There are five different types of distortion:

1. Frequency Distortion; occurs when only select frequencies are boost or cut unevenly across the audio spectrum. This variance (or lack there of) will be reflected in the specifications as the components Frequency Response.
2. Phase Distortion; when any given frequency from a complex waveform takes longer to pass through a signal chain there is a phase shift in the individual frequencies. Even though their amplitudes may be amplified equally over the entire frequency band the compsite waveform has been varied.
3. Total Harmonic Distortion (THD); the most commonly known form of distortion is directly related to the percentage of harmonics generated by the components in the signal chain. Measuring harmonic distortion is done using Fourier Analysis.
4. Intermodulation (IM) Distortion; when an amplifier or system goes in to modulation combinations of spurious frequencies are generated. The combination of these new frequencies are equivalent to the sum and/or difference of integral multiples of the individual frequencies of a complex waveform.
5. Transient Intermodulation (TIM); many solid-state amplifiers use abundant amounts of negative feedback in order to improve frequency response and reduction of harmonic distortion. During high-frequency music passages is when this distortion occurs.

For some time now gearheads have debated the merits of PTP (point to point) wiring versus PCB (printed circuit board) in amplifiers. The benefits of each as well as the shortcomings are the source of many a heated argument.

Much of this information or mis-information comes from amplifier manufacturers themselves. Many production amplifier companies will tout how consistent the PCB method is as well as the ability to produce amplifiers at a price point many can afford. Many Boutique companies will tell you PTP is the only way to the tonal Valhalla you are searching for.

It is a fact that repairs on a PTP amplifier are often easier to perform because everything is easy to access and there is little concern over damaging the circuit board. PTP also allows for inconsistencies in even in the same model amplifier.

PCB offers a lot of bang for the buck. It also allows for hefty repairs. PCB amps can often be hard to work on and if the board itself is damaged, it may be rendered worthless.

So who is right? Who is telling the truth? What are the facts? Well I've found a few articles that talk about the facts. The first article is from the Bogner Amplification website. It is actually written by Andy Marshall of THD electronics. This man certainly knows his stuff. The second article is by Randal Smith of Mesa/boogie. This man is no slouch either.

I don't favor one over the other, in fact, I own a PTP amp as well as a PCB amp. They are both very good sounding amps and very reliable. I love both equally and play both equally. My only preference in an amp is that it sounds good and it's reliable.

Scott

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Cari amici, dopo un lungo silenzio, ritorno alla carica con un'iniziativa di Terre des hommes, spero abbastanza non convenzionale da meritare la vostra attenzione: da oggi è partito il primo TDH Video Music Contest.

Protagonisti:
- l'ormai mitico Superhero di TDH in versione rock;
- la mitica les paul della Gibson come premio;
- le band italiane, emergenti, affermate, alternative... e anche composte da un solo artista ;-) con la loro musica, la loro creatività e i loro video (rigorosamente equipaggiate di SuperHero);
- un blog: www.tdhcontest.org
- e ovviamente i bambini, al centro dell'impegno di  Terre des hommes dal 1960.

Come si fa a partecipare?
1) Si realizza un video su una propria canzone o brano musicale originale
2) Nel video deve essere presente il SuperHeroTdh, scaricabile alla pagina download SuperHero
3) Si inserisce nel video, in forma scritta o orale, la frase "La musica dà voce ai bambini, amplifica la loro voce con la tua musica!"
4) Si fa l'upload del video realizzato sul proprio spazio YouTube entro il 30 maggio 2008, inserendo le tag: Video music contest, Terre des hommes Italia, Gibson, Epiphone.
5) Si segnala il link dell'upload all'indirizzo g.didonato@tdhitaly.org specificando anche nome, cognome, indirizzo e telefono.

Selezioni, votazione e premio
I video segnalati verranno embeddati nel blog www.tdhcontest.org dove i visitatori potranno votare il loro video preferito fino alla mezzanotte del 30 giugno. Il video che avrà raccolto più voti sarà proclamato vincitore e riceverà in premio una chitarra Epiphone Les Paul Studio, offerta dalla Gibson Foundation.

Anche i visitatori potranno fare la loro parte per sostenere i progetti di TDH Italia facendo una donazione on line nell'apposita sezione del sito.

Se poi volete partecipare con il passaparola, abbiamo preparato un video (http://www.youtube.com/watch?v=93QSJxjDeBM, sì proprio quello in alto) e un banner (chiedete e vi sarà dato).

La sfida è aperta... e le sorprese per chi partecipa non sono finite. State sintonizzati su www.tdhcontest.org e grazie per l'aiuto che riuscirete a dare a Terre des hommes anche in quest'occasione

Volcano HB

Volcano H90

The HB is solid mahogany, the H90 is the newer korina body. I only compared the bridge pickups, since the H90 has a Mean 90 in the neck. Both were newly strung with GHS Boomers TNT set (10–52), played through a THD BiValve and THD 2×12 cab. I had a JJ E34L, JJ KT77, an two EH 12AX7s in the BiValve. We used a Shure SM57 to mic the cab, and then it went to some recording thing and then it was done. And I played a little out of tune, but you'll just have to deal with that.

I have to purchase an upgrade to upload MP3s, so until I do that here's a stop gap: thank you Rupert Murdoch!

