Tape Machines > Reel to Reel Tape Machines
Hagerman Bugle
xcortes:
The Hagerman Bugle is a little battery operated phono stage kit (SS) with good press. A "half kit" (a PCB with a parts list with Digikey parts numbers) costs $39.
http://www.hagtech.com/bugle.html
The interesting point for us is that the passive RIAA network can be modified to other EQs. It looks like a very good solid state option to substitute internal electronics and add IEC eq to any machine. There's even a java calculator that tells what resistor values to substitute. Of course one needs to know the desired frequency breakpoints (turnovers) for NAB or IEC which I don't:
http://www.hagtech.com/equalization.html
I'd love to hear opinions and/or help on calculating the values for tape.
Tubes n tapes:
Xavier,
The corner frequencies for NAB and IEC are mentioned in my NAB to IEC converter article on the LAOCAS website.
http://laocaudiosociety.net/tech/NABtoIEC.pdf
Maybe that is of some use for you.
xcortes:
Thanks Arian. I knew I had seen that information somewhere!
So for NAB we have a bass zero at 50 hz and a bass pole at 40hz (the minimum allowed). On the treble side pole is 3,150 hz and zero at 50 khz. So maintaining Ca and Cb (C3 and C2 on the schematic) stock at 0.22 and 0.01uF and solving for resistors Ra, Rb, Rc and Rd (R10, R14, R8 and R13 on the schematic) we get 3.62k, 14.47k, 4.73k and 0.32k.
For IEC we maintain the bass response of NAB (ala Seduction) and set a treble pole at 4,500 hz getting 3.62k, 14.47k, 3.21k and 0.32k.
Of course R17 must be changed to a value more in accordance to each tape deck heads but, building on the Seduction 100k should be a good value to start.
xcortes:
I intend this post as a summary of the above that can be used for reference for anyone trying it.
Disclosure: I have no relation with Hagerman neither have I listened to the Bugle phono stage nor have I performed the mods here proposed. Having said that I will try them soon.
The Hagerman Bugle is a little battery operated phono stage kit (SS) with good press. A "half kit" (a PCB with a parts list with Digikey parts numbers) costs $39.
http://www.hagtech.com/bugle.html
The interesting point for us is that the passive RIAA network can be modified to other Eqs. It looks like a very good solid state option to substitute internal electronics and add NAB and/or IEC equalization to any machine.
To build a NAB version build it exactly as the RIAA version and substitute resistors R10, R14, R8, R13 and R17 with the closest you can get to the following: 3.62k, 14.47k, 4.73k, 0.32k and 100K.
To build an IEC version for your TP tapes build it exactly as the RIAA version and substitute resistors R10, R14, R8, R13 and R17 with the closest you can get to the following: 3.62k, 14.47k, 3.21k, 0.32k and 100K.
Of course a version with both eq options can be built by building the NAB version and paralelling a 10k resistor to R13 with a switch in series. Switch open you get 4.73k (NAB) and switch closed you get 3.21k (IEC).
steveidosound:
Wow. the surprising thing there is that there is only about 1.5K (give or take) change in one resistor between NAB and IEC !
BTW, if your list is consistent are you not changing the value of R8 not R13 ?
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