Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ernie_jr on June 12, 2016, 09:37:58 am

Title: output tranny suggestion
Post by: ernie_jr on June 12, 2016, 09:37:58 am

Building a bass amp 2 kt-88's with b+ of about 550V. Looking to get and Edcor o/p tranny. choices are 4200 ohm 60 watt, 4200 100 watt or 5000 ohm 100 watt. Any suggestions?
Thanks,
Ernie

Title: Re: output tranny suggestion
Post by: Paul1453 on June 14, 2016, 07:28:35 pm

Maybe this Data Sheet can help you make your choice?

https://frank.pocnet.net/sheets/084/k/KT88_GEC.pdf

Seems a UL OT might be something to consider?   :dontknow:

Title: Re: output tranny suggestion
Post by: Ed_Chambley on June 16, 2016, 04:07:36 pm

4200/100 watt.  I used a large UL Transformer from Triode.  Turned out very nice.  I am now running KT120's in it and it is plenty of volume.  Consider if you are planning to use a 5 string Bass.  If so, you want something that will get those lower frequencies.


I use it for everything, but I have a strange Bass Rig.  I used 2 NEO, 12" Eminence in a ported 2 12 cab.



I use this one:
http://www.triodeelectronics.com/a4dyoutr43oh.html (http://www.triodeelectronics.com/a4dyoutr43oh.html)


Here are the specs
Transformer specs are: 4300 ohms CT primary with screen taps, 4,8 and 16 ohm secondary. 20 Hz to 20 KHz response at 60W, within 1 db, 30 Hz to 15 KHz at 120 watts. Max DC per side (suggested) 120 ma. Exact same dimensions as the original A431 Dynaco transformer: Height 4 3/4 inches (120 mm) Width 4 inches (101 mm), Depth over covers 4 1/2 inches (114 mm), mounting centers are 3 inches (75 mm) by 3 1/2 inches (88 mm).

It is $152.00 so kind of expensive, but to me it was worth it.

Title: Re: output tranny suggestion
Post by: drgonzonm on June 18, 2016, 07:58:26 am

Bass amps, IMO, need lots of iron (check), broad range of frequency (check) and appropriate speakers,  (not checked or is this going to be a head?)