Barangkali diilhami oleh konser musik "Woodstock69", maka para pemusik dan penyandang dana Indonesia menggelar acara yang mirip-mirip "Woodstock69" di TIM (Taman Ismail Marzuki) tahun 1973. Konser musik itu diberi nama "Summer28" singkatan dari Suasana Malam Hari Kemerdekaan Ke 28, yang dilangsungkan pada malam hari tanggal 16 Agustus 1973.

Turut memeriahkan pagelaran musik (terutama yang berirama rock) pertama dan terbesar pada masa itu, antara lain God Bless (Ahmad Albar, dkk. dari Jakarta), AKA (Ucok Harahap, dkk dari Surabaya), Giant Step (Benny Subardja, dkk dari Bandung), Minstreals (Jelly Tobing dkk dari Medan), dan banyak lagi group-group musik yang lagi jaya-jayanya pada masa itu.

"Summer28" memang sempat kisruh, namun tidak separah "Woodstock69". Sayangnya kini tidak ada lagi impressario yang berminat menggelar konser musik besar yang sejenis itu. Barangkali khawatir, pertunjukan musiknya akan kalah seru dan kalah heboh dengan "pertunjukan tawuran antar penontonnya".

***

Itu tahun 1973, saya yang masih sekolah di kelas 1 SMP di kampung saya di Kendal, memandang kota Jakarta tampak seperti jauuuuuuuh ....... sekali. Apalagi datang ke Jakarta, nyaris seperti sebuah mimpi. Namun di tahun yang sama dan tahun-tahun sesudah itu, saya berkali-kali menyaksikan penampilan group-group musik itu di Semarang yang jaraknya hanya 30 km dari Kendal.

Di Semarang, mereka biasanya tampil di THD (Taman Hiburan Diponegoro) dan GOR Simpang Lima. Kedua tempat dan bangunan itu sekarang sudah bablasss...sak angin-anginnya, entah dimakan butho (raksasa) dari mana. Padahal THD waktu itu termasuk Taman Hiburan yang murah-meriah.

Meskipun itu adalah pengalaman masa kecil saya lebih 25 tahun yll. Namun saya masih ingat persis karena saya lakukan berkali-kali. Setiap kali ada pementasan di THD (biasanya sebulan atau dua bulan sekali), hari Sabtu sore saya minta uang kepada almarhum ibu saya Rp 500,- (lima ratus rupiah). Perinciannya : Rp 300,- untuk ongkos naik Colt angkutan Kendal - Semarang pp. Setiba di terminal Pasar Johar lalu berjalan kaki sekitar 750 meter menuju THD di Bubakan. Sisanya untuk bayar tiket masuk THD yang besarnya Rp 200,-

Saat pertunjukan musik di mulai, saya biasanya langsung menyusup ke depan panggung di dekat loud speaker, meskipun bunyinya memekakkan telinga tapi saya dapat nonton dengan bebas dan jelas. Sebab kalau saya tidak melakukan itu, saya akan kalah bersaing dan terhalang oleh penonton-penonton lain yang umumnya lebih dewasa dan lebih besar dari saya. Maklum, wong namanya panggung terbuka murah-meriah, jadi tempat duduknya terkadang jadi tempat berdiri. Apalagi kalau habis hujan, dapat dipastikan menjadi basah.

Berangkat dari Kendal jam 19:00 malam, jam 20:00 tiba di Semarang, jam 20:30 acara dimulai, jam 22:30 acara selesai dan lalu berjalan kaki kembali ke terminal Pasar Johar menunggu angkutan, jam 00:00 tengah malam tiba kembali di rumah di Kendal. Saat menunggu Colt di Pasar Johar, biasanya sambil duduk nongkrong di pagar tempat parkir di halaman sangat luas antara Pasar Johar dengan Masjid Besar dan gedung bioskop "Rahayu", bersamaan dengan bubaran pasar Ya'ik yang digelar sore hingga malam (sebelum ada bangunan permanen Pertokoan Ya'ik Permai).

Catatan ini memang saya maksudkan untuk sekedar bernostalgia. Namun ada sedikit terselip sebuah kebanggaan, karena pengalaman semacam ini umumnya tidak dialami oleh anak-anak kecil sebaya saya pada jaman itu. Buktinya? Kalau sehabis nonton pertunjukan musik lalu keesokan harinya saya berceritera kepada teman-teman main saya, ternyata tidak nyambung. Kedengaran seperti sebuah "dongeng yang aneh". Kalau begitu, ya cukup untuk saya nikmati sendiri saja.

New Orleans, 4 Januari 2001.
Yusuf Iskandar

As you might expect, the sounds you can get from the BiValve range from garage nasty to AC/DC rockin' to deep clean. It all depends on the settings you choose and, of course, the tubes you put in. $1395 retail.

In the words of Ed Degenaro of THD, the Flexi makes the BiValve sound broken. That isn't to say the BiValve sounds bad, but that the Flexi sounds great. Obviously. Some people have said it sounds slightly Marshally, and I can see what some people mean by that, because it has that raw, throaty roar a Marshall has when it's doing it's thing, but it also has a pristine clean setting. In between the pristine and the roar are a wide variety of noises that will keep you happy for a long time.

You can hear sound clips at thdelectronics.com, or make your own sound clips by visiting the shop. $1795 retail.