Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Tubes and Hybrids => Topic started by: ilyaa on December 12, 2019, 01:06:25 AM

Title: Laney VC30 Output Transformer
Post by: ilyaa on December 12, 2019, 01:06:25 AM
if you were replacing a blown OT in this 30 Watt, 4xEl84 amp, which one would you get?

https://www.mojotone.com/amp-parts/Output-Transformers/Black-Brown-Vibrolux-Tremolux-Output-Transformer-4-8-OHM

or

http://www.triodeelectronics.com/22bastou.html

(not sure if they have that one - i e-mailed em)

or

https://www.mojotone.com/amp-parts/Output-Transformers/GA30RV-RVH-Output-Transformer

or

any other suggestions?

part of my issue is the stock transformer thats in the amp is very small - its snuggled between the second preamp 12ax7 and the PI - would like to find something small so i dont have to destroy the chassis putting the new one in.....

thank you!
Title: Re: Laney VC30 Output Transformer
Post by: phatt on December 12, 2019, 09:01:56 AM
The links are mostly for 6V6, you need a Tx for EL84.
IIRC a quad of EL84 needs a primary winding plate to plate of 4k.  Pri Z is usually just written as (4k pp) on data sheets.
Others here might know places in your location to find a Tx that will work well for that amp.
Phil.
Title: Re: Laney VC30 Output Transformer
Post by: ilyaa on December 12, 2019, 08:15:51 PM
doesnt the vibrolux/tremolux have about a 4k primary?

https://www.mojotone.com/amp-parts/Output-Transformers/Black-Brown-Vibrolux-Tremolux-Output-Transformer-4-8-OHM
Title: Re: Laney VC30 Output Transformer
Post by: ilyaa on December 12, 2019, 08:22:10 PM
oohh how about this:

https://www.mouser.com/ProductDetail/Hammond-Manufacturing/1750JA?qs=BjBf%252baFr6sPXqtmENzxjhg%3D%3D&utm_source=eciaauthorized&utm_medium=aggregator&utm_campaign=1750JA&utm_term=1750JA&utm_content=Hammond

or

https://www.mouser.com/ProductDetail/Hammond-Manufacturing/1760J?qs=itkJorDwoMKV5AXUaMbSog%3D%3D&utm_source=eciaauthorized&utm_medium=aggregator&utm_campaign=1760J&utm_term=1760J&utm_content=Hammond

those seem good, right??
Title: Re: Laney VC30 Output Transformer
Post by: phatt on December 13, 2019, 12:03:26 AM
1760J looks like it would be close.

Generally a pair of 6V6 use ~6k pp
while a pair of EL84 would be ~8k pp

The reality is,
there are many OT parameters that effect the final outcome.
Phil