts. 

Due to all the problems we've had, we checked the voltages on the new transformer prior to installing it into the circuit.   The secondary voltage is 420ACV with direct 119ACV input, 400 at 117V using a variac.  I did get the 6.3ACV on the other side.  We connected the wiring as per the Fliptops instructions for their dual voltage PT.  Before we even try to connect this into the board, what is acceptable secondary voltage at no load?  What should we get from one red wire to the transformer case?  I'm assuming each side should be the same to combine for 500-plus volts?

I hope there is a simple answer for the low PT voltage, as I am really unhappy right now.

Tonedef

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#34 2008-05-19 00:12:12

paully
Member
From: Northern New Jersey
Registered: 2007-11-02
Posts: 200

Re: V-4 Overheated then Quit, Any Ideas?

That might be right. Go ahead and connect the seondaries and bring it up slowly with the variac. Unless there's something else wrong with the amp, it won't hurt the transformer or the amp. Just be triple sure about the primary side. Find out what make/model # it is and I'll see if I can locate the specs.

Pull up this schemo http://www.drtube.com/schematics/ampeg/vt22-v4-74.gif and compare it's color-coding with the transformer's primary wires.

My current amp build calls for B+ of 400 VDC, but the original transformer is rated at 350 VAC on the secondary side. I don't recall what the V4 sec AC is, and no longer have one to test. Maybe someone else has one opened up.

Best, Paul

Last edited by paully (2008-05-19 00:22:37)


WADAYAKNOW.. For the first time in my life, I'm wrong again!

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#35 2008-05-19 00:38:42

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Thanks Paul.  Bruce from FT's told me I should be getting 500VAC, plus or minus at 10mA right before I bought this new PT from him.  The schematic calls for 540 V at the connection on the board from the PT if I'm reading it right.  I hope you are correct about 400V's being right, that would be nice.

Steve believes the PT to be made by Heyboer.  There are no markings whatsoever on it.  It is this one: 

www.fliptops.net/catalog/product_info.p … cts_id=635

Tonedef

Last edited by tonedef (2008-05-19 00:42:36)

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#36 2008-05-19 01:43:54

hangman
Banned
From: Seattle Washington
Registered: 2006-09-04
Posts: 1848

Re: V-4 Overheated then Quit, Any Ideas?

Tonedef.... the secondary AC voltage should be very high.  in order to get that 540 volts DC the AC voltage should be over 1000volts AC across the two red leads of the secondary.   my guess is more like 1100-1150 unloaded.     

does the heyboer have dual primaries? 

are you sure your VOM is functioning correctly?  it would seem strange to me that a brand new transformer would be defective.

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#37 2008-05-19 03:38:17

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Thanks Steve, maybe we are doing something really wrong, I'm at a loss.  We are getting 400VAC +/- across the two red leads together, much less the numbers you are looking for.  The VOM is a Beckman, every known voltage we have checked with it has been right.  I do not know if this PT has dual primaries or not.

If I hadn't previously bought brand new components that were defective I'd certainly agree with you about the PT.  That is why we checked it before soldering it in, I don't trust anything "new" anymore.  "New" doesn't always mean it works, not like in the old days, anyway.  Maybe the wiring instructions are wrong.  I didn't want this dual voltage PT but that's all they had.  Other than double checking the validity of the VOM, what am I missing here?  I guess what I really need are the specs for the secondary voltage on this PT.  I'm about ready to give up and drive this big paperweight up to you!

Tonedef

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#38 2008-05-19 13:55:01

paully
Member
From: Northern New Jersey
Registered: 2007-11-02
Posts: 200

Re: V-4 Overheated then Quit, Any Ideas?

tonedef wrote:

I do not know if this PT has dual primaries or not.

>>>>>>>>>>>>>>>>>
Call Heyboer direct for the right info http://www.heyboertransformers.com/index.shtml or Ampeg http://www.ampeg.com/contact.html .

You've ID'd the secondary wires(R-400, GR+ct-6.3). How many wires are left, and what color are they? Also, if you get time physically measure the transformer(HxWxD). The right transformer shouldn't be that hard to locate. Hammond has 'Classic' replacements about half the price of Fliptops. Just a matter of knowing the diminsions and the right sec AC voltage and the VA rating. 

Best, Paul


WADAYAKNOW.. For the first time in my life, I'm wrong again!

