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Building an Ampeg Heritage

#81
JGR said:
FWIW, the USA made replacements Fliptops sells are Heyboer.
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For the [Invalid or Expired Link Removed] or the ones they sell for the SVT CL? They're two different prices - both much lower than those listed on [Invalid or Expired Link Removed], and the SVT-CL transformers are listed as [Invalid or Expired Link Removed] so wouldn't that be EW, as they were the original equipment manufacturer?
 
#82
Bassoballs said:
The big difference between a stock and the Metro/Heyboer OT is the amount of laminates used in construction. The Heyboer has 2 to 3 times as many laminates. I believe the quality and consistency of the material used is more important than the actual weight. I've never weighed them, but out of curiousity I will.
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I understand what you are saying. I use weight as a general rule of thumb for what I figure the transformer can handle.

Among other things, the type of iron used is important. The original SVT transformers used a relatively soft iron, which was common back then. The plates were fairly thin. Having more iron certainly helps dissipate heat better and helps with the bottom frequencies.

Mercury Magnetics also sells replacement SVT OPTs. No detail are provided other than the price. Some of their upgraded Fatstack and Superstack transformers also use more laminates. They have details on their web site.

Interestingly, the Fliptops B-15 replacement transformers are also made by Heyboer.
 
#84
JimWasHere- it's true. Most of the day I've got my headphones on and my head down in my work- but I really like talking about gear, and don't get me started when I'm onstage with my main band Buttafuko. Some nights the drummer and I spend way more time talking crap than actually playing.
As far as Heritage 8x10 vs. Regular 8x10, the Heritage uses machines screws into T-nuts to secure the speakers, as opposed to wood screws. As Mastermold said, the tolex is more durable on the Norms. I have to be REALLY careful with these things- I move them from an 18" wheeled cart up onto a rolling track to do a sweep test in the anechoic chamber and I've messed up a few cabs in the transition (Sorry! B-Stock!). The results of the sweep test are nearly the same on both cabs. Same deal with the 4x10s.
 
#89
JimWasHere said:
We're musicians, and we care what it looks like! :p
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Damn skippy! I certainly do. Had enough of ugly rigs.

So the power transformer...I just remembered that when I got my B-15N restored, Jess Oliver made a new power transformer for it. He said it was overspec'd compared to the original transformer, but I wouldn't notice a difference in performance. He was right. Don't know if that's typical in all amps, but that's how it was with this one. And I imagine if Stu thought it would improve the amp to change it out, he would have.
 
#90
rodl2005 said:
So you're saying the tolex is more durable on the regular 810's (norms) than on the Heritage?
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Yes the Heritage has soft tolex like the VRs so it scuffs and tears easier than the regular (more plastic feeling) tolex on standard/normal Ampeg cabs. It looks great, just be careful with it. I put a small tear in my Heritage 810 just rolling it out of the music store, caught it on the door. It happens, and will happen the more you use it. So just use it and enjoy how it sounds. But I agree with Jimmy they're also pretty to look at.
 
#93
As Corey said it shouldn't, but it can if the power transformer is underspec'ed.

Power transformers, if pushed too hard can sag, much in the same way as a tube rectifier can. If the circuits attempt to draw more current from the transformer than it is capable of providing, it runs out of gas. This usually manifests itself as a loss of headroom.

If the transformer is spec'ed properly this doesn't happen and the power supplied is stable. On some amps, the sag is a part of the tone and some consider it a desirable feature. Not so much in a bass amp.

In the case of Jimmy's B-15, the original transformer is prone to failure due to overheating. Transformers in vintage amps are particularly prone to failure when overheated. The old insulation on the windings can crack and this can lead to short circuits. Installing a new overspec'ed transformer allows better heat dissipation and, on this amp, is more about insuring long term performance.

More plates in the power transformer would help dissipate heat better and therefore it would perform better. With the extra space available due to the additional plates, it is also possible to use a heavier gauge wire in the windings which will allow a higher current capacity. Again better performance. No chance of being overtaxed, no sag in the supplied power, no loss of headroom.

More plates in the output transformer usually means a better low end frequency response.
 
#94
Regarding power trannies, the VA capability will affect the maximum power output and supply sag under load which translates into the dynamic response and feel of the amp. Unless the tranny is way under spec'd, you wont notice a big change, but the original PTs are probably a bit beefier/better quality which is why you see the old SVTs generally exceeding their output ratings My CL was around 280 watts IIRC.

Bumping up the supply filtering will also impact feel/response, especially at higher levels, making the low end bigger/tighter/cleaner, which may or may not be a good thing depending on what you prefer.
 
#95
MAMMOTHvolume said:
Have you thought about sticking some bigger caps in the svts you do? They normally do the power but look like a 50 year old amp on the scope when they're doing it haha.
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Healthy caps do allow the power supplies to reach the specified voltages. So change those old caps to at least have your amps performing to spec.

I find that the first node in particular in the SVT power supply is underspecified and can be doubled in size. I think that some people wouldn't want the performance of the amp improved because that's the way it has always been.
 
#96
beans-on-toast said:
I find that the first node in particular in the SVT power supply is underspecified and can be doubled in size. I think that some people wouldn't want the performance of the amp improved because that's the way it has always been.
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I totally agree. A lot of guitar amps have more filtering than that.
 
#98
Thanks for all the great info, guys. Awesome! OK, so it wouldn't be prohibitively expensive. That's good. Two trannies would, but one wouldn't be too bad. Mojotone has Heyboers for $350 for one, but if a hundred of us buy one it'll be $308 each ;) Mercurys are like $50 more expensive, and they have a 60's model that's $500.

So what's the difficulty level of installing a new OT? Do you have to be a tech? Never really checked out what's involved. Does drop-in really mean drop-in?
 
#99
JimmyM said:
Thanks for all the great info, guys. Awesome! OK, so it wouldn't be prohibitively expensive. That's good. Two trannies would, but one wouldn't be too bad. Mojotone has Heyboers for $350 for one, but if a hundred of us buy one it'll be $308 each ;) Mercurys are like $50 more expensive, and they have a 60's model that's $500.

So what's the difficulty level of installing a new OT? Do you have to be a tech? Never really checked out what's involved. Does drop-in really mean drop-in?
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Jimmy, I think this is a mod best left to the techs. The power transformer is tied directly to the power supply filter caps (the ones that bite) or vice versa. Unless one knows how to discharge caps safely, he had best stay away. Moreover, you will be dealing with high voltage and current. One wiring mistake can make maximum smoke and a ruined transformer.

jd
 

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