The Amp Garage

Half the "optimum" primary impedance of a P-P pair for a P-P quad. Generally speaking, you can operate with a 2X mis-match with little risk to tubes and OT. These systems are pretty robust. Mismatching speaker loads to multitaped OT secondaries also provides another "lever" to better match primary l...

Purrrr..fect! That buzzy, ugly decay at the end of notes might also have been/be crossover distortion. It is very common in these plans and is exascerbated by pushing the tubes hard as you imply. This type of distortion also has a swirly characteristic which, in the right doseage, is kind of pleasan...

Remember: ~10% of the total tube current draw is coming from the screen contribution and can be eliminated from the plate power dissipation calculation. So....you are not quite as high on the abuse scale as you might think! :lol: Still...yes..a bump up in the cathode resistor value will be heading i...

LOL! Looks like Xitan had the same idea and punched it along while I was composing.

My sense is that you are probably good to go with a test sans light bulb limiter.

Cheers,
Dave O.

Sweet build! What is the voltage drop across your power tube cathode resistor? With that, you can calculate the power tubes' B+ current draw (plates + screens) using ohms law. Compare results with typical EL-84 curves to see if you are experiencing excessive draw for the conditions you are operating...

Hmmmm....it just dawned on me that your headphone amp vision is most likely a stereo affair.

Guitar amps are typically monophonic. Shouldn't be a problem if you are doing a scratch build though.

But....definitely post up the schematic that you are leaning toward.

Dave O.

Welcome Tony! Yes. From a very broad and general perspective, you can change the OT to match the amps power output section to a guitar speaker as opposed to a headphone "speaker". Post up your schematic or link and any information that you can find regarding its transformer and I am sure that a reas...

Whew.....good thing that you were not here last week! I had 3 nights in a row below freezing in my back yard here in SD. It didn't skin-over the swimming pool with ice but it sure took its toll on the sensitive plants that I couldn't get inside/under cover. Ok...ok...nothing close to what you are ge...

Hear, hear!
All of the very best in the new year to our brothers and sisters here at the Amp Garage!
Cheers,
Dave O.

I build most of my amps "cage" style for flexibility in mating with various speaker arrays to match the venue characteristics. Angela Instruments has been the best provider of these for my purposes. Here is one (chassis only that will also need bottom plate and cage) with just a little bit more elbo...

Here is the late 70's Explorer (pots date it at 1978) I received in trade for a custom amp (JCM-800'ish) from my childhood friend in NH. Ridden hard and put away wet is an understatement for the condition that I received it in. All of the gold hardware (except the tuners!) was heavily corroded and m...

Great to see you back Brandon! I still regularly gig with the amp that you so graciously helped me with back in 2007. Forever thankful for that.

Happy holidays!

Dave O.

Yes you can!

But...you may not get the B+ voltage that you originally sought with a full wave, CT approach.

What is the un-loaded AC voltage across the secondary?

Cheers,
Dave O.

Very nice! Tight and ballsey in high gain....but clean and full at lower guitar volume settings (I assume for the La Grange intro part)!

Can you brief us on your recording equipment approach and set up?

Well done!!!
Dave O.

What schematic are you following for the DC power supply portion of the circuit? You mention hum being one of the problems. Consider using a battery temporarily to allow focused troubleshooting on the amplifiying portion of the circuit. Hang in there! As others have said, it isn't all that complicat...