Want to build the ultimate "small gig" amp- perhaps two, for stereo use

[imaradiostar]

What do you prefer and why?

For years I've played through a small amp based on the Dr. Z Route 66 but using EH 7591a tubes. It's pretty loud and I usually kill some extra volume with a THD Hotplate. I've used the Rt. 66 tone control as I feel it sits better in a mix than a traditional Fender or Marshall design.

I've been struggling with the need for a small, versatile, tonally neutral amp for practice and church use. In fact I'd like to have two of them, so they could be used in stereo when effects merit it.

I'm about to build some small 9 watt push pull amps with Weber Reverb PT's and some small output transformers I have laying around. I'm figuring I'll end up with something similar but I'm open to suggestions.

Any thoughts?

jamie

[imaradiostar]

I should mention- I use a lot of pedals but think they're at their best when the amp isn't dead clean. I think the amp has to have some midrange to sound good so Fender tone stacks are generally out, except for clean sounds.

jamie

[hasserl]

I love the Fender Musicmaster Bass amps. I have 2 of them, one I leave at my bands practice pad and use it regularly for practice with the band. It can be overwhelmed if the bass & drums feel like turning it up, but at normal practice volumes it does fine. I have many amps, a Super Reverb, a Bassman, a Princeton Reverb, a 5E5A Pro, a 5E3X2, a vintage Gibson GA20, and many others. But the Musicmaster Bass sounds as good as any of them. I do some simple mods, such as rewiring the Vol/Tone controls to a tweed Fender Harvard circuit, and I use a Weber Signature Alnico 12 which works great with these amps. I suggest finding one and rebuilding it rather than building from scratch. It will be perfect for what you describe.

[imaradiostar]

Had one. Blew it up (socket went bad). Rebuilt it with a different circuit and gave it to a friend. I wish I still had it!

I did keep the phase inverter transformer though.

How would you describe the tonal difference after going to the Harvard tone control?

jamie

[imaradiostar]

Just simulated that tone circuit in Spice- looks like it's a really useful high frequency adjustment. Perhaps that and a matchless/Orange style low frequency rolloff would make for a good combination.

Has anyone else thought of making a "blackface fender" pedal for when they want that scooped fendery clean tone?

jamie

[d95err]

Has anyone else thought of making a "blackface fender" pedal for when they want that scooped fendery clean tone?

jamie

Someone has:

Tonemender

[daz]

Someone has:

Tonemender

Wow, looks like the ultimate clean boost. Has anyone made this? Seems like the perfect way to boost an amp and be able to copy anything from a transparent boost to a mid peak like a tube screamer or scooped, whatever. I may have to have a go at it, as i've made a few none of which i liked as much as my trusty tube screamer set with dist off and volumw up. But at times i wish i could have that mid boost but possibly a little more or less and some low tweaking too.

[daz]

By the way, on that schematic what is "vref"? It shows some chassis grounds but many of what should be ground say vref. I guess this is a ground of the circuit thats isolated from the chassis but direct to the battery negative for some reason?

[Steve Conner]

If you were running the circuit off the usual 9V supply, Vref would be 4.5V. Very common trick in pedals.

I'm more than happy with my Corvette Hybrid, in fact I have considered building another one for stereo. I tried jamming with a drummer the other day, and it was plenty loud enough.

For those who haven't seen it, it's a 3w Selmer practice amp with an additional transistor output stage that can be switched in to increase the power to about 40w. I kept the original cabinet, but replaced the stock speaker with an Eminence Beta 8 to handle the extra power.

[daz]

If you were running the circuit off the usual 9V supply, Vref would be 4.5V. Very common trick in pedals.

Thanks. I'm going to build one. Anyone tried it?

[cminor9]

What do you prefer and why?

For years I've played through a small amp based on the Dr. Z Route 66 but using EH 7591a tubes. It's pretty loud and I usually kill some extra volume with a THD Hotplate. I've used the Rt. 66 tone control as I feel it sits better in a mix than a traditional Fender or Marshall design.

I've been struggling with the need for a small, versatile, tonally neutral amp for practice and church use. In fact I'd like to have two of them, so they could be used in stereo when effects merit it.

I'm about to build some small 9 watt push pull amps with Weber Reverb PT's and some small output transformers I have laying around. I'm figuring I'll end up with something similar but I'm open to suggestions.

Any thoughts?

jamie

If it's based on the Z but with diff tubes I'd wager a guess it is something you built? Maybe it's too obvious, but could you redesign that amp to use 6V6s?

[jamesmafyew]

Has anyone else thought of making a "blackface fender" pedal for when they want that scooped fendery clean tone?

jamie

Jamie,

For church use I actually use two Valve Juniors in stereo. One has a closed-back 2x12 cab, the other an open-back 2x10 alnico cab. It's got a HUGE sound at a very reasonable volume -- fills up the space without seeming dominating or in-your-face. I think it might be right up your alley.

My VJs are modded so that I can either use them with neutral (no tone stack or tone control) or flip a switch and it inserts a blackface tone stack before the volume control. That's the setting I use most often. Then I have a switchable cathode bypass cap on the second triode for either no bypass (neutral), 4.7n (brilliance boost) or 1uF (Marshally mid-boost). Practicing alone, I like the brilliance boost, but playing in a group, the 1uF bypass plus the blackface stack is my favorite sound in a mix. I never have to turn down or use an attenuator, but the big speakers mean the sound is never tinny or small.

I'm local-ish to you (West Philly) so you could even come check my amps out if you wanted.

matt

[pdf64]

'Seems like the perfect way to boost an amp and be able to copy anything from a transparent boost to a mid peak like a tube screamer or scooped, whatever'

I don't think that the Tonemender would get you a mid boost tone, like a TS. Even with the bass & treb on min and mid on max, it would give a fairly flat frequency response with a little low end roll off.
How about a graphic eq pedal or a Hawk booster (clean boost + 3 band active eq)? Neither of which are easy DIY though.
Pete.

[imaradiostar]

If it's based on the Z but with diff tubes I'd wager a guess it is something you built? Maybe it's too obvious, but could you redesign that amp to use 6V6s?

Absolutely. I think it would be a great fit. Dr. Z already makes this amp- the Z-28.

jamie

[imaradiostar]

Jamie,

For church use I actually use two Valve Juniors in stereo. One has a closed-back 2x12 cab, the other an open-back 2x10 alnico cab. It's got a HUGE sound at a very reasonable volume -- fills up the space without seeming dominating or in-your-face. I think it might be right up your alley.

My VJs are modded so that I can either use them with neutral (no tone stack or tone control) or flip a switch and it inserts a blackface tone stack before the volume control. That's the setting I use most often. Then I have a switchable cathode bypass cap on the second triode for either no bypass (neutral), 4.7n (brilliance boost) or 1uF (Marshally mid-boost). Practicing alone, I like the brilliance boost, but playing in a group, the 1uF bypass plus the blackface stack is my favorite sound in a mix. I never have to turn down or use an attenuator, but the big speakers mean the sound is never tinny or small.

I'm local-ish to you (West Philly) so you could even come check my amps out if you wanted.

matt

Thanks for the offer, I may take you up on that at some point. I have a small amp that's more or less a pair of blackface champs in one chassis. I used recycled transformers from amps I took apart and it sounds OK but I never fell in love with it. I like the blackface mid scoop for clean tones but not for distortion. I think I'm going to have to build myself a pedal with a single 12ax7 and a fender tone stack in it.

As for my project I'm torn between a simple treble control like the harvard control and a two knob traynor style like I've already used on my main amp. Perhaps I'll throw together some prototypes with my Weber PT's and see how they sound. The "blackface pedal" will allow me to use that good old fender EQ when needed.

I've also considered making some small fender style amps but with a 50k audio taper pot as a mid control. At 5 out of 10 on the knob it's more or less a stock Fender; at ten it makes the tone stack mostly flat. That way the amp would be useful for the Fender tone or with other preamp pedals in front of it.

jamie