Jolida SD/SJ 202a …. Looking for an output transformer or substitute of same dimensions.

[bamacoo]

Hi guys, I managed to blow my right output transformer on my Jolida SJ/202a int amp.
it is a 40wpc, EL34 tube amp.
Does anyone know of a correct substitute for this amp?
I called Mike Allen of Jolida, but no stock available.
My technician is finding a challenge in sourcing one of the correct size.
The dimensions are 3 3/4”t x 2 9/16”w x 2 11/16 d

 

[JonSnell Electronic]

You could take the old frame off the faulty transformer and put one of these https://uk.rs-online.com/web/p/audio-transformers/1237237?tpr=1 inside or get the transformer rewound.
Nothing special about them.
40W per channel is a very hopeful figure if it is a HiFi amplifier. A pair of EL34s in UL mode will produce about 22 Watts RMS at less than 5% THD. 40 Watts at almost 18% THD.

 

[56085]

See page 2 of the attached Mullard datasheet for the EL34.

• 40 Watt at 4.5 % distortion with the ul-taps at 20 %
• 35 Watt at 2.5 % distortion with the ul-taps at 43 %

 

[bamacoo]

You could take the old frame off the faulty transformer and put one of these https://uk.rs-online.com/web/p/audio-transformers/1237237?tpr=1 inside or get the transformer rewound.
Nothing special about them.
40W per channel is a very hopeful figure if it is a HiFi amplifier. A pair of EL34s in UL mode will produce about 22 Watts RMS at less than 5% THD. 40 Watts at almost 18% THD.

Thank you, but wouldn’t that be out of spec if the left channel remains @40watts?
how will that fit in the existing frame.
I‘ll send you a pic.

 

[bamacoo]

See page 2 of the attached Mullard datasheet for the EL34.

• 40 Watt at 4.5 % distortion with the ul-taps at 20 %
• 35 Watt at 2.5 % distortion with the ul-taps at 43 %

Thanks, but how does that answer my question?

 

[bamacoo]

You could take the old frame off the faulty transformer and put one of these https://uk.rs-online.com/web/p/audio-transformers/1237237?tpr=1 inside or get the transformer rewound.
Nothing special about them.
40W per channel is a very hopeful figure if it is a HiFi amplifier. A pair of EL34s in UL mode will produce about 22 Watts RMS at less than 5% THD. 40 Watts at almost 18% THD.

Hi guys, I managed to blow my right output transformer on my Jolida SJ/202a int amp.
it is a 40wpc, EL34 tube amp.
Does anyone know of a correct substitute for this amp?
I called Mike Allen of Jolida, but no stock available.
My technician is finding a challenge in sourcing one of the correct size.
The dimensions are 3 3/4”t x 2 9/16”w x 2 11/16 d

 

[vinylkid58]

The dimensions are 3 3/4”t x 2 9/16”w x 2 11/16 d

A 30W Hammond 1645 might fit with the end bells removed, but there's no way to know for sure unless you have one. http://www.hammondmfg.com/1608.htm

A 30W Edcor is definitely not going to fit.

jeff

 

[bamacoo]

A 30W Hammond 1645 might fit with the end bells removed, but there's no way to know for sure unless you have one. http://www.hammondmfg.com/1608.htm

A 30W Edcor is definitely not going to fit.

jeff

Thanks Jeff. What are the end bells?

 

[vinylkid58]

The two bulbous things on either side. See red arrow.

 

[bamacoo]

The two bulbous things on either side. See red arrow.

View attachment 1050250

Jeff, thanks.
The left channel is original @40watts rms. Won’t this be a mismatch?

 

[56085]

Thanks, but how does that answer my question?

It doesn't. It is only meant to correct the faulty info put forward by "JonSnell Electronic".

Since it looks like it is impossible to get an original OPT, I would replace both OPT's to ensure both channels will be identical.

 

[vinylkid58]

Or, try and get the specs from Mike at Jolida and have the original trans rewound.

jeff

 

[bamacoo]

It doesn't. It is only meant to correct the faulty info put forward by "JonSnell Electronic".

Since it looks like it is impossible to get an original OPT, I would replace both OPT's to ensure both channels will be identical.

Thanks

 

[bamacoo]

Or, try and get the specs from Mike at Jolida and have the original trans rewound.

jeff

I did, but the factory in China is closed because of the Covid protocol

 

[Bravick]

@bamacoo

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