I need something to use at practice for vocals. We're using a solid state bass amp right now which appears to have too much gain for use with a mic. So, before I hunt down and purchase something like a PA head, I got to thinking about building something. I've built little bookshelf ipod amps using assembled tripath class D boards off of eBay, and they work great. Im wondering if anyone has experience with maybe doing something similar with a higher powered class D board (like 100 or 200W)? Or...

Hi folks!

I have a Laney LC15 that I have decided to give new life. From before a tech has added ceramic sockets for the tubes (the previous ones were plastic), and a speaker out (the cheap combo cab was totally useless, all mdf, even the baffle, and with a horrible 10 HH Invader).

But the amp itself plays nice, and I will either put it into a head cab or build a new combo cab for it (probably with 2x12 or 2x10 Weber blue alnicos). So now I wonder: What mods would you people recomend for this...

i got this thing in a lot buy years ago, and have no idea what to do with it. it seems like some really nice iron, but right now it's just a big ass paper weight. any ideas? seems like the output might be a bit low, but maybe with some sort of doubler circuit?

I have a friend who lives in Iceland, and we've talked about having me restore, build, and/or modify some pieces of gear for him. They use 220v/50Hz I think, but don't take my word for it. What exactly do I need in order to perform this work for him, if anything? Would it make a difference? I will be designing by ear, so if there could be an audible difference, then I don't want to chance it, would rather play it safe. The highest demand thing would probably be a 50w Marshall tube amp, a JCM800...

For $235 shipped, I have to say this is a nice little amp.

So, basically it's two 12ax7s in the preamp and a 12au7 in the power amp. I'm assuming the 12au7 is set up in a self-split push-pull configuration. If so, that makes this amp at least somewhat similar as Doug Hammond's Firefly circuit. I suppose the main difference is that the Lil Night Train has a two-band tone stack.

It's got a Bright/Thick switch, which seems to me to be backward. In Thick mode, the tone stack is bypassed and...

Hi gang, been away for awhile. I know everyone's been wondering where I wandered off to :? Okay, maybe not.

Well, in addition to getting married and restringing my new bride's autoharp, I did this bespoke build:

Very pleased with the outcome. Clips when available.

Hello everyone,

I have recently noticed that ALL my true bypass pedals (my DIY creations and the ones I have bought) are making a POP noise when I turn them on/off. The POP is louder as I increase the Volume of my amp (5 Watts Handwired).
Does anyone would know what the problem could be?

Thanks

Don't know if its the right place to post my question, but I'm sure there are guys here that can help.
I found few l-pad stereo attenuators but all i know about them that their wattage for single channel is 15w. Now i want to build an amp attenuator for my amp and i have 2 questions:
1. How can i measure/know what the impedance of the l-pad? As far as i know if it won't match the impedance of the amp and the cab it will damage them both.
2. Can i wire in series the two channels to get a mono...

Hey guys.

Had an idea there recently while replacing an output transformer for the Epiphone Valve Junior. The owner wanted a load box with a line-out tap installed too, so no speaker would be required.

I got to thinking.. could the output transformer not have been replaced with a 5k resistor (thats the VJ's primary impedance) of appropriate wattage rating? Then add the volume tap to that?

This is just an idea, ive no formal education in the valve amp field.
Any input would be helpful!...

I'm trying to figure out how to go about switching a cathode follower stage in and out for A/B testing. I was wondering if this would work. Not sure how to keep that dead ended switch contact within a couple volts DC of the other contacts so the switch could operate safely and keeping the tube from drawing current I may give it more thought later and it will be one of these :slap: moments. I'd rather not have to go through the process of rewiring & rewiring for listening tests because by the...

Hi all.

I'm planning on a 5E3 clone build, salvaging parts from an old Elk amp. The original Elk amp had a pair of 7189 power tubes, an EZ81 rectifier tube, and a bunch of noval pre-amp tubes. For this reason, the PT has a 6.3v tap, but no 5v tap required for the regular 5Y3 rectifier that one would usually find in a 5E3 circuit. Other than the rectifier heater voltage, the PT is okay for the 5E3 circuit (320v - 0 - 320v ample heater current etc)

After an bit of digging, it seems that the...

I am in need of modding my own Peavey 5150 II ( the mod I want costs 425$ from fjamods.com)

Fja won't do it the way I want to because he says it will cause noise issues.

Let me describe what I want and you tell me what you think:

I want to be able to have a post and pre control for the crunch mode of the rhythm channel. As it is right now, the post and pre controls are shared and can't achieve a true clean or true rhythm gain setting. its always a compromise.

So, this is what I want to...

I had a tube fail and fry a screen grid resistor in my 5150 ll. I've already ordered the new sgr's 470ohm/5watt and want to replace them all. I'm pretty good with electronics, soldering etc. but I'm not sure of the location of the resistors. I'm a complete noob at schematics but I really want to do this myself so I can learn along the way. I'm aware of the potential danger present without draining the juice. I know I can do it with some assistance. I also want to add a choke as well. Anyone...

so i recently picked up 20 of these little guys up on ebay recently for cheap, but have been having a hard time finding projects for them. anybody know anything off hand, or what i should do to adapt other submini schematics?

anybody ever had a look inside one of these amps,
the old one or the reissue?

that was the amp green recorded albatross with...

cheers
ghandi

Hi all, I've been in touch with a forum member over at Vintage Amps Forum, about making various modifications to my Vox Night Train. I carried them out this morning, powered it up and although signal is being passed.. the volume has dropped considerably. I mean to the point that on full tilt, it isn't even what I would call safe bedroom volume.. it is much lower. Here is a link to the schematic..

... dated.html

The mods were as follows..

Remove C27 - decrease in high frequency
Replaced C21...

For use with a yc25 yamaha combo organ in a rock and roll band.
Any ideas appreciated. :)

I had some time this weekend to get started on a striped down 6v6 version of a silvertone 1485. Layout and wiring shots to follow, but here's the chassis mockup for now. More pics in my Flickr album:

I think it looks a little naked above the jewel and power switch, and I forgot to put the speaker impedance above the Jack so maybe I'll redo the graphics which sucks since it went on really well this time. And if anyone has some silvertone-ish style knobs, I'd love to trade for them, I haven't...

Im looking for assistance on adding an adjustable bias pot to this amp and I would also like to up the gain on the rhythm channel. Has anyone done this or know where to find more info on how to do this? Im no electrician, but i do like to mess with electronics and do my own mods if nothing more than for bragging rights...lol! Plus i get knowledge on how the circuits work thanks for any help!

Hi guys, does anyone have schematics for a reactive attenuator? Names the type which uses a set reactive load followed by a resistive load such as an L-pad..

Thanks!

Hello,

I've started building the VTR 63 from Gitarre & Bass Magazine.

Now as this is such a cheap kit I want to make almost everything out of stuff I have laying around so it will be a very cheap reverb.

Now I was wondering. What is the actual function of grill cloth on a tube reverb cabinet. Do I need to have some sort of cloth there to provide fresh/cool air to the components to prevent overheating? If so will an old curtain do the trick? Or do I have to watch out it will not catch...

Hi

I'm getting a chance to build my own Tube Amp in a 6 day course. An ampbuilder and an electronics teacher/engineer are putting these together to supervise and explain what to do with the provided kits.

Now for me the choices to build are:
Tweed Deluxe (6V6)
Blackface Deluxe Reverb
VOX AC 15 (without tremolo)

These are the 3 that appeal to me the most. Can you give me some pointers that can help me choose between the 3?