Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: joesatch on January 14, 2022, 01:35:12 pm

Title: Resistor type question
Post by: joesatch on January 14, 2022, 01:35:12 pm
I know this has been asked many times but i'm still not confident. I am about to build a 1987 clone and i have a stockpile of 1 Watt Metal Film Resistors (1% Blue ones). Almost every build i have come across uses Carbon Film resistors (brown)  and i have yet to  see a board populated with Metal Film (the blue ones). I am not set on vintage reproduction i just want to build a good amp with low noise. Thoughts?
Title: Re: Resistor type question
Post by: EL34 on January 14, 2022, 01:47:12 pm
1000's of amps use 1/2 watt metal film resistors

Carbon film are tan, not brown
Carbon comp are brown
Title: Re: Resistor type question
Post by: sluckey on January 14, 2022, 02:46:25 pm
I prefer metal. If I had a stockpile of 1 watters, I would not hesitate to use them.

Here are a couple of examples of my boards loaded with metal. The little blues are 1/2W metal film from Hoffman. The big blues are 3W metal oxide from Hoffman. The big grays are 2W metal oxide from AES.

http://sluckeyamps.com/phoenix/p11_big.jpg
http://sluckeyamps.com/supro/supro_02_big.jpg
Title: Re: Resistor type question
Post by: st on January 14, 2022, 03:38:32 pm
You want low (resistor) noise, go with the metal films you have. Read this: https://www.aikenamps.com/index.php/resistor-types-does-it-matter
Title: Re: Resistor type question
Post by: mresistor on January 16, 2022, 12:59:39 pm
Joe  in addition to the above comments,  I've been using metal film resistors for years..  and have even started to use the 1/2w variety but have to use high mag reader glasses to see them..    they are quite small and that may be why many people like myself use the 1w variety, much easier to read the bands (see).  Also if you are replacing plate resistors in vintage amps the 1w will be appx the same size as the 1/2w carbon composition which to me looks better,  of course some like to replace them with carbon comps to maintain originality. I don't worry much about it myself.