Classic 30 replacement transformer (Hammond)

[jrfrond]

To answer your question, the Hammond 1645A will work fine. I just used one in an Ashdown Peacemaker for which the original was on "someday" backorder from the UK. This series is the "Easy-Wire" secondary version with simple 4/8/16Ω taps, as opposed to their standard series which uses a convoluted connection system. The primary impedance of 5K is just fine for 4- EL84's.

There is no such things as a "tube type" for a transformer. What Hammond gives is suggestions. It all depends on the primary impedance you need and the current handling.

[daz]

Heyboer will make you one. They wound an OT for my C30 pretty cheaply. But i put the stock OT back in because it sounded better !

[Jared Purdy]

OT replacement

I wish I had seen this post before I posted my inquiry, more or less the same one. Sorry for the redundancy.

I just asked a technician the exact same question yesterday. There is a repair shop in Toronto that services the entire amp/guitar community in the area (they are very busy - Superfuzzaudio.com) He (Tim) out right recommended the Mercury Magnetics OT, but reiterated the same thing, expensive. He said parts and labour would be about $200cdn.

I'm interested in hearing if anyone else has done it, not necessarily becasue they had to, but out of that eternal quest of finding that tweaking that "sound". The youtube demo on the epiphone valve junior clearly shows that there is a remarkable difference.

[MWJB]

"The youtube demo on the epiphone valve junior clearly shows that there is a remarkable difference." You need to reference the ecxact Youtube clip...the only clips I can find are for the V JR mod, and not for a comparison on 2 valve jrs, one with a stock OT and the other with a MM OT...?

Maybe you, or someone else, can point me to the clip to which you refer.

[wizard333]

I'm interested in hearing if anyone else has done it,

See above.

Like I said, I really could only hear a difference stock vs the MM OT at very high volumes, well into clean channel breakup. And I was comparing a bone stock C30 with the MM OT one side by side, not at different times.

If you're looking for bang for the buck, look elsewhere. There are cheaper easier things you can do to a C30 that will make a FAR larger change in the tone than a different OT.

[Jared Purdy]

epiphone valve junior ot mod @ youtube

"The youtube demo on the epiphone valve junior clearly shows that there is a remarkable difference." You need to reference the ecxact Youtube clip...the only clips I can find are for the V JR mod, and not for a comparison on 2 valve jrs, one with a stock OT and the other with a MM OT...?

Maybe you, or someone else, can point me to the clip to which you refer.

Heres the link. This is part two, the first part just shows the initial installation

YouTube - Mercury Magnetics Epiphone Valve JR Amp Mod Build Part 2

Regards

[Jared Purdy]

Interesting, Weber will not offer replacements or refunds on Heyboer OTs. I wonder if there is any connection between your experience (which clearly suggests that it didn't work!) and the cost of their product?

[Enzo]

I would also point out that a C30 is not a Valve Junior. it is rather loose to want a C30 transformer based on a VJ swap.

[Jared Purdy]

I realize that there are likely quite a few differences between the VJ and the C30 (wattage, speaker type and size, capacitor values, cabinet type, circuit board, etc.,). I guess what it got me wondering is if the same changes would result with the C30 and a MM OT??

I also particiapte on the Peavey Forum "Whammy Bar and Grill". One of the regulars changed out the OT in his Valve King and reported the same stellar results. Its just got me wondering....

[MWJB]

Yes, I saw this. It is not a comparison between a V JR with a stock OT and a V Jr with a MM OT - the modded V JR has been extensively reworked, with an additional power tube & new transformers all round. This is nothing like the difference that you would see when just changing an OT.

[MWJB]

"I guess what it got me wondering is if the same changes would result with the C30 and a MM OT??" NO, NO, NO! The changes would NOT be the same because the changes you see on the V Jr do not result solely from a OT swap.

Hyboer trannies are excellent, the benchmark for repro Fender trannies, whether Weber do refunds on them or not. Weber would rather you bought their chinese transformers.

[Jared Purdy]

what cheaper things did you have in mind

See above.

Like I said, I really could only hear a difference stock vs the MM OT at very high volumes, well into clean channel breakup. And I was comparing a bone stock C30 with the MM OT one side by side, not at different times.

If you're looking for bang for the buck, look elsewhere. There are cheaper easier things you can do to a C30 that will make a FAR larger change in the tone than a different OT.

Great post by the way. Yes, it is a cost that too makes me wonder, though I will likely do it. I'm beginning to lean towards the idea that my C30 will be my long term pet project (not a la Steve Aloha), but maybe a few less invasive changes, and an OT is likely on the cards. So what other cheaper changes are you referring to?

[MWJB]

"So what other cheaper changes are you referring to? " Tube & speaker selection, virtually any resistor in the amp can be halved or doubled...that's A LOT of mods, so I don't recommend any specific changes until you can decide what it is that your amp lacks tonally, or unless you stumble accross a mod that seems to do something you might like...don't just change bits for changes sake, make sure the changes have a purpose and go through with them if that purpose suits what you are hearing. Do changes one at a time, live with them for a while...unless you hear straight away that you don't like them.

So first stop is to keep playing through your amp until you find a trait that you don't like.

[Steve Conner]

The other important thing to understand is that the VJr is a single-ended amp, whereas the Classic 30 is push-pull. By their very nature, single-ended amps are more sensitive to OT changes than PP ones.

Geek disclosure: In a SE amp, the power tube only provides half of the waveform to the loudspeaker. Stored inductive energy in the OT core delivers the other half. A larger OT can store more energy and deliver it with less losses, and the result is more headroom and more bass. It doesn't need to be some expensive boutique brand to get this improvement, just bigger.

In a PP amp, each tube (or pair thereof) provides half of the waveform, and the OT is just there to pass it along to the speaker. It has no need to store any energy, which makes it a less critical part. As others have said, you probably won't notice a difference unless you're cranking the thing flat out. An undersized OT will constrict the bass somewhat at high volumes, and Fender probably used that to their advantage to keep the speakers in their tweed Bassman alive.

Whereas with a SE amp, swapping the OT makes a real, big, measurable difference at all volumes.

[MWJB]

All good points Steve - but the point that I have been trying to make with the MM V Jr mod, is that the video shows a considerably reworked amp with an additional power tube & ALL new transformers - differences are NOT typical of a new OT alone, in ANY amp.

Just didn't want this detail to go overlooked.

+1 for what Steve says re. PP amps - subbing an OT for another, of broadly the same type (primary Z, W rating, size) will only give a subtle change in tone. If you have been listening to amps with a preferred OT in for years, then you might notice a small deficiency...but we're talking a few % of the overall tone & dynamics.

I have listened to hundreds of Fender bassmans, most with the RI OT, some with original Triad, some with custom wound...the best sounding amps were the best sounding amps, a megabucks OT won't help you if the rest of the amp isn't up to snuff. For example, the treble slope resistor value makes more difference than different, functioning OTs.