18 watt tmb kit came with PW 5e3 transformer

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fiedlergtrs
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18 watt tmb kit came with PW 5e3 transformer

Post by fiedlergtrs »

Hi there I will apoligize upfront not up to date on this . I bought a kit on amazon 18 watt british amp from KAD ,any way they sent no layout or schematic or parts list, emailed them several times for instructions or at least schematic, this was a TMB amp they sent me ceriatone 18 watt tremelo schematic after a lot of searching and trying to figure out what parts I had,I decided to try the ceriatone 18 wat tmb layout as my board matched up and I had most of the same parts. the main problem ,I think they sent a pw 5e3 pt either 345 or 270 volt after ordering several caps and resistors and a new resistance meter to check my old one , I got together using the 270 volt . after checking volts at tubes rectifier 242 pins 1 and7 325 at pin 3 . ok plug in speaker and guitar it distorts profusely and low power, triple check everything find crack in el84 get replacements and long story shortend it is louder but distortion at any volume, is the power transformer maybe the cause?
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JMPGuitars
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Re: 18 watt tmb kit came with PW 5e3 transformer

Post by JMPGuitars »

Yes, the wrong PT could cause those issues. The target B+ (pin 3 of the EZ81 rectifier) is 345DC (+/- 5V). Much lower than that, and you would have too much distortion and no clean headroom at all...and likely it would sound muddy.

Pins 1 and 7 of the EZ81 are typically between 290 to 315VAC with properly equipped 18W power transformers (and depending on your source AC).

Thanks,
Josh
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