Has anyone tried a Rocket/AC30 with RS deluxe OT?

[VintageCharlie]

Hi guys!

I'm wondering if anyone here has some experience with a Rocket/AC30 build that has an Radiospares Deluxe type OT of some sorts (the one that is usually found in early JTM-45 Marshalls) - it has 6.6k, 8k and 9k primaries. MM also sells one with a 3.4k instead of the 9k primary, which would approximate the 4k primary typically needed for Rocket/AC30.

I started wondering if i maybe should get this one instead of a A470, due its versatility for other builds that i'd like to experiment with.
It is also a hi-fi OT, but a rather low-budget one.

Thanks and regards,

VintageCharlie

[2tone]

I tried a tweed Bassman output in my Rocket in the 90's.. Had great low end, but missed the upper end detailed sparkle/chime....

[spiralstairs]

It certainly won't sound bad, just different. I plan on trying it eventually, I think 2tone's experience will be normal.

[Clyde]

Yes, I did one awhile back, using the 6.6k tap. It has a very complex sound, more midrangey and with more grind than the MM AC30 Haddon that we compared it to. It's more "Marshally" than "Voxy", not disagreeable at all if this is what you're aiming for. Indeed it misses some of the chime, which is more traditional AC30. The downside of this transformer is that it's hard to wire the multi-tap capabilities, but it can be done. It's hard to beat the MM transformers in my book.

[VintageCharlie]

Thanks for the valuable input guys!

Guess it's better to stick with stock OT then.
I'm surprized that the RS Deluxe doesn't fork out all the jangle and chime the VOX OT types would. I thought that it being a hi-fi OT would make it a good candidate for jangly stuff too.

[Clyde]

I'm sure it's the impedance (6.6k), rather than the transformer. I still have this build but have to remove the transformer for other reasons. I may try to hook it up to the 8k or 9k tap and halve the secondary to see if the chime is somewhere in there. When we did a shootout some time back, the higher impedances on other makes of transformers gave the same results but the RS was very much the tone monster.

[VintageCharlie]

Thanks for the info, Clyde!
Yeah, i've been reading a lot of very positive responses about this particular OT - one of those happy accidents that seems to play out perfectly in some guitar amps.
That would be very interesting to know how the OT behaves in the AC30/Rocket circuit when the 8k primary is halved to 4k. If you do this test, please keep me posted!
Btw. which RS Deluxe clone did you use? Iknow MM sells one with 3.4k, 6.6k and 8k primaries and then there's quite a few versions of the typical 6.6k, 8k, 9k configuration - from Marstran, Merren, Welter (though not a very aauthentic copy probably) and probably some others that i am not aware of.

[RJ Guitars]

I spent some time talking to the Edcor engineering guys recently about the Dynaco 470 transformer, the most commonly blessed Rocket transformer. It was their thought that the Dynaco 7 layer winding was intended to bring out the clear highs and that was at least part of the formula for the high end sparkle in that transformer when it was used in a guitar amp. They also felt that the extra winding layers were critical at the time to overcome the limitations in materials (wire, insulation, and steel) quality for transformers in that day. They believe they currently surpass the performance specifications of that transformer in a 5 layer wind in part through the use of better materials. I suspect Mercury Mag could make a similar claim... but as always, a well tuned ear is the best tool on the planet for evaluating how something sounds and only your ears know what sounds good to them. YMMV

rj

[VintageCharlie]

True, RJ - all conversations about tone are a bit helpless, because "better" or "worse" are not the right words and all the more subtle categories are not far less subjective. I would love to buy all the OT's in question and compare them, but that's simply too costly for a hobby - would be something else if it would be R&D. Hence i'm trying to gather some subjective impressions as possible way pointers.