That's what I thought too!
But all I got back was "it's a Hiwatt in name only"type replies.
I think the tone stack might be based on this:
**broken link removed**
What do you think?
I just don't have the skill or knowledge to draw it out.
I hope you can complete the schematic,
you'd be giving me a great Christmas present!
It's great stuff!
I think they were talking about the amp I posted, the Hiwatt custom 20,
when they said Hiwatt in name only.
But am I right to say this amp is based on Hiwatt?
It certainly seems that whoever designed it took a look at Hiwatt schematics
or has access to info we don't have.
I think they were talking about the amp I posted, the Hiwatt custom 20,
when they said Hiwatt in name only.
But am I right to say this amp is based on Hiwatt?
It certainly seems that whoever designed it took a look at Hiwatt schematics
or has access to info we don't have.
Like I've said all along, valve amps are crude and simple, and easy to repair - they all look somewhat alike. In this case the specific phase splitter design, with a presence control in the feedback, makes them obviously the same make.
It certainly sounds like something is going on sound-wise.
It does not sound like a typical low-priced tube amp.
They did cheap skate the speaker, and the pcb is cheap too.
I just don't get why these guys over here are having problems solving this amp.
I replaced the speaker with an Eminence ramrod, has a British made cone,
and nice Union Jack on it too!
Nigel, you're my hero!
A magnificent job and a wonderful christmas present!
I appreciate your work tremendously!
I wish I had the knowledge.
Sounds like some of the guys I showed it to don't have the knowledge either
If they can't figure it out now, with the great work you did,well I'm thinking maybe I can send you the chassis. I'll see what happens this week.
Yes, the construction of the PCB really is horrible!
The connectors, oh boy
Maybe I can get rid of them.
But have a Merry Christmas, you deserve it!
Thanks so much!
If the hum is something you never had before and now you have it and it gets louder and louder as you turn up the volume the problem is a bad electrolitic capacitor in the power supply.
If the hum is something you have always had and something you would like to get rid of then the filter capacitors in the power supply may not be large enough to filter out all the AC pulses in the DC. You want flat line DC.
I thought the problem hum was mostly 60 hz? Full wave rectifiers have 120 hertz hum as their main harmonic. Half wave produce the 60 hertz hum. Am I thinking right on this?
I thought the problem hum was mostly 60 hz? Full wave rectifiers have 120 hertz hum as their main harmonic. Half wave produce the 60 hertz hum. Am I thinking right on this?
Yes, trouble is the supply rail is so high that scoping isnt practical due to the input voltage limitations of the Y amp, although using an attenuator may help...
If it were me, I'd just change all the components in the power supply section as there arent that many...2 diodes and a couple of caps?
If the reservoir caps have dried out or are under capacity then this would have an adverse effect on the performance of the amp...easily remedied..
Yes, trouble is the supply rail is so high that scoping isnt practical due to the input voltage limitations of the Y amp, although using an attenuator may help...
Presumably you don't have a scope?, and aren't used to using one? - there are no problems whatsoever in scoping the supply in that valve amp, and presumably that's already long since been done?.
Presumably you don't have a scope?, and aren't used to using one? - there are no problems whatsoever in scoping the supply in that valve amp, and presumably that's already long since been done?.