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New to AK ,bought an old tube amp ,need help

klipschoid said:
If anyone can answer this id like to upgrade opts on this unit i would prob need two 5 watt but whats the impedence that is needed on the 6aq5 side of the xformer ? I havent yet looked at parameters for a 6aq5 ,thanks anyone ,i know theres a turns ratio,but i know these packard dpa,mine is dpa5 could prob use bigger opts ,yall have a good night
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Hi K, I agree with TB, in that upgrading to better OPT is not necessary, at this stage of the game. The important thing would be to get the unit operating and sounding good. In single ended amps, the power supply has the biggest impact on sound quality, in that the better it is in terms of noise and impedance and current delivery the better your sound quality can be. Also 2 stage se amps have fewer parts and a much simpler circuit. That means the effect of each component is greater to the overall sound. With fewer parts to buy, you can perhaps spend more to get better parts. Have fun.
 
Thanks,i think thos amp prob has a 300v b+ and- with of course 6v for the rect and a 12.7 tap or two 6.3 taps tied together for the 12ax7 ,not sure **but maybe the trans will actually have reserve current now since its not powering a preamp anymore not sure ** ,i wonder is it ok to leave those connections open that powered the console pre or does it need a virtual load that emulates the old pre? Say resistor or something ,im still a freshman to some things on tube amps
 
3-5 watts from this oughtta do good for me,i have some origilsl klipsch cornwalls 1980 with crites tweeters and cap kit theyre a realistic 95-98 db efficiency,and ill use my old harman kardon avr635 as a pre for now :) ,and i get this amp to work,a fuse is mandatory and a new ac cord,maybe ill put an ole toggle on off switch later,maybe aircraft style switch lol and a pilot amber light on it of course a good repaint of chassis later ,getn it operational is first
 
This amp will function totally perfectly without the original tuner/preamp. Voltages hardly go up but maybe a couple of volts without it. Nothing noticeable or to be worried about.

The power transformer is of the basic primary windings of 6.3 volt and high voltage. All the tubes heaters work from 6.3 volts including the 12AX7. Since this one doesn't use an octal rectifier which uses a 5 volt heater, there is no 5 volt winding needed.

I noticed earlier but forgot to mention that the octal socket on the front of the amp is for its original tuner/preamp which would normally have had an on/off switch for the main power. Without it, you are probably going to have to jump a couple of wires to get it to power up. No biggie and very easy. When you get it and inspect it, take some pics and we can show you which one's. You can also try to find a schematic but whichever gets you the best results. :thumbsup:

I honestly believe that you will be pleasantly surprised at the amount of power that this thing might have. I look at it and imagine it is running 6V6 tubes only because they are bigger. The 6AQ5 and 6V6 are characteristically the same.
 
That mallory can on top of my amp have two capacitors in it? Id like to leave it,i guess i could put the new caps under chassis and leave that ?
 
If anyone has a schematic,thatd be great,i guess only plac e that would have a packard bell schem would be sams huh,thanks everyone
 
Hmmm does it appear id have to jump a wire for turn on? Ill be looking at it more,just got it in the mail ,i bought a new rect a 12ax7 and two tested 6aq5 tubes that are coming soon ,thanks guys
 
I was thinking when i get the known working tubes here and put em in ill probe where power goes with an ohm meter to see if its got a normal reading on the dvom ,and to see if its really low,like a short,wonder what an average reading probing at ac power input would be
 
klipschoid said:
I was thinking when i get the known working tubes here and put em in ill probe where power goes with an ohm meter to see if its got a normal reading on the dvom ,and to see if its really low,like a short,wonder what an average reading probing at ac power input would be
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Believe it or not, it is just a couple of ohms so don't let that confuse you.

Can't see the power transformers wires but if it has two black wires going into it, these are the 120 VAC wall socket so just make sure to complete the circuit.
 
The transformer wires likely lead directly to the power outlet. You should add a fuse for continued protection.
The only caps you need to change are the 4 in the can cap, replacing the ceramic disk caps(with another type) would improve the sound,but should work fine for testing.
 
On your earlier question about replacing the can cap, yes it's an easy way to do it, putting new ones underneath and leaving the can in place. If you need to, a screw mounted terminal strip (tag strip) is handy to hang stuff off of. And make sure you disconnect the hot leads to the original cap can so it's not in the circuit.
 
Ok thanks,ya two pins on that side octal appear to connect the power,and the tranny input from wall measures 4 ohms ,i wont try to power it up till my known good tubes come in ,all i can use is a light bulb in series ,from that to a power strip to handle any shorts ,i dont know the value of the four caps in can,guess ill try to buy a schem from,is it sams who has it? Thanks for helping
 
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