Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: pbman1953 on January 08, 2024, 11:21:31 am

Title: Re-capping a Fender Studio bass
Post by: pbman1953 on January 08, 2024, 11:21:31 am

HI All,


Happy New Year!


My next venture would to re-cap a Fender Studio Bass. Here's a link to the proposed company that sells kits for the amp-






https://www.amprepairparts.com/fendercapkits.htm (https://www.amprepairparts.com/fendercapkits.htm)


Look for the Part #FCK-19

This kit is for a Super Twin which is similar but not exact. I think that I'd have to use a radial-  750uf/ 3v. Axial's are tough to find in a small voltage


I was wondering if any other parts needed a tweak, value wise. Plus, if you would stay, with the shown 1.5 k grid resistors , or change that value.




Thanks!



 

Title: Re: Re-capping a Fender Studio bass
Post by: Latole on January 08, 2024, 12:44:11 pm

No need to replace 1,5 k grid resistors . Why ?
Read 470 ohms grid resistor and replace if needed.
Check fuse to be sure it is the right one. Too many people put more powerful fuse over years .
Amp need 6 1/4 normal/ fast blow fuse.

All you need are main and bias power supply  filter caps . Forget other caps or resitors. Values are not for this amp and amp may not need them.
You can buy from many store like Tube Depot, Antique electronics

From amprepairparts ; look here; https://www.amprepairparts.com/caps.htm#ftcap

3 F&T 22uF-500V (Main Filters - Decoupling)
2 F&T 220uF-300V (Main Filters)
2 F&T 100uF-100V (Bias Filters)

Title: Re: Re-capping a Fender Studio bass
Post by: pbman1953 on January 08, 2024, 12:50:52 pm

Perfect, thank you!

Title: Re: Re-capping a Fender Studio bass
Post by: Latole on January 08, 2024, 02:08:54 pm

You know you must  put positive + side of the bias filter cap to ground.

Title: Re: Re-capping a Fender Studio bass
Post by: pbman1953 on January 08, 2024, 02:11:35 pm

yes,thanks!

Title: Re: Re-capping a Fender Studio bass
Post by: WimWalther on January 10, 2024, 12:55:09 am

Quote from: pbman1953 on January 08, 2024, 11:21:31 am

750uf/ 3v. Axial's ae tough to find in a small voltage.

But really, you can use about any cap that fits,  from 3V to.. maybe 50V?

Title: Re: Re-capping a Fender Studio bass
Post by: d95err on January 10, 2024, 02:17:02 am

Quote from: WimWalther on January 10, 2024, 12:55:09 am

Quote from: pbman1953 on January 08, 2024, 11:21:31 am

750uf/ 3v. Axial's ae tough to find in a small voltage.

In addition to this, 750uF is a very unusual value. Anything from 470 to 1000 uF should be fine.

But really, you can use about any cap that fits,  from 3V to.. maybe 50V?

Title: Re: Re-capping a Fender Studio bass
Post by: Latole on January 10, 2024, 03:33:37 am

Quote from: pbman1953 on January 08, 2024, 11:21:31 am

HI All,


  750uf/ 3v. Axial's ae tough to find in a small voltage

MouserElectronic have many in axial from 8 to 100volts
Or Digikey ?

https://www.mouser.ca/c/passive-components/capacitors/aluminum-electrolytic-capacitors/?capacitance=750%20uF

One of them;

Title: Re: Re-capping a Fender Studio bass
Post by: pbman1953 on January 10, 2024, 07:31:51 am

Thanks guys, I saw the radial at Mouser.




Thanks!