Ampeg SVT III Non Pro - 1º Version

[Sandro80]

Hi Everyone.

I have a Ampeg SVT III Non Pro Amplifier.
I need your help in secondary voltages power transformer, because the original (94-615-20) Blowing.
A one my friend specialised in rewing transformers, had a bad job because is a complex power transformer..for rewinding because primary windings and secondary.

I need one person have any information about the output voltages in two secondary voltages wires output.
I have a shematic, and In last week I send the Ampeg (Line6), but he not ahev any information about the secondary voltages in power transformer wires output.

This original power transformer have Two secondary outputs. The primary is a common voltages...110V, 115V, 220V and 240V.

RED Wire- ?
Yellow- 0V
RED Wire- ?

Orange Wire - ?
Green - 0V
Orange- ?

The "new" Ampeg owners advide my this voltages is probably the same voltages in Power transformer of Ampeg SVTIII PRO, but is a mistake, because He not have any information of this correct output voltages.

In this week I put new pohotos about original the traformer...rewind bad service...


Have nice week and I hope any help.
Best Regards to everyone.
Sandro

I need your help for try new life for my Ampeg SVTIII Non Pro.
I apreciate your help and any consideration.

[Enzo]

SVT3 secondaries are red/green/red and orange/yellow/orange. Don't mix your center taps.

Transformer 94-615-20

The red wires rectify and filter to 61vDC, so the red wires roughly 45-0-45vAC

The yellow wires rectify and filter to 22vDC for the 15v supplies, so I expect AC voltage roughly 16-0-16vAC.


The SVTPRO3 won't work, the main red wire winding makes 65v so it would be similar, but the Pro has the tube preamp and has a 300v supply for that, the 15v for the op amps comes from drops off the 65v. So it has the extra high voltage winding and lacks the low voltage winding.

[Sandro80]

Hi Mr. Enzo.

You are a famous electronic tecnician.
I see your posts in pasts years and you have great knowledge. ))

Tomorrow I post new pictures with the transformer.

About not mix the center tapes?

The correct is ?
(First Secondary(Red 45V , Green 0V RED 45V ;
Second secundary: Orange: 16V , Yellow 0V , Orange 16V ?

Thanks for all and if you need any shematic I post in next days some rarely...shematics.

Have a nice week and very good christmas.

Sandro

[hodgy]

I'm sorry Sandro, how is it bad service when we supply you with all of the information that we have available? Unfortunately for all of us, Yamaha Guitar Group was only supplied with documentation that was supplied by Loud Audio, which was supplied by St. Louis Music. Which on an amp this old I would say we're lucky to have what documentation that we DO have. Perhaps your "Bad Service" comment needs to be directed at St. Louis Music who designed the amp but failed to archive a spec sheet for a transformer that hasn't been used in a product since 1994?

[Justin Thomas]

Given the possibility of a language barrier, I don't think the "bad service" was directed to anyone here. It was in the first post, after all. And I have a feeling perhaps Sandro is trying to undo some bad work from a previous tech. Just my gut...

Justin

[drewl]

Yeah, a little translation mix up.

So, I'm sure a power trans from a similar type amp like an old Peavey would probably work.
it's the physical size configuration that is a problem trying to get one to fit.

Perhaps a toroidal one?

[Helmholtz]

I am somewhat surprised. If someone "specializes in rewinding transformers" I'd expect him to count turns numbers of the original. And if he used the same turns numbers, voltages must be the same.
What voltages do you get?

[g1]

I'm sorry Sandro, how is it bad service when we supply you with all of the information that we have available?

I think the 'bad service' comments were about the TX rewind he had done.

(P.S. Nice to see you drop by Hodgy! Sounds like you are with Yamaha now. )

[Sandro80]

Hi.

Ups...
Sorry for this mistake.
I not never refer bad service in Ampeg feedbacks to my email in last week. I send one email to Ampeg (Line6), and I have better references with your possible helps.I undestand if this Amplifier is old and it´s impossible find all documentation...past 30 Years.
I put this original transformer in one local rewinder store...and it go a bad service in secodary rewinds because He aceppt other services, before has been conclued my Ampeg power transformer in good condition.

The primary works okay , but I try go one more time for this local store rewind one more time all secondary rewinds...in good condition.

Sorry for my last poor explanation , about this store.
Ampeg, has been send to me nice explanation possible with my questionm and I have gratefull for all help and yours good coments, i this post.
I put new photos of this rewind incompleted...service, for you "apreciate".

Thanks
Sandro

[Sandro80]

Hi Mr. Hodgy.
Sorry for this mistake. I not speak about Ampeg and your email , you send to me in last week.
I´m gratefull for your help.
I speak for local store rewind transformers...
See my last post.
I try put the transformer photos, but not able because exced the limit of this pictures.

I try tomorrow post this photos.

Thanks for all.

Sandro

[Sandro80]

g1 I have a one Yamaha B100 head first model from 1978.

[Justin Thomas]

You may be able to use a lower resolution on your camera so your pictures can load without exceeding the limit.

Maybe that'll help...

Justin

[hodgy]

Hi Mr. Hodgy.
Sorry for this mistake. I not speak about Ampeg and your email , you send to me in last week.
I´m gratefull for your help.
I speak for local store rewind transformers...
See my last post.
I try put the transformer photos, but not able because exced the limit of this pictures.

I try tomorrow post this photos.

Thanks for all.

Sandro

I apologize for jumping on you Mr. Sandro. I'm glad that you see that we try to help out the best we can with what information we have available.
I wish you the best of luck on your transformer.
If that doesn't work, maybe you'd be interested in a new (***Shameless Plug*****) 50th Anniversary SVT perhaps? LOL.

G1: Yes, I stuck with Ampeg when Yamaha bought the brand. I lurk in here occasionally, but since I stopped doing repairs I'm not here as much.

[Mick Bailey]

Hi Hodgy, nice to see you back here - it's been a while and I'm always interested in your posts.