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#39 2008-05-19 16:06:36

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Paul and Steve,

I just got off the phone with Heyboer.  They said I should be getting 400 to 420 VAC from the secondary, which will give me 540VDC.  My PT is up to spec, excellent news!  I guess I must be missing how the rectifier is turning 400+ VAC into the 540DC voltage. 

Tonedef

Last edited by tonedef (2008-05-19 16:28:36)

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#40 2008-05-19 18:51:50

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Good news!  We got the new PT hooked up, ran voltage checks and all the voltages are checking out on the plus side!  What a relief.  And this new Heyboer PT is running much cooler than the original was before it went to the great scrap yard in the sky.  I am really looking forward to getting this hooked up and playing thru it tomorrow.

Tonedef

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#41 2008-05-19 19:46:39

paully
Member
From: Northern New Jersey
Registered: 2007-11-02
Posts: 200

Re: V-4 Overheated then Quit, Any Ideas?

Glad to hear that. Don't throw the original out. It's reading(375 VAC?) is not that far off. Now, go make music wink big_smile !

Best, Paul


WADAYAKNOW.. For the first time in my life, I'm wrong again!

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#42 2008-05-19 19:57:40

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Hi Paul,

I'll keep it for sure, but that had to have been the problem.  That 375VAC is with no load on a good day.  I can imagine it went downhill quickly from there with any kind of load on it.  On the other hand, with this new PT hooked into the system, the readings actually increase slightly after it ran-in a little--my kind of deal!

I'll report in after I get this hooked into a cab tomorrow.

Tonedef

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#43 2008-05-19 20:50:23

hangman
Banned
From: Seattle Washington
Registered: 2006-09-04
Posts: 1848

Re: V-4 Overheated then Quit, Any Ideas?

Tonedef...

I was mistaken about the voltages you should be measuring.   I was thinking in terms of peak to peak voltage,   not RMS which your meter will measure.   

roughly 390-400 volts RMS is correct. 

sorry again for that mistake.  it had been a long day.

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#44 2008-05-19 21:04:51

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Glad to hear that, Steve, I was really wondering what the heck was going on yesterday with everything amp related!  My brother figured you made a mistake, tho, so no worries.  I am looking forward to get this hooked up now that it is running on all 8 cylinders!

Tonedef

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#45 2008-05-20 22:30:16

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Where is a good source for diodes and resistors?  I'm not happy with a few in the amp, nor the replacements I found locally.  For instance, all I could find to replace the rectifier diodes were general purpose, I'd rather have audio quality diodes.  I would like to upgrade, but some sizes/values in this amp are hard to come by. 

Thanks,

tonedef

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#46 2008-05-21 00:44:16

paully
Member
From: Northern New Jersey
Registered: 2007-11-02
Posts: 200

Re: V-4 Overheated then Quit, Any Ideas?

If you can navigate their site, Mouser is about the best electronics source that I've found. Not sure what an 'audio quality diode' is, but if you're talking about signal diodes, that's not a proper replacement. Not sure why you want to change out the diodes(it won't improve the sound), but a larger power rating is recommended if you do. I use 3-5 amp/1000 volt general purpose rectifier diodes for replacements, the reason being if they short out, the sound and smoke ain't pretty. Better to have the fuse let go.

Best, Paul


WADAYAKNOW.. For the first time in my life, I'm wrong again!

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#47 2008-05-21 00:49:44

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Thanks Paul, I'll check them out.  One of the local V4 gurus likes to swap out the rectifier diodes for bigger ones, claims it works better for bass that way.  Who knows, everyone has their theories...

Tonedef

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#48 2008-05-21 01:05:54

paully
Member
From: Northern New Jersey
Registered: 2007-11-02
Posts: 200

Re: V-4 Overheated then Quit, Any Ideas?

Here's a link to the 3 amp diodes:
http://www.mouser.com/Search/Refine.asp … s=P_SField

Something like this will work fine:
http://www.vishay.com/docs/88516/1n5400.pdf

Have fun.

Best, Paul


WADAYAKNOW.. For the first time in my life, I'm wrong again!

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#49 2008-05-21 03:06:44

tonedef
Member
From: So Cal
Registered: 2008-02-12
Posts: 59

Re: V-4 Overheated then Quit, Any Ideas?

Thanks Paul!

Tonedef

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