Carlos and the Texas Crude Harp Amp
I got the word from Carlos Colina that there was a harp amp of some sort for sale at a shop in Manhattan. The shop is run by a harp player who also runs a jam in Hackensack. The harmonica underground information network, which is usually quite efficient, provided only limited details. Carlos thought that it might be a Victoria bassman clone. "Why don't you give him a call?" I asked.
Carlos had just bought his second Holland amp, but he wasn't thrilled with the smaller Tweed Deluxe type amp. The bigger Holland bassman was great for the larger clubs that Carlos played in regularly, but the deluxe was too clean and not powerful enough for his tastes. He still wanted a smaller, lighter powerhouse of an amp that he could take to a small club or a jam and cut through the guitars, and not make his arm 6 inches longer from lugging it around.
Carlos called back a few minutes later, very excited. It was a Kendrick Texas Crude Harp Amp. The guy wanted $450. I almost screamed into the phone that if he wasn't going to buy it, then I certainly would. The Kendrick amps cost $2,000 - $3,000. Carlos had put a hold on it, and would go down that Thursday to check it out.
The amp was dusty, but otherwise clean and came with a soft amp cover. After 10 minutes of playing through the amp, Carlos laid down the $450 cash without further negotiations and walked out with a great little harp amp.
Later that night, Carlos called me on his cell from his bathroom. He had locked himself in the bathroom with the amp so as not to disturb the rest of the household. He had the Texas Crude up to a volume of 8 out of 12 and was playing though it in the close confines of the tiled bathroom - killer tone with no feedback!
The next night Carlos went out on his deck and serenaded the neighborhood with the volume on 12. The amp was killer. It was in perfect condition. After a light bath, the tweed covering glowed. There were no scratches or dents anywhere. It looked like it had never been used. Carlos had found true love.
The next Monday, I went down to Carlos' house with my brother, Larry. Larry brought his bass and amp. It's always strange driving down to New Jersey; they speak a funny language there and have strange customs and they drive on the wrong side of the road.
Larry and Carlos went out on the deck and played for about an hour while I fiddled with the amp's controls, trying different settings.
There are four inputs, two for instrument and two for harmonica, each one with different characteristics. There is a separate volume control for harmonica inputs and instrument inputs. One input is dark and muted and the other is brighter for each type of input. The volume control gives more change at the beginning of the range than at the end. For instance, from 1 to 4 varies the volume quite a bit, while from 4 to 12 there is not much change. This may be by design, to give a finer granularity of control at higher volumes, or it may because linear taper pots were used. The Tone Control goes from a dark and muted sound, with no highs at all to a brighter sound at 8. After 8 there seems to be little change in tone.
On the bottom of the chassis, hidden between the preamp tubes is a knob that supposedly controls the waveform symmetry. This is used to limit feedback. I found it to be too subtle for my half deaf ears. It seemed to control the tone of the amp a little. Turned all the way one way, the amp sounded raspy and dirty, but turned a little the other way the amp sounded cleaner. Out on the deck, running at 9 out of 12, there was never a feedback issue. Perhaps it would pay to fiddle this knob in a closed room with odd echoes that would initiate feedback.
When it was my turn to play (and it's always tough playing after someone like Carlos!) I tried a B-flat Big River I had stuck in my pocket before we left. Carlos had an old Shure 707 that he was playing through without a volume control. I didn't have the presence of mind to bring one of my favorite mics. I was surprised at how much tone I got through the amp. It was easily the best that I have ever sounded amplified - and the loudest. I am not a loud player and I rely on the amp to get me across. Feedback and low power amps have always been my downfall. I gotta get me one of these amps. Maybe Carlos will let me take it apart to reverse engineer it.
The amp is a 40-watt powerhouse, with two 12AX7 preamp tubes and 5881 power tubes. It has one of those huge Russian 5U4 type rectifiers. Since there are only two 12AX7 tubes there is not much in the way of preamplification circuitry so the 12AX7 tubes are working hard - that's one of the reason that the amp is good for harp. There is a polarity switch, and I can't imagine what it's doing since there is a long (20 foot) grounded power cord. There is no standby switch. I don't think Carlos will let me change the ground switch to a standby switch.
Used, these amps go for around $1,200. Carlos got a tremendous bargain. From the glimpse that I got of the circuit, it's all point-to-point wiring, no more complicated than a Fender tweed deluxe. With a low component count, it may be possible for me clone the amp so that I can have one for myself. I have been repairing and restoring amps, but I am far from being an expert amp tech. My soldering skills are still crude and I have only a limited knowledge of electronics. I have only a vague memory of my brief stint as an EE major at Cooper Union.
Kendrick doesn't make an amp in this configuration anymore. They use canary wood boxes and the amps don't look half so cool. (Canary wood is a scam as far as I can tell.) They still make the Texas Crude Harp Amp with the anti-feedback circuitry in the ugly box, but they don't list it on their online catalog page, so you have to call and negotiate on the price. I have a feeling that there is a waiting list to get one.
Just to be balanced, here are some things I don't like about the amp. The tweed was laquered with that dark color laquer. I like the brighter yellow tweed and I would have used 50-50 clear and colored laquer. The soft amp cover is funky. The amp is an odd shape and the amp cover is a pain to put on, although I have no idea how you might improve on this. The big Kendrick logo is crude - it lacks style and subtlety - but that's probably just a Texas thang. There should be a standby switch and there should not be a polarity switch. The volume controls go to 12 - why? (why not?) The tubes are crowding the speaker, and the power tubes are way too close to the speaker magnet. Why is the feedback control gizmo on the tube side of the amp where it can't be adjusted without turning the amp upside-down?
Check out http://www.kendrick-amplifiers.com for more info.