VTL Transformer Up-Grades, Worth It?

I have a pair of VTL 300 Deluxe Mono Block. Is the Signature Output Transformer Upgrade really worth the trouble and the cost? I really love the way they sound but one of the amps is going back for minor repairs and since they are down anyway, I was contemplating having them upgraded. Any comments or advise regarding this issue would be appreciated.

While I haven't heard the VTL Signature upgrade, I can say the the output transformer is one of the most critical items in that type of amp. It is the component that is most prone to compromising the frequency extension, and phase coherence of your music. In general, an improvement in that area is considered a major upgrade, and may also be a major upgrade in price, as good output trannies are not cheap. The push-pull designs such as VTL are not as prone to frequency response problems as are SETs, due to the center tapped layout in push-pull designs, but they will make a big difference. I would give it strong consideration.
much improved bass response. Imo worth it. I'd ask about upgrade to 450 signature status like mine were.
I own MB-185 Signatures, which already come with the upgraded transformers. While I haven't heard the older versions without the Signature tranny, I have heard their current stereo amp offerings, which also lack this feature, and have found them to sound very good in spite of the supposedly "inferior" trannies used. However, I did read a lot of what was written critically about VTL's amps over the years when researching the line, and most reviewers seemed to be unanimous in crediting the upgrade with improved sound at the time it was introduced. Luke Manley certainly promoted the Signatures as being a big step up for his company, but that could always just be marketing. BTW, are you also thinking about getting the coupling cap upgrade? I am considering doing this, since I may send mine back to the factory for other service as well, but I haven't decided yet - it's fairly expensive. (Oh, and make sure to have your B+ fuses and holders uprated to the current-production 600v type while you're at it; the old 250v type is not adequate protection.)
First of all as far as I know that the signature transformer upgrade is not available on all VTL models. It is available only on latest models starting from MB185 or greater. I recently spoke with Bea from VTL on that issue.
Funny this subject came up. I am totally new to tubes, but I ran across a pair fo VTL 225 deluxe mono blocks a few weeks ago that needed repair. I sent them into a local tube shop and it turned out to be a minor issue with a fuse! I thought these would be a nice intro into the world of tubes amps. Since I have a ARC tube pre amp.

I finally got the amps back and dialed in. I hooked them up to my Magnepan 3.6R and talk about Goose bumps. I was listening to a new "used" CD I just got of the "Cowboy Junkies" in Concert and I was floored at the performance of these amps with my power hungry 3.6R. The bass on the Maggies was incredible. The only issue I had was that these mono blocks is the heat the generate. Am I converted? Maybe.

To think it could be improved with a newer power supply is something I need to consider, but for now I an still in aw of their performance.

How much is the upgrade? I guess I should call VTL.

By the way mine have the B+ fuses which I hear is must have for safety.


Marakanetz - I think what you are referring to is the current range of VTL models that are made with this transformer (the Signatures and the References). They do, as far as I know, offer this transformer upgrade to be retrofitted at the factory for certain older models which originally were manufactured with what VTL feels were lesser output transformers. I am not sure off the top of my head which models VTL offers this upgrade on, but I do remember seeing the list on their website.

Jimmy - Just to reiterate, the upgraded transformers we are talking about here are the output transformers, not the power supply transformers, although that may also be a possibility for some of VTL's older models, which as I recall had a reputation for developing power transformer hum until they changed suppliers at a certain point. Also, all the VTL models had B+ fuses, but until recently they weren't high-rated enough to protect the circuitry under all failure circumstances. If you do send yours back to the factory for upgrades, they will also recommend that you have those fuses and holders updated as I described above. BTW, care to tell us what you were using before to drive your Maggie's?
The Transformer upgrade was recommended by VTL. A power switch quit working on one of the amps and I called to get information regarding repairs. Really nice people.
I did have my amps upgraded by VTL. The upgrade’s included the Signature transformers and the addition of B+ fuses. Dealing with Bea Lam was great. She answered all my questions and never sounded condescending like some High End companies. After reading a few of the comments regarding VTL service I was a little worried but the whole experience was enjoyable. Oh ya, the up-grades are worth the money! Many thanks All.
Great! Did you do the coupling caps?
Ya know I didn't think about it. Maybe next year because I won't be sell these amps any time soon.
I had the newer/better output and power transformers installed on my Manley Ref250 monoblocks (2years ago) and also had them install the MIT Multicap coupling capacitors. It was a VERY VERY significant upgrade. I fully enjoyed the amps prior to the upgrade, but after the upgrade the power, bass extension, dynamics, and detail were all very much better. It wasn't as "lushy", but still retained a full harmonically developed sound, something I think these amps did very well. Very much worth it and Evanna Manley is great to deal with!!!

As most are aware, some of the Manley/VTL line are almost identical. In the case of the Ref250 (100+w/ch Triode, 250+w/ch Tetrode), I believe it is basically identical to the MB450, but rather than using 6550's as in the MB450, the Ref250 used EL34's, a lower output tube. I'm sure some parts are different as the Manley Ref250 sold for $9k/pair versus the $7k/pair for the MB-450.
At least in the current editions of those amps, there seem to be significant differences between the two brands not only in the output tube compliment, but also in the driver arrangements, as well as the output transformer designs. In addition, the VTL has a lower amount of feedback applied, and a correspondingly higher output impedance. While they might both be inspired by David Manley's original VTL designs and look quite similar, I wouldn't expect them to necessarily sound the same.
Zaikesman, agreed that they are likely diverging in design as time goes on. That said, I also find they have a familiar (family?) sound.

Have you listened to the Ref250 and the MB-450? I'd be interested in what you thought of the two amps as I was not able to listen to both in my system at the same time.