what up dawg.
i woke up this morning early. too early.
lookee, the cathode resistor is hawt because it's sinking a lotta current for a 5 watter. that aint the problem.
all is well until your power tube plates.
if this guy isn't putting .75 watt into the load, which you should verify by measurement, it HAS TO BE AN OUTPUT TRANNIE ISSUE. i swear.
if the voltages are right, and they seem to be, there's nothing attached to those plates that can mess you up except those trannies.
double double check. hook up one at a time.
i woke up this morning early. too early.
lookee, the cathode resistor is hawt because it's sinking a lotta current for a 5 watter. that aint the problem.
all is well until your power tube plates.
if this guy isn't putting .75 watt into the load, which you should verify by measurement, it HAS TO BE AN OUTPUT TRANNIE ISSUE. i swear.
if the voltages are right, and they seem to be, there's nothing attached to those plates that can mess you up except those trannies.
double double check. hook up one at a time.
Hi P
I'm quite sure the problem is in the choice of what you used for your OPT.
Look here
http://www.hammondmfg.com/263.htm
This unit cannot be successfully used as an output tranny, specially Single Ended.
See:
http://www.hammondmfg.com/1627.htm
for a good OPT, or
http://www.hammondmfg.com/125SE.htm
for a low cost unit.
Yves
noisenyc said:
I'm quite sure the problem is in the choice of what you used for your OPT.
Look here
http://www.hammondmfg.com/263.htm
This unit cannot be successfully used as an output tranny, specially Single Ended.
See:
http://www.hammondmfg.com/1627.htm
for a good OPT, or
http://www.hammondmfg.com/125SE.htm
for a low cost unit.
Yves
The output trannys are 125ESEs, I have a pair of smaller, salvaged OTs (from the amp section of a tape recorder w/built-in speakers), the primary reads 2.5K on my DVM & the secondry reads 370R. If I try one of these in place of one of the 125ESE will I damage anything?
I did paint the 125s and I'm thinking I may have loosened some wires?
P - not sticking out tongue!
I did paint the 125s and I'm thinking I may have loosened some wires?
P - not sticking out tongue!
OK - the 10 cent Akai transformer worked!! Came directly out of my CD into an old pair of NAD speakers and it played at a moderate volume and sounded pretty good!
Now the speakers are 4 ohm but that's all the specs I have, being a sealed box I suspect that they are not very efficient.
That leads us back to the Hammonds, before I pull them let me check (very stupid question approaching) that i really did hook them up correctly. The B+/1626 Plate connects to the BRN/BLU primary wires, the 8 ohm speakers connect to the BLK/YEL secondry wires.
I had to ask.
Now the speakers are 4 ohm but that's all the specs I have, being a sealed box I suspect that they are not very efficient.
That leads us back to the Hammonds, before I pull them let me check (very stupid question approaching) that i really did hook them up correctly. The B+/1626 Plate connects to the BRN/BLU primary wires, the 8 ohm speakers connect to the BLK/YEL secondry wires.
I had to ask.
Attachments
Found the problem - the banana jacks were shorting the Hammond outputs! Hahaha, who'd have thunkit?
I want to sincerely thank all you guys for the incredible help you selflessly gave in helping to tech this problem out. As I said in an earlier post, boy did I learn a lot from y'all.
Sounds pretty D-good too!
I want to sincerely thank all you guys for the incredible help you selflessly gave in helping to tech this problem out. As I said in an earlier post, boy did I learn a lot from y'all.
Sounds pretty D-good too!
Your amp looks quite nice. Any chance we might get a dark shot to see the tubes a' glowing? 
I've been looking at this project for a first tube amp as well... Although I'd rather do the parallel version for a little more power. How easy/hard was it to build? Do the 125ESE's actually sound pretty good? A lot of people put down the cheap iron... How's the bass? Highs? Mids?
Thanks
I've been looking at this project for a first tube amp as well... Although I'd rather do the parallel version for a little more power. How easy/hard was it to build? Do the 125ESE's actually sound pretty good? A lot of people put down the cheap iron... How's the bass? Highs? Mids?
Thanks
I am really happy with the sound (& the 125ESEs) though at this point have only listened through a pair of cheapo speakers. I am particularly impressed with the stereo imaging, it really is tight. The mids & highs are very crisp & the transients are strong, it may be a little bass shy but it's hard to judge with the current set up. Certainly the bass that's there is tight & defined.
I think it's a great first build, as for the power I really don't think there's much in it. A subjective doubling of acoustic output requires a 10x power factor so you would have to build at least a 5 watt variant to really notice much difference. I am certainly experiencing no problems with speakers I suspect to be in the high 80's at best.
I am embarking on a pair of TL loaded Fostex's & will report back.
Best of luck.
Philip
I think it's a great first build, as for the power I really don't think there's much in it. A subjective doubling of acoustic output requires a 10x power factor so you would have to build at least a 5 watt variant to really notice much difference. I am certainly experiencing no problems with speakers I suspect to be in the high 80's at best.
I am embarking on a pair of TL loaded Fostex's & will report back.
Best of luck.
Philip